Agricultural and Biological Sciences › Food Science

Fermentation and Sensory Analysis

Works Count: 63563

Wikipedia

Description

This cluster of papers explores the intricate microbial interactions, genetic diversity, and metabolic processes involved in wine production, with a focus on yeast strains, aroma compounds, polyphenols, and fermentation dynamics. It delves into the impact of grape metabolism, microbial terroir, and biogenic amines on the flavor profile of wines.

Keywords

Wine Yeasts; Microbial Modulation; Aroma Compounds; Polyphenols; Fermentation; Saccharomyces cerevisiae; Grape Metabolism; Flavor Profile; Biogenic Amines; Microbial Terroir

The primary structure of the Saccharomyces cerevisiae gene for alcohol dehydrogenase.

1982-03-01

Jeffrey L. Bennetzen , B. D. Hall

The DNA sequence of the gene for the fermentative yeast alcohol dehydrogenase has been determined.The structural gene contains no introns.The amino acid sequence of the protein as determined from the … The DNA sequence of the gene for the fermentative yeast alcohol dehydrogenase has been determined.The structural gene contains no introns.The amino acid sequence of the protein as determined from the nucleotide sequence disagrees with the published alcohol dehydrogenase isozyme l (ADN-I) sequence for 5 of the 347 amino acid residues.At least one, and perhaps as many as four, of these differences is probably due to ADH-I protein heterogeneity in different yeast strains and not to sequencing errors.S1 nuclease was used to map the 5' and 3' ends of the ADH-I mRNA.There are two discrete, mature 5' ends of the mRNA, mapping 27 and 37 nucleotides upstream of the translation initiating ATG.These two equally prevaIent termini are 101 and 91 nucleotides, respectively, downstream from a TATAAA sequence.Analysis of the 3' end of ADH-I mRNA disclosed two minor ends upstream of the major poly(A) addition site.These three ends map 24,6?, and 83 nucleotides, respectively, downstream from the translation-terminating TAA triplet.The sequence AA-TAAG is found 28 to 34 nucleotides upstream of each ADH-I mRNA poly(A) addition site.Sequence comparisons of these three 3' ends with those for four other yeast mRNAs yielded a 13-nucleotide consensus sequence to which TAAATAA; is central.All of the known yeast poly(A) addition sites map at or near the A residue of a E A site 25 to 40 nucleotides downstream from this consensus octamer.Among the enzymes in yeast which are involved in glycolysis and alcoholic fermentation, alcohol dehydrogenase is the most extensively characterized by genetic means (1-5).Yeast mutants lacking functional alcohol dehydrogenase are readily selected on plates containing allyl alcohol which is converted by alcohol dehydrogenase to the toxic compound acrolein (3, 4).Combined enzymological and genetic studies have established that yeast cells possess three isozymes of alcohol dehydrogenase coded by different structural genes (3, 4).The two cytoplasmic enzymes ADH-I' and ADW-I1 are closely

Yeast and its Importance to Wine Aroma - A Review

2019-06-01

Marius G. Lambrechts , Isak S. Pretorius

Wine aroma; wine flavour; fermentation bouquet; wine yeastThe most mysterious aspect of wine is the endless variety of flavours that stem from a complex, completely non-lin ear system of interactions … Wine aroma; wine flavour; fermentation bouquet; wine yeastThe most mysterious aspect of wine is the endless variety of flavours that stem from a complex, completely non-lin ear system of interactions among many hundreds of compounds.In its widest sense, wine flavour refers to the over all impression of both aroma and taste components.Aroma is usually associated with odorous, volatile compounds; the bouquet of wine refers to the more complex flavour compounds which evolve as a result of fermentation, ele vage and ageing.With the exception of terpenes in the aromatic grape varieties and alkoxypyrazines in the herba ceous cultivars, perceived flavour is the result of absolute amounts and specific ratios of many of these interactive compounds, rather than being attributable to a single "impact" compound.Without underestimating the complex ity of these interactive effects or negating the definitive role played by the accumulated secondary grape metabo lites in the varietal character of wine, this review will focus mainly on the contribution of yeast fermentation to the sensorial quality of the final product.Yeast and fermentation conditions are claimed to be the most important fac tors influencing the flavours in wine.Both spontaneous and inoculated wine fermentations are affected by the diversity of yeasts associated with the vineyard and winery.During the primary alcoholic fermentation of sugar, the wine yeast, Saccharomyces cerevisiae, together with other indigenous non-Saccharomyces species, produce ethanol, carbon dioxide and a number of by-products.Of these yeast-derived metabolites, the alcohols, acetates and C4-C8 1tfatty acid ethyl esters are found in the highest concentration in wine.While the volatile metabolites contribute to the fermentation bouquet ubiquitous to all young wines, the production levels of these by-products are variable and yeast strain specific.Therefore, this article also highlights the importance of untapping the hidden wealth of indige nous yeast species present on grapes, and the selection and genetic development of yeast starter culture strains with improved flavour profiles.In the future, some winemakers may prefer to use mixtures of indigenous yeast species and tailored S. cerevisiae strains as starter cultures to reflect the biodiversity and stylistic distinctiveness of a given region.This will help winemakers to fullfil the consumer's demand for individual wines with intact local character and to ensure the survival of wine's most enthralling aspect -its endless variety.E<lmm> l +-/ ' ,.., A,a.-.. y_ H;gb� """"• , ...

View PDF Chat

A Review of the Effect of Winemaking Techniques on Phenolic Extraction in Red Wines

2005-09-01

Karna L. Sacchi , Linda F. Bisson , Douglas O. Adams

Winemaking variables and techniques are known to affect the phenolic composition of red wines. This review surveys the current literature on the impact of processing and fermentation parameters on the … Winemaking variables and techniques are known to affect the phenolic composition of red wines. This review surveys the current literature on the impact of processing and fermentation parameters on the phenolic profile of the finished wines. Six winemaking variables and techniques have been reported to increase phenolic concentration: fermentation temperature, thermovinification, must freezing, saignée, pectolytic enzyme treatments, and extended maceration. In contrast, sulfur dioxide levels and cold-soak treatments have frequently been shown to have no or little lasting effect or to lead to a decrease in phenolic levels. Finally, carbonic maceration, yeast selection, and skin and juice mixing practices have produced variable results depending on the grape varieties studied.

View PDF Chat

The microbial ecology of wine grape berries

2011-12-07

André Barata , Manuel Malfeito‐Ferreira , V. Loureiro

Implications of nitrogen nutrition for grapes, fermentation and wine

2005-10-01

Sally‐Jean Bell , Paul A. Henschke

This review discusses the impacts of nitrogen addition in the vineyard and winery, and establishes the effects that nitrogen has on grape berry and wine composition and the sensory attributes … This review discusses the impacts of nitrogen addition in the vineyard and winery, and establishes the effects that nitrogen has on grape berry and wine composition and the sensory attributes of wine. Nitrogen is the most abundant soil-derived macronutrient in a grapevine, and plays a major role in many of the biological functions and processes of both grapevine and fermentative microorganisms. Manipulation of grapevine nitrogen nutrition has the potential to influence quality components in the grape and, ultimately, the wine. In addition, fermentation kinetics and formation of flavour-active metabolites are also affected by the nitrogen status of the must, which can be further manipulated by addition of nitrogen in the winery. The only consistent effect of nitrogen application in the vineyard on grape berry quality components is an increase in the concentration of the major nitrogenous compounds, such as total nitrogen, total amino acids, arginine, proline and ammonium, and consequently yeast-assimilable nitrogen (YAN). Both the form and amount of YAN have significant implications for wine quality. Low must YAN leads to low yeast populations and poor fermentation vigour, increased risk of sluggish/stuck/slow fermentations, increased production of undesirable thiols (e.g. hydrogen sulfide) and higher alcohols, and low production of esters and long chain volatile fatty acids. High must YAN leads to increased biomass and higher maximum heat output due to greater fermentation vigour, and increased formation of ethyl acetate, acetic acid and volatile acidity. Increased concentrations of haze-causing proteins, urea and ethyl carbamate and biogenic amines are also associated with high YAN musts. The risk of microbial instability, potential taint from Botrytis-infected fruit and possibly atypical ageing character is also increased. Intermediate must YAN favours the best balance between desirable and undesirable chemical and sensory wine attributes. 'Macro tuning', of berry nitrogen status can be achieved in the vineyard, given genetic constraints, but the final 'micro tuning' can be more readily achieved in the winery by the use of nitrogen supplements, such as diammonium phosphate (DAP) and the choice of fermentation conditions. This point highlights the need to monitor nitrogen not only in the vineyard but also in the must immediately before fermentation, so that appropriate additions can be made when required. Overall, optimisation of vineyard and fermentation nitrogen can contribute to quality factors in wine and hence affect its value. However, a better understanding of the effect of nitrogen on grape secondary metabolites and different types of nitrogen sources on yeast flavour metabolism and wine sensory properties is still required.

Yeast and bacterial modulation of wine aroma and flavour

2005-07-01

Jan H. Swiegers , Eveline Bartowsky , Paul A. Henschke +1 more

Wine is a highly complex mixture of compounds which largely define its appearance, aroma, flavour and mouth-feel properties. The compounds responsible for those attributes have been derived in turn from … Wine is a highly complex mixture of compounds which largely define its appearance, aroma, flavour and mouth-feel properties. The compounds responsible for those attributes have been derived in turn from three major sources, viz. grapes, microbes and, when used, wood (most commonly, oak). The grape-derived compounds provide varietal distinction in addition to giving wine its basic structure. Thus, the floral monoterpenes largely define Muscat-related wines and the fruity volatile thiols define Sauvignon-related wines; the grape acids and tannins, together with alcohol, contribute the palate and mouth-feel properties. Yeast fermentation of sugars not only produces ethanol and carbon dioxide but a range of minor but sensorially important volatile metabolites which gives wine its vinous character. These volatile metabolites, which comprise esters, higher alcohols, carbonyls, volatile fatty acids and sulfur compounds, are derived from sugar and amino acid metabolism. The malolactic fermentation, when needed, not only provides deacidification, but can enhance the flavour profile. The aroma and flavour profile of wine is the result of an almost infinite number of variations in production, whether in the vineyard or the winery. In addition to the obvious, such as the grapes selected, the winemaker employs a variety of techniques and tools to produce wines with specific flavour profiles. One of these tools is the choice of microorganism to conduct fermentation. During alcoholic fermentation, the wine yeast Saccharomyces cerevisiae brings forth the major changes between grape must and wine: modifying aroma, flavour, mouth-feel, colour and chemical complexity. The wine bacterium Oenococcus oeni adds its contribution to wines that undergo malolactic fermentation. Thus flavour-active yeasts and bacterial strains can produce desirable sensory results by helping to extract compounds from the solids in grape must, by modifying grape-derived molecules and by producing flavour-active metabolites. This article reviews some of the most important flavour compounds found in wine, and their microbiological origin.

View PDF Chat

A rapid gas chromatographic method for the determination of poly-?-hydroxybutyric acid in microbial biomass

1978-01-01

G. Braunegg , B. Sonnleitner , R. M. Lafferty

Analysis of Proanthocyanidin Cleavage Products Following Acid-Catalysis in the Presence of Excess Phloroglucinol

2001-03-22

James A. Kennedy , Graham P. Jones

The analysis of proanthocyanidin cleavage products after acid-catalysis in the presence of excess phloroglucinol was investigated. In the developed analytical method, a solution of 0.1 N HCl in methanol, containing … The analysis of proanthocyanidin cleavage products after acid-catalysis in the presence of excess phloroglucinol was investigated. In the developed analytical method, a solution of 0.1 N HCl in methanol, containing 50 g/L phloroglucinol and 10 g/L ascorbic acid was prepared. The proanthocyanidin of interest was reacted in this solution (5 g/L) at 50 °C for 20 min, and afterward combined with 5 volumes of 40 mM aqueous sodium acetate before analysis by reversed-phase HPLC using an aqueous acetic acid and methanol gradient. This procedure was used to investigate the composition of proanthocyanidins isolated from the seed and skin tissue of Vitis vinifera L. berries. The results compared favorably to results obtained when benzyl mercaptan was used as the trapping nucleophile, indicating that phloroglucinol is an effective reagent for this analysis. Keywords: Proanthocyanidin; tannin; flavan-3-ol; molar absorptivity; Vitis vinifera; grape; phloroglucinol; benzyl mercaptan; thiolysis; yield

Yeast interactions and wine flavour

2003-07-07

George W. J. Fleet

Quantitative determination of the odorants of young red wines from different grape varieties

2000-01-01

Vicente Ferreira , Ricardo L�pez , Juan Cacho

Fifty-two young monovarietal red wines made with Grenache (17 samples), Tempranillo (11 samples), Cabernet Sauvignon (12 samples) and Merlot (12 samples) grapes have been analysed by HRGC–MS to obtain quantitative … Fifty-two young monovarietal red wines made with Grenache (17 samples), Tempranillo (11 samples), Cabernet Sauvignon (12 samples) and Merlot (12 samples) grapes have been analysed by HRGC–MS to obtain quantitative data on 47 odorants previously identified as potential aroma contributors by olfactometric techniques. Thirty-three odorants were present in the wines at concentrations higher than their corresponding odour thresholds. These include ethyl octanoate, β-damascenone, ethyl hexanoate, isovaleric acid and isoamyl acetate as the most important, which together with isoamyl and β-phenylethyl alcohols, fatty acids, 2,3-butanedione and ethyl butyrate are always found at concentrations higher than their odour thresholds. In some cases the ethyl esters of isobutyric and isovaleric acids, β-ionone, methionol, isobutyric acid, ethyl cinnamate, ethyl dihydrocinnamate, γ-nonalactone, eugenol, c-3-hexanol, geraniol, guaiacol, 3-isobutyl-2-methoxypyrazine, 4-ethylguaiacol, acetoin and t-whiskylactone were at a concentration high enough to be odour-active. There were 30 compounds that were found to differ significantly between varieties. These include 3-isobutyl-2-methoxypyrazine, isoamyl acetate, isovaleric acid, ethyl isobutyrate, ethyl isovalerate, fusel alcohols, c-3-hexenol, methionol, eugenol, guaiacol and γ-nonalactone. © 2000 Society of Chemical Industry

View PDF Chat

The chemistry of beer aging – a critical review

2005-03-05

Bart Vanderhaegen , Hedwig Neven , H. Verachtert +1 more

The origin of ethylphenols in wines

1992-01-01

Pascal Chatonnet , Denis Dubourdie , Jean‐Noël Boidron +1 more

Abstract Ethylphenols are important aromatic compounds of red wines. These compounds are formed in wines by some yeast species belonging to the genus Brettanomyces/Dekkera in the presence of hydroxycinnamic acids. … Abstract Ethylphenols are important aromatic compounds of red wines. These compounds are formed in wines by some yeast species belonging to the genus Brettanomyces/Dekkera in the presence of hydroxycinnamic acids. These volatile phenols are responsible for the ‘phenolic’, ‘animal’ and ‘stable’ off‐odours found in certain red wines. The results presented show that the synthesis of the high quantities of ethylphenols found in the ‘phenolic’ red wines can occur during the ageing of wines having normally completed their alcoholic and malo‐lactic fermentations. This olfactory fault caused by Brettanomyces/Dekkera is found more frequently than the classical ‘mousy‐taint’ attributed to this yeast genus. In addition, the study of the mechanisms of biosynthesis of ethylphenols by Brettanomyces/Dekkera has shown the sequential activities of two enzymes. The first, is a cinnamate decarboxylase (CD), which assures the transformation of certain cinnamic acids into the correspondent vinylphenols; the second is a vinylphenol reductase, which catalyses the reduction of vinylphenols into ethylphenols. The CD activity of Brettanomyces/Dekkera is not inhibited by the polyphenolic compounds of red wines (procyanidins and catechins) while these compounds do inhibit the CD activity of Saccharomyces cerevisiae. On the other hand, the substrate specificities of the CD activities of Brettanomyces/Dekkera and Saccharomyces are different.

Quantitation and Sensory Studies of Character Impact Odorants of Different White Wine Varieties

1997-08-01

H. Guth

Forty-four odor-active compounds were quantified in Scheurebe and Gewürztraminer wines, respectively. Calculation of odor activity values (OAVs) of odorants showed that differences in odor profiles of both varieties were mainly … Forty-four odor-active compounds were quantified in Scheurebe and Gewürztraminer wines, respectively. Calculation of odor activity values (OAVs) of odorants showed that differences in odor profiles of both varieties were mainly caused by cis-rose oxide in Gewürztraminer and by 4-mercapto-4-methylpentan-2-one in Scheurebe. On the basis of their high OAVs, ethyl octanoate, ethyl hexanoate, 3-methylbutyl acetate, ethyl isobutyrate, (E)-β-damascenone, and 3a,4,5,7a-tetrahydro-3,6-dimethylbenzofuran-2(3H)-one (wine lactone) were further potent odorants in both varieties. The compounds were dissolved in a water/ethanol mixture in various combinations and in concentration levels equal to those in wine. The results indicated that the aromas of Gewürztraminer and Scheurebe models were in good agreement with the original wines. Keywords: Gas chromatography; stable isotope dilution assay; quantitation; white wine; Gewürztraminer; Scheurebe

Radial diffusion method for determining tannin in plant extracts

1987-03-01

Ann Hagerman

Analytical Characterization of the Aroma of Five Premium Red Wines. Insights into the Role of Odor Families and the Concept of Fruitiness of Wines

2007-05-01

Ana Escudero , Elı́as Campo , Laura Fariña +2 more

The aroma profile of five premium red wines has been studied by sensory descriptive analysis, quantitative gas chromatography-olfactometry (GC-O), and chemical quantitative analysis. The most relevant findings have been confirmed … The aroma profile of five premium red wines has been studied by sensory descriptive analysis, quantitative gas chromatography-olfactometry (GC-O), and chemical quantitative analysis. The most relevant findings have been confirmed by sensory analysis. Forty-five odorants, including the most intense, were identified. At least 37 odorants can be found at concentrations above their odor threshold. A satisfactory agreement between GC-O and quantitative data was obtained in most cases. Isobutyl-2-methoxypyrazine, (E)-whiskey lactone, and guaiacol were responsible for the veggie, woody, and toasted characters of the wines, respectively. The sweet-caramel notes are related to the presence of at least five compounds with flowery and sweet notes. The phenolic character can be similarly related to the presence of 12 volatile phenols. The berry fruit note of these wines is related to the additive effect of nine fruity esters. Ethanol exerts a strong suppression effect on fruitiness, whereas norisoprenoids and dimethyl sulfide enhance fruity notes.

Selected non-Saccharomyces wine yeasts in controlled multistarter fermentations with Saccharomyces cerevisiae

2010-12-12

Francesca Comitini , Mirko Gobbi , Paola Domizio +4 more

Extending Applicability of the Oxygen Radical Absorbance Capacity (ORAC−Fluorescein) Assay

2003-12-16

Alberto Dávalos , Carmen Gómez‐Cordovés , Begoña Bartolomé

The ORAC-fluorescein (ORAC−FL) method recently validated using automatic liquid handling systems has now been adapted to manual handling and using a conventional fluorescence microplate reader. As calculated for Trolox, the … The ORAC-fluorescein (ORAC−FL) method recently validated using automatic liquid handling systems has now been adapted to manual handling and using a conventional fluorescence microplate reader. As calculated for Trolox, the precision of the method was <3.0, expressed as percent coefficient of variation. The accuracy of the method was <2.3, expressed as percent variation of the mean. The detection and quantification limits were those corresponding to 0.5- and 1-μM Trolox standard solutions, respectively. The method has been applied to 10 pure compounds (benzoic and cinnamic acids and aldehydes, flavonoids, and butylated hydroxyanisole), to 30 white, rose, and bottled- and oak-aged red wines, and to 7 commercial dietary antioxidant supplements. All samples exhibited a good linear response with concentration. As seen by other methodologies, the chemical structure of a compound determines its antioxidant activity (ORAC−FL value). Of particular interest were the results with oak-aged red wines from different vintages (1989−2002) that confirm influence of vintage, but not origin of the oak, in the antioxidant activity of wines from the same variety. Dietary antioxidant supplements presented a great variability (170-fold difference) in their antioxidant potency. This work proves applicability of the ORAC−FL assay in evaluating the antioxidant activity of diverse food samples. Keywords: Antioxidant activity; ORAC; fluorescein; phenolics; wine; dietary antioxidant supplements

The aroma of grapes I. Extraction and determination of free and glycosidically bound fractions of some grape aroma components

1985-01-01

Y.Z. Gunata , Claude Bayonove , Raymond Baumes +1 more

The polymeric nature of wine pigments

1971-09-01

T. C. Somers

Metabolite Profiling of Grape: Flavonols and Anthocyanins

2006-09-09

Fulvio Mattivi , Raffaele Guzzon , Urška Vrhovšek +2 more

Flavonols are products of the flavonoid biosynthetic pathway, which also give rise to anthocyanins and condensed tannins in grapes. We investigated their presence in the berry skins of 91 grape … Flavonols are products of the flavonoid biosynthetic pathway, which also give rise to anthocyanins and condensed tannins in grapes. We investigated their presence in the berry skins of 91 grape varieties (Vitis vinifera L.), in order to produce a classification based on the flavonol profile. The presence of laricitrin 3-O-galactoside and syringetin 3-O-galactoside in red grapes is reported here for the first time. In red grapes, the main flavonol was quercetin (mean = 43.99%), followed by myricetin (36.81%), kaempferol (6.43%), laricitrin (5.65%), isorhamnetin (3.89%), and syringetin (3.22%). In white grapes, the main flavonol was quercetin (mean = 81.35%), followed by kaempferol (16.91%) and isorhamnetin (1.74%). The delphinidin-like flavonols myricetin, laricitrin, and syringetin were missing in all white varieties, indicating that the enzyme flavonoid 3',5'-hydroxylase is not expressed in white grape varieties. The pattern of expression of flavonols and anthocyanins in red grapes was compared, in order to gain information on the substrate specificity of enzymes involved in flavonoid biosynthesis. Keywords: Vitis vinifera; grape; flavonols; anthocyanins; flavonoid 3'-hydroxylase; flavonoid 3',5'-hydroxylase; O-methyltransferase

Effect of Solvent, Temperature, and Solvent-to-Solid Ratio on the Total Phenolic Content and Antiradical Activity of Extracts from Different Components of Grape Pomace

2005-02-18

Manuel Pinelo , Mónica Rubilar , María Jerez +2 more

Grape byproducts were subjected to an extraction process under various different experimental conditions (namely, solvent type, temperature, solvent-to-solid ratio, time contact, and raw material) in order to study the effect … Grape byproducts were subjected to an extraction process under various different experimental conditions (namely, solvent type, temperature, solvent-to-solid ratio, time contact, and raw material) in order to study the effect of these conditions on the yield of phenolic compounds and the corresponding antiradical activity of extracts. Although the order of decreasing capacity to extract soluble materials was ethanol > methanol > water, methanol was the most selective for extracting phenolic compounds. Temperature and solvent-to-solid ratio were found to have a critical role in extraction efficiency; values of 50 °C (between 25 and 50 °C) and 1:1 (between 1:1 and 5:1) maximized the antiradical activity of phenolic extracts. In addition, extracts from grape samples previously subjected to distillation reached higher antiradical values in comparison to those coming directly from pressing; in both cases, seed extracts showed better results than those of stem when ethanol or water was employed, whereas the opposite occurred in the case of methanol. These differences were attributed to the different phenolic compositions of the considered fractions. Keywords: Grape (Vitis vinifera); phenolic compounds; extraction; antiradical activity; solvent; temperature

Mass transfer process during extraction of phenolic compounds from milled berries

2003-03-25

J.E. Cacace , Giuseppe Mazza

Upgrading of grape skins: Significance of plant cell-wall structural components and extraction techniques for phenol release

2006-07-25

Manuel Pinelo , Anis Arnous , Anne S. Meyer

Microbe domestication and the identification of the wild genetic stock of lager-brewing yeast

2011-08-22

Diego Libkind , Chris Todd Hittinger , Elisabete Valério +5 more

Domestication of plants and animals promoted humanity's transition from nomadic to sedentary lifestyles, demographic expansion, and the emergence of civilizations. In contrast to the well-documented successes of crop and livestock … Domestication of plants and animals promoted humanity's transition from nomadic to sedentary lifestyles, demographic expansion, and the emergence of civilizations. In contrast to the well-documented successes of crop and livestock breeding, processes of microbe domestication remain obscure, despite the importance of microbes to the production of food, beverages, and biofuels. Lager-beer, first brewed in the 15th century, employs an allotetraploid hybrid yeast, Saccharomyces pastorianus (syn. Saccharomyces carlsbergensis ), a domesticated species created by the fusion of a Saccharomyces cerevisiae ale-yeast with an unknown cryotolerant Saccharomyces species. We report the isolation of that species and designate it Saccharomyces eubayanus sp. nov. because of its resemblance to Saccharomyces bayanus (a complex hybrid of S. eubayanus , Saccharomyces uvarum , and S. cerevisiae found only in the brewing environment). Individuals from populations of S. eubayanus and its sister species, S. uvarum , exist in apparent sympatry in Nothofagus (Southern beech) forests in Patagonia, but are isolated genetically through intrinsic postzygotic barriers, and ecologically through host-preference. The draft genome sequence of S. eubayanus is 99.5% identical to the non- S. cerevisiae portion of the S. pastorianus genome sequence and suggests specific changes in sugar and sulfite metabolism that were crucial for domestication in the lager-brewing environment. This study shows that combining microbial ecology with comparative genomics facilitates the discovery and preservation of wild genetic stocks of domesticated microbes to trace their history, identify genetic changes, and suggest paths to further industrial improvement.

View PDF Chat

Yeasts: Characteristics and identification

1984-10-01

J. F. T. Spencer

Effect of benzoic acid on metabolic fluxes in yeasts: A continuous‐culture study on the regulation of respiration and alcoholic fermentation

1992-07-01

Cornelis Verduyn , Erik Postma , W. A. Scheffers +1 more

Addition of benzoate to the medium reservoir of glucose-limited chemostat cultures of Saccharomyces cerevisiae CBS 8066 growing at a dilution rate (D) of 0.10 h-1 resulted in a decrease in … Addition of benzoate to the medium reservoir of glucose-limited chemostat cultures of Saccharomyces cerevisiae CBS 8066 growing at a dilution rate (D) of 0.10 h-1 resulted in a decrease in the biomass yield, and an increase in the specific oxygen uptake rate (qO2) from 2.5 to as high as 19.5 mmol g-1 h-1. Above a critical concentration, the presence of benzoate led to alcoholic fermentation and a reduction in qO2 to 13 mmol g-1 h-1. The stimulatory effect of benzoate on respiration was dependent on the dilution rate: at high dilution rates respiration was not enhanced by benzoate. Cells could only gradually adapt to growth in the presence of benzoate: a pulse of benzoate given directly to the culture resulted in wash-out. As the presence of benzoate in cultures growing at low dilution rates resulted in large changes in the catabolic glucose flux, it was of interest to study the effect of benzoate on the residual glucose concentration in the fermenter as well as on the level of some selected enzymes. At D = 0.10 h-1, the residual glucose concentration increased proportionally with increasing benzoate concentration. This suggests that modulation of the glucose flux mainly occurs via a change in the extracellular glucose concentration rather than by synthesis of an additional amount of carriers. Also various intracellular enzyme levels were not positively correlated with the rate of respiration. A notable exception was citrate synthase: its level increased with increasing respiration rate. Growth of S. cerevisiae in ethanol-limited cultures in the presence of benzoate also led to very high qO2 levels of 19-21 mmol g-1 h-1. During growth on glucose as well as on ethanol, the presence of benzoate coincided with an increase in the mitochondrial volume up to one quarter of the total cellular volume. Also with the Crabtree-negative yeasts Candida utilis, Kluyveromyces marxianus and Hansenula polymorpha, growth in the presence of benzoate resulted in an increase in qO2 and, at high concentrations of benzoate, in aerobic fermentation. In contrast to S. cerevisiae, the highest qO2 of these yeasts when growing at D = 0.10 h-1 in the presence of benzoate was equal to, or lower than the qO2 attainable at mu(max) without benzoate. Enzyme activities that were repressed by glucose in S. cerevisiae also declined in K. marxianus when the glucose flux was increased by the presence of benzoate.(ABSTRACT TRUNCATED AT 400 WORDS)

View PDF Chat

Function of yeast species and strains in wine flavour

2003-07-31

P. Romano

View PDF Chat

Controlled mixed culture fermentation: a new perspective on the use of non-Saccharomyces yeasts in winemaking

2009-09-05

Maurizio Ciani , Francesca Comitini , Ilaria Mannazzu +1 more

Mixed fermentations using controlled inoculation of Saccharomyces cerevisiae starter cultures and non-Saccharomyces yeasts represent a feasible way towards improving the complexity and enhancing the particular and specific characteristics of wines. … Mixed fermentations using controlled inoculation of Saccharomyces cerevisiae starter cultures and non-Saccharomyces yeasts represent a feasible way towards improving the complexity and enhancing the particular and specific characteristics of wines. The profusion of selected starter cultures has allowed the more widespread use of inoculated fermentations, with consequent improvements to the control of the fermentation process, and the use of new biotechnological processes in winemaking. Over the last few years, as a consequence of the re-evaluation of the role of non-Saccharomyces yeasts in winemaking, there have been several studies that have evaluated the use of controlled mixed fermentations using Saccharomyces and different non-Saccharomyces yeast species from the wine environment. The combined use of different species often results in unpredictable compounds and/or different levels of fermentation products being produced, which can affect both the chemical and the aromatic composition of wines. Moreover, possible synergistic interactions between different yeasts might provide a tool for the implementation of new fermentation technologies. Thus, knowledge of the Saccharomyces and non-Saccharomyces wine yeast interactions during wine fermentation needs to be improved. To reach this goal, further investigations into the genetic and physiological background of such non-Saccharomyces wine yeasts are needed, so as to apply '-omics' approaches to mixed culture fermentations.

Not your ordinary yeast: non-Saccharomycesyeasts in wine production uncovered

2013-10-24

N.P. Jolly , Cristián Varela , Isak S. Pretorius

Saccharomyces cerevisiae and grape juice are 'natural companions' and make a happy wine marriage. However, this relationship can be enriched by allowing 'wild' non-Saccharomyces yeast to participate in a sequential … Saccharomyces cerevisiae and grape juice are 'natural companions' and make a happy wine marriage. However, this relationship can be enriched by allowing 'wild' non-Saccharomyces yeast to participate in a sequential manner in the early phases of grape must fermentation. However, such a triangular relationship is complex and can only be taken to 'the next level' if there are no spoilage yeast present and if the 'wine yeast' - S. cerevisiae - is able to exert its dominance in time to successfully complete the alcoholic fermentation. Winemakers apply various 'matchmaking' strategies (e.g. cellar hygiene, pH, SO2 , temperature and nutrient management) to keep 'spoilers' (e.g. Dekkera bruxellensis) at bay, and allow 'compatible' wild yeast (e.g. Torulaspora delbrueckii, Pichia kluyveri, Lachancea thermotolerans and Candida/Metschnikowia pulcherrima) to harmonize with potent S. cerevisiae wine yeast and bring the best out in wine. Mismatching can lead to a 'two is company, three is a crowd' scenario. More than 40 of the 1500 known yeast species have been isolated from grape must. In this article, we review the specific flavour-active characteristics of those non-Saccharomyces species that might play a positive role in both spontaneous and inoculated wine ferments. We seek to present 'single-species' and 'multi-species' ferments in a new light and a new context, and we raise important questions about the direction of mixed-fermentation research to address market trends regarding so-called 'natural' wines. This review also highlights that, despite the fact that most frontier research and technological developments are often focussed primarily on S. cerevisiae, non-Saccharomyces research can benefit from the techniques and knowledge developed by research on the former.

Microbial biogeography of wine grapes is conditioned by cultivar, vintage, and climate

2013-11-25

Nicholas A. Bokulich , J.H. Thorngate , Paul M. Richardson +1 more

Wine grapes present a unique biogeography model, wherein microbial biodiversity patterns across viticultural zones not only answer questions of dispersal and community maintenance, they are also an inherent component of … Wine grapes present a unique biogeography model, wherein microbial biodiversity patterns across viticultural zones not only answer questions of dispersal and community maintenance, they are also an inherent component of the quality, consumer acceptance, and economic appreciation of a culturally important food product. On their journey from the vineyard to the wine bottle, grapes are transformed to wine through microbial activity, with indisputable consequences for wine quality parameters. Wine grapes harbor a wide range of microbes originating from the surrounding environment, many of which are recognized for their role in grapevine health and wine quality. However, determinants of regional wine characteristics have not been identified, but are frequently assumed to stem from viticultural or geological factors alone. This study used a high-throughput, short-amplicon sequencing approach to demonstrate that regional, site-specific, and grape-variety factors shape the fungal and bacterial consortia inhabiting wine-grape surfaces. Furthermore, these microbial assemblages are correlated to specific climatic features, suggesting a link between vineyard environmental conditions and microbial inhabitation patterns. Taken together, these factors shape the unique microbial inputs to regional wine fermentations, posing the existence of nonrandom "microbial terroir" as a determining factor in regional variation among wine grapes.

View PDF Chat

Tailoring wine yeast for the new millennium: novel approaches to the ancient art of winemaking

2000-01-01

Isak S. Pretorius

Yeasts are predominant in the ancient and complex process of winemaking. In spontaneous fermentations, there is a progressive growth pattern of indigenous yeasts, with the final stages invariably being dominated … Yeasts are predominant in the ancient and complex process of winemaking. In spontaneous fermentations, there is a progressive growth pattern of indigenous yeasts, with the final stages invariably being dominated by the alcohol-tolerant strains of Saccharomyces cerevisiae. This species is universally known as the 'wine yeast' and is widely preferred for initiating wine fermentations. The primary role of wine yeast is to catalyze the rapid, complete and efficient conversion of grape sugars to ethanol, carbon dioxide and other minor, but important, metabolites without the development of off-flavours. However, due to the demanding nature of modern winemaking practices and sophisticated wine markets, there is an ever-growing quest for specialized wine yeast strains possessing a wide range of optimized, improved or novel oenological properties. This review highlights the wealth of untapped indigenous yeasts with oenological potential, the complexity of wine yeasts' genetic features and the genetic techniques often used in strain development. The current status of genetically improved wine yeasts and potential targets for further strain development are outlined. In light of the limited knowledge of industrial wine yeasts' complex genomes and the daunting challenges to comply with strict statutory regulations and consumer demands regarding the future use of genetically modified strains, this review cautions against unrealistic expectations over the short term. However, the staggering potential advantages of improved wine yeasts to both the winemaker and consumer in the third millennium are pointed out.

Evaluation of the Key Odorants of Foods by Dilution Experiments, Aroma Models and Omission

2001-06-01

Werner Grosch

The state of the art in aroma analysis is reviewed with emphasis on aroma-recombination studies using synthetic blends of odorants (aroma models) which have been prepared on the basis of … The state of the art in aroma analysis is reviewed with emphasis on aroma-recombination studies using synthetic blends of odorants (aroma models) which have been prepared on the basis of analytical data. The model that matches the original aroma is the starting material for omission experiments which are performed to establish the odorants that actually contribute to the aroma. These experiments are discussed in detail for the aromas of two wine varieties, three olive oils of different provenance, French fries, boiled beef and coffee. The results indicate that odorants with higher odour activity values (OAV, the ratio of the concentration to the odour threshold) are frequently essential for the aroma. However, there are exceptions where odorants with high OAVs are suppressed in the aroma and compounds with lower OAVs are important contributors. These findings are discussed in the light of model experiments which have been reported in the literature to obtain an insight into the perceptual interactions of odorants in mixtures.

Yeast: the soul of beer’s aroma—a review of flavour-active esters and higher alcohols produced by the brewing yeast

2014-01-02

Eduardo Pires , J. A. Teixeira , Tomáš Brányik +1 more

View PDF Chat

Wine flavor and aroma

2011-07-23

Gustav Styger , Bernard A. Prior , Florian F. Bauer

View PDF Chat

The Copigmentation of Anthocyanins and Its Role in the Color of Red Wine: A Critical Review

2001-01-01

Roger B. Boulton

Copigmentation is a solution phenomenon in which pigments and other noncolored organic components form molecular associations or complexes. It generally results in an enhancement in the absorbance and in some … Copigmentation is a solution phenomenon in which pigments and other noncolored organic components form molecular associations or complexes. It generally results in an enhancement in the absorbance and in some cases, a shift in the wavelength of the maximum absorbance of the pigment. Copigmentation has not previously been taken into account in traditional wine color measures, in the relationship between color and pigment analysis, or in spectrophotometric assays for anthocyanin content. It is now apparent that copigmentation can account for between 30 and 50% of the color in young wines and that it is primarily influenced by the levels of several specific, noncolored phenolic components or cofactors. Copigmentation is of critical importance in understanding the relationship between grape composition and wine color, the variation in color and pigment concentration between wines, and in all reactions involving the anthocyanins during wine aging. This review focuses on the importance of the individual pigments and cofactors, the strength of their interactions, and their relative abundance in grapes and wines. A simple mathematical analysis of the solution equilibrium is developed to explain the nonlinear deviation from Beer’s law. When solved for typical wines, this function provides estimates of the apparent association constant, K, and the apparent molar extinction of the copigmented form, Ec, in natural mixtures. These measures allow the fraction of the anthocyanins which is in the copigmented form to be estimated. The significance of this phenomenon on pigment extraction and color retention during fermentations, on the rate of subsequent pigment polymerization, on the possible protection of anthocyanins from oxidation, and in the possible involvement on perceived mouthfeel and astringency of wines are suggested. Aspects of the copigmentation phenomenon that are poorly understood are identified and some research directions are suggested.

Population genomics of domestic and wild yeasts

2009-02-11

Gianni Liti , David M. Carter , Alan M Moses +7 more

View PDF Chat

Total Phenol Analysis: Automation and Comparison with Manual Methods

1977-01-01

Karen Slinkard , Vernon L. Singleton

A fully automated-continuous flow 40-sample/ hour procedure was adapted from the Singleton-Rossi method of analysis for total phenols in wine and other plant extracts. It was compared with small-volume manual … A fully automated-continuous flow 40-sample/ hour procedure was adapted from the Singleton-Rossi method of analysis for total phenols in wine and other plant extracts. It was compared with small-volume manual and semiautomated versions of this analysis. The agreement in mg of gallic acid equivalent phenol (GAE) per liter among a series of dry wines was excellent by all three procedures. The coefficients of variation in replicate analyses averaged 5.8% for the manual, 6.2% for the semi-automated and 2.2% for the automated procedure. This greater reproducibility, plus savings of about 70% in labor and up to 40% in reagents, makes the automated procedure attractive for laboratories doing enough total phenol analyses to recoup the cost of the automating equipment. For continuous flow, color development with the Folin-Ciocalteu reagent in alkaline solution must be hastened by heating compared to slower room temperature development for the manual methods. Heating of sugar-containing samples in the alkaline solution gives interference presumably from endiol formation. Examples are given of corrections which were used successfully to estimate the true phenol content of sweet wines.

Oxygen with Phenols and Related Reactions in Musts, Wines, and Model Systems: Observations and Practical Implications

1987-01-01

Vernon L. Singleton

A review with 45 references of the title topic is presented emphasizing research by the author9s associates. Con- clusions and their bases are outlined with comments on their significance to … A review with 45 references of the title topic is presented emphasizing research by the author9s associates. Con- clusions and their bases are outlined with comments on their significance to winemakers. Recent findings with regard to products of enzymic must oxidation and forced oxidation of phenols are discussed with their practical implications.

Domestication and Divergence of Saccharomyces cerevisiae Beer Yeasts

2016-09-01

Brigida Gallone , Jan Steensels , Troels Prahl +7 more

View PDF Chat

Mystery behind Chinese liquor fermentation

2017-03-02

Guangyuan Jin , Yang Zhu , Yan Xu

Chinese liquor, a very popular fermented alcoholic beverage with thousands of years’ history in China, though its flavour formation and microbial process have only been partly explored, is facing the … Chinese liquor, a very popular fermented alcoholic beverage with thousands of years’ history in China, though its flavour formation and microbial process have only been partly explored, is facing the industrial challenge of modernisation and standardisation for food quality and safety as well as sustainability. Meanwhile, the hidden knowledge behind the complicated and somehow empirical solid-state fermentation process of Chinese liquor can enrich the food sector to improve our quality of life, and benefit other industrial sectors in the modern biomass-based technology, economy and society. This review reveals the traditional fermentation process and characteristics of Chinese liquor, summarises the current study progress of flavour chemistry and responsible microbial process, and addresses future improvement and research needs. We provide here a detailed, systematic and critical review on Chinese liquor to improve the current industrial practice and serve the modern society with yet incompletely explored but useful principles. The hidden knowledge behind the traditional Chinese liquor production is rich in useful principles including flavour chemistry, microbial growth, solid-state fermentation, enzyme production, biocatalysis, microbial community metabolism and process engineering. Studies in a more in-depth, systematic and practical way on this look-like empirical process to explore the scientific principles behind will definitely benefit the liquor industry in particular, and the (food) biotechnology sector in general.

Effect of Fermentation Processing on the Flavor of Baijiu

2018-05-11

Huilin Liu , Baoguo Sun

Baijiu, otherwise known as the national liquor of China, is a well-known distilled spirit that has been produced for over 2000 years. Baijiu is a clear and transparent fermented alcoholic … Baijiu, otherwise known as the national liquor of China, is a well-known distilled spirit that has been produced for over 2000 years. Baijiu is a clear and transparent fermented alcoholic beverage containing more than 1870 volatile compounds, including esters, alcohols, aromatics, ketones, heterocycles, nitrogenous compounds, acids, aldehydes, terpenes, sulfur compounds, acetals, and lactones. This perspective describes the baijiu production process, summarizes recent progress in the development and study of baijiu flavor chemistry, discusses the effect of fermentation processing on baijiu flavor, and presents novel development trends in the baijiu industry in the dual directions of flavor and health. Furthermore, the direction of research and development for modernization in the baijiu industry is discussed and proposed.

Total Phenol Analysis: Automation and Comparison with Manual Methods

1977-01-01

Karen Slinkard , Vernon L. Singleton

Kinetics of product inhibition in alcohol fermentation

1968-11-01

Setsuya Aiba , Munehito Shoda , M. Nagatani

Abstract The inhibitory effect of ethanol concentration p in a medium on the specific rates of growth μ and ethanol production ν of a specific strain of baker's yeast was … Abstract The inhibitory effect of ethanol concentration p in a medium on the specific rates of growth μ and ethanol production ν of a specific strain of baker's yeast was studied in a chemostat, where except for ethanol as the product, only the concentration of glucose S was controlled to limit the metabolic activity of the yeast. This was designed to supplement the previous findings from the batch experiment, in which ethanol was added artificially and no substrate components were limiting the metabolism of the same yeast, that μ = μ 0 e and ν = ν 0 e , where k 1 and k 2 are empirical constants and subscript the 0 denotes respective values at p = 0. The effects of p on the values of μ and ν were confirmed by the Lineweaver‐Burk plot to belong to noncompetitive inhibition. The formulas here for μ and ν as affected by p , if extrapolated to the case of no limiting substrates, were in good agreement in respective forms with those derived previously from the batch experiment, though the values of corresponding coefficients in these formulas were different. The differential equations for μ and ν as functions of both p and S and, in addition for the rate of glucose consumption as correlated by the yield factors either with the cell growth rate or the rate of ethanol production, were solved properly with a digital computer. A kinetic, pattern calculated so far was discussed with reference to the data obtained in the batch experiment and those relevant to actual “sake” brewing.

Wine Chemistry and Biochemistry

2008-11-05

M. Victoria Moreno‐Arribas , M. Carmen Polo

Exploring the Impact of Dinotefuran Residue on Microbial Community and Flavor Generation in Huangjiu Fermentation

2025-06-24

Shanshan Zhao , Qisi Xu , Minmin Li +5 more | Journal of Agricultural and Food Chemistry

Pesticide residues create food safety hazards while negatively affecting the quality of fermented foods, but the mechanisms of the deterioration response have been a mystery. In this study, headspace solid-phase … Pesticide residues create food safety hazards while negatively affecting the quality of fermented foods, but the mechanisms of the deterioration response have been a mystery. In this study, headspace solid-phase microextraction gas chromatography-mass spectrometry (HS-SPME-GC-MS) and metagenomics sequencing analyses were employed to investigate the effect of dinotefuran residue on the aroma profile and microbial community of Huangjiu. The presence of dinotefuran led to a reduction in the overall concentration of volatile compounds, and some floral, fruity, and sweet aromas such as piperitenol, citronellyl isobutyrate, and trans-2-decenal were no longer detected. Meanwhile, the levels of certain acidic volatiles, including formic acid, propionic acid, and heptanoic acid, increased and contributed to off-flavors. Dinotefuran affected the Huangjiu flavor by modifying the abundance and structure of key genera such as Saccharomyces, Lactococcus, and Cyberlindnera. These changes were associated with disturbances in 16 KEGG tertiary metabolic pathways, including glycolysis, pyruvate metabolism, and amino acid biosynthesis. These results provided some reference for further studies on how pesticide residues affect the flavor and microbial characteristics of traditional fermented beverages like Huangjiu.

Discrimination of Smoke-Exposed Pinot Noir Wines by Volatile Phenols and Volatile Phenol-Glycosides

2025-06-24

Armando Alcázar Magaña , Ruiwen Yang , Michael C. Qian +1 more | Molecules

This study investigated the correlation between five primary volatile phenols (VPs) and their glycosides in smoke-exposed and non-smoke-exposed Pinot noir wines to assess and identify potential markers for smoke taint. … This study investigated the correlation between five primary volatile phenols (VPs) and their glycosides in smoke-exposed and non-smoke-exposed Pinot noir wines to assess and identify potential markers for smoke taint. The results showed that all putative VP-glycosides in smoke-exposed wines were higher than in non-smoke-exposed wines, with a fold change ranging from 2.11 to 31.88 for the top fifteen differentiations. VP-glycosides showed strong positive correlations among themselves, with correlation coefficients of 0.94 for hexose-guaiacol vs. pentose (P)-hexose (H)-cresol and 0.92 for syringyl-β-D-glucopyranoside vs. H-P-4-methylguaiacol. VP-glycosides also showed relatively high correlations with free and strong acid-hydrolyzed VPs. The correlation coefficient between H-P-guaiacol and free-form guaiacol is 0.71, and between H-P-guaiacol and total guaiacol is 0.78. The strong correlation suggests that these compounds are interconnected and regulated by the severity of smoke exposure. Multivariate analysis effectively differentiated smoke-exposed wines from non-smoke-exposed ones. However, more research is needed to fill the gaps in understanding smoke-derived compounds.

Odorant capture-and-release in polymer cavities: Implications for red wine aroma from simulations on model wine solutions

2025-06-22

Tobias Koch , Anna Maria Gabler , Johanna Kreißl +3 more | Molecular Simulation

Maltose and Maltotriose Transporters in Brewer’s Saccharomyces Yeasts: Polymorphic and Key Residues in Their Activity

2025-06-20

Oscar A. Faz-Cortez , Jorge H. García-García , Ana K. Carrizales-Sánchez +5 more | International Journal of Molecular Sciences

Maltose and maltotriose are the most abundant sugars in brewing wort, and their transport represent a critical bottleneck in the fermentation process. This transport relies on specific transmembrane proteins; however, … Maltose and maltotriose are the most abundant sugars in brewing wort, and their transport represent a critical bottleneck in the fermentation process. This transport relies on specific transmembrane proteins; however, many yeast strains exhibit inefficient uptake of these sugars, particularly maltotriose. Addressing this limitation requires a comprehensive understanding of the factors influencing the transport of maltose and maltotriose. This review provides a detailed synthesis of the key characteristics and functions of the maltose and maltotriose transmembrane transporters identified in brewer’s Saccharomyces yeasts. Critical amino acid residues involved in transporter activity are also highlighted, and the impact of specific polymorphisms and sequence variations on sugar preference and uptake efficiency is examined. Furthermore, a thorough discussion of the most important reported residues is presented, underscoring the need to closely examine their amino acid composition to better understand transporter mechanisms, optimize their performance, and enhance fermentation outcomes.

Assessment of the Sensory Properties of Wines Using Artificial Intelligence Technologies

2025-06-20

А. А. Khalafyan , З. А. Темердашев , A. G. Abakumov +2 more | ACS Food Science & Technology

Refining the craft of sour beers: a journey through fermentation, tartness and regional nuances

2025-06-19

Amanda Felipe Reitenbach , Grace Ferreira Ghesti , Adriana Sturion Lorenzi +7 more | European Food Research and Technology

Study on stress treatment process and its mechanism of baijiu yeast before drying

2025-06-19

Fengkui Xiong , Zhongbin Liu , Jingyu Li +3 more | Research Square (Research Square)

<title>Abstract</title> Aiming at the problems of low survival rate and unclear mechanism of stress treatment of <italic>Modified Jowett's spore A</italic> (MSJA) during drying. Firstly, response surface methodology was designed to … <title>Abstract</title> Aiming at the problems of low survival rate and unclear mechanism of stress treatment of <italic>Modified Jowett's spore A</italic> (MSJA) during drying. Firstly, response surface methodology was designed to optimize the stress treatment process of MSJA in order to improve the survival rate of spray drying. Then, with the help of high-resolution field emission scanning electron microscope (FESEM) observation, the effect strength and influence mechanism of each stress treatment process were explored. The results showed that the survival rate of MSJA could be increased from 38.5% to 54.8% under the typical conditions of heat shock temperature (<italic>X</italic>)=35.2 ℃, acid stress pH (<italic>Y</italic>)=3.2, and KH2PO4 concentration (<italic>Z</italic>)=4 g/L. From comprehensive treatment → heat shock → acid stress → salt stress, the protective effect decreased in turn. The reason is that the diameter, morphology and smoothness of cell wall of MSJA treated by the above stress decreased after spray drying.

Network-based insights into the temperature-driven mechanisms of bacterial self-assembly in the solid-state fermented vinegar seed Pei

2025-06-19

Mingchao Jiang , Yiyang Zou , Yuhang Wang +7 more | Food Bioscience

Thermal processing modulates starch and non-starch macromolecules digestibility in chestnut: Structural reconfiguration and molecular interactions

2025-06-18

Xueying Gao , Junwei Yuan , Bin Du +5 more | International Journal of Biological Macromolecules

Suitability of indigenous Saccharomyces cerevisiae strains isolated from spontaneous fermentations as wine fermentation starter cultures in the Okanagan Valley wine region in Canada

2025-06-18

Erick Castellanos , Joana Pico , Jackson Moore +4 more | OENO One

Winemaking from grape juice is typically carried out using the Saccharomyces cerevisiae (S. cerevisiae) yeast species as a starter culture for ethanolic fermentation. The specific S. cerevisiae strain performing the … Winemaking from grape juice is typically carried out using the Saccharomyces cerevisiae (S. cerevisiae) yeast species as a starter culture for ethanolic fermentation. The specific S. cerevisiae strain performing the fermentation plays a key role in shaping the aroma profile of the wine. Commercially available strains of S. cerevisiae improve the reproducibility and predictability of wine by establishing well-controlled fermentations. However, indigenous S. cerevisiae strains may be better acclimated to the conditions of a particular wine producing region and may enhance the sensory properties and characteristic profiles of the wine. This work assesses the oenological performance of S. cerevisiae strains isolated from the Okanagan Valley wine region in Canada in laboratory and pilot-scale fermentations. Six indigenous S. cerevisiae strains isolated from spontaneous fermentations at Okanagan Crush Pad (OCP) winery were selected for this research. Pinot gris and Pinot noir grape juice was used to perform 250 mL lab-scale fermentations carried out at 20 °C and 25 °C, respectively. Primary metabolites were quantified by high pressure liquid chromatography coupled to a refractive index detector (HPLC-RID) and volatile compounds were quantified by solid phase microextraction coupled to gas chromatography and mass spectrometry (SPME-GC/MS). Lab-scale Pinot gris wines produced with OCP indigenous strains had higher concentrations of the ester ethyl butanoate (apple, pineapple aroma) than lab-scale wines fermented with a commercial strain. OCP-088 and OCP-125 strains were selected for OCP winery pilot-scale fermentations in 250 L stainless steel barrels with Pinot gris and Pinot noir juice during the 2022 harvest. Both OCP strains persisted throughout the fermentations. Residual sugars were identified in both wines, primarily consisting of fructose at a range of 16-22 g/L and the alcohol by volume of the finished wine ranged from 10.82-11.58 %. Pilot-scale wines produced with OCP-088 and OCP-125 strains had a similar aroma composition, producing an off-dry wine with a desirable fruity aroma bouquet that had a higher concentration of the ester ethyl decanoate (sweet, fruity aroma) than commercial wines fermented in the same vintage. This study indicates that Okanagan indigenous strains ferment wines with desirable aromatic profiles and may be suitable as starter-cultures for producing wine reflective of the region.

Dynamic interplay between core functional microbial succession and flavor metabolite formation in naturally fermented sufu: A multi-omics perspective

2025-06-18

Chen Chen , Jia‐Ming Li , Zahoor Ahmed +4 more | Food Bioscience

Polyphenols from Winery by-products: Conventional versus Unconventional Extraction Methodologies

2025-06-18

Rui Dias-Costa , Marta Coelho , Raúl Domínguez‐Perles +2 more | IntechOpen eBooks

A large number of studies have already demonstrated that winery by-products (WBPs) are a valuable source of natural antioxidants, especially due to their phenolic content. These residues can be reused … A large number of studies have already demonstrated that winery by-products (WBPs) are a valuable source of natural antioxidants, especially due to their phenolic content. These residues can be reused as new ingredients in the food, cosmetic, and pharmaceutical industries. For that reason, a scientific foundation for the comprehension of extraction methods’ efficiency is essential for starting the reuse of these by-products on a large scale. Numerous phenolic compounds extraction techniques under different conditions are currently being investigated. There has been a growing scientific interest in these phytochemicals, driven by the adoption of more eco-friendly extraction techniques that facilitate higher extraction yields. To extract the phenolic compounds present in WBPs, conventional methods as well as nonconventional extraction methods can be employed. The first ones, which have been used for a very long period, include Soxhlet extraction, maceration, reflux extraction, and others. Nonconventional methods, widely recognized as eco-friendly methods, such as ultrasound-assisted extraction (UAE), microwave-assisted extraction (MAE), accelerated solvent extraction (ASE), and supercritical extraction (SE), among others, provide higher extraction yields and high-quality extracts. This chapter will explore the extraction methodologies of phenolic compounds from WBPs produced by the wine industry, with a focus on both conventional and unconventional techniques. Additionally, the grape varieties mentioned in this review are suitable for production in Portugal under Designation of Origin (DO) and Geographical Indication (GI) classifications.

Evaluating the Chemical Composition and Sensory Attributes of Japanese and U.S. Sake

2025-06-18

Rahul Sen , Kevin Hope , Ben Bell +1 more | ACS Food Science & Technology

Filtration Challenges in Non-Alcoholic and Low-Alcohol Beer Production with a Focus on Different Yeast Strains

2025-06-17

Christian Schubert , Jörg Maxminer , Matthew S. Aitkens +4 more | Applied Sciences

This study examines the impact of yeast selection on fermentation performance, filtration efficiency, and the stability of low-alcohol and non-alcoholic beer (NAB). Three yeast strains (LA-01, LoNa, and W-34/70) were … This study examines the impact of yeast selection on fermentation performance, filtration efficiency, and the stability of low-alcohol and non-alcoholic beer (NAB). Three yeast strains (LA-01, LoNa, and W-34/70) were evaluated for their effects on key NAB parameters like ABV, bitterness, color, haze readings, and filtration-linked performance. Filtration trials revealed that highly flocculating W-34/70 resulted in lower post-filtration turbidity, whereas LA-01 and LoNa (which flocculated less) required more effective filtration techniques to achieve clarity. Among the tested filter sheets, AF 31, AF 71, and AF 101 successfully reduced turbidity below 2 EBC. However, all NABs exhibited haze formation during storage, indicating the necessity of stabilization treatments. These findings highlight the importance of yeast strain selection and filtration strategies in optimizing NAB production. Additional pretreatment steps, such as centrifugation, may improve filterability for non-flocculating yeasts, while stabilization measures are essential for maintaining long-term clarity. This study provides valuable insights for improving industrial NAB processing and quality.

Composition Divergence and Synergistic Mechanisms in Microbial Communities During Multi-Varietal Wine Co-Fermentation

2025-06-16

Yuhan Zhang , Jiao Yang , Yuxi Yan | Fermentation

The bacterial microbial community composition during wine fermentation is a key contributor to wine quality and flavor. However, studies on the regulatory effects of different grape varieties and co-fermentation processes … The bacterial microbial community composition during wine fermentation is a key contributor to wine quality and flavor. However, studies on the regulatory effects of different grape varieties and co-fermentation processes on the microbial community structure and their synergistic mechanisms remain limited. In this study, Cabernet Sauvignon (CS) was subjected to single-variety fermentation and used as the base wine for co-fermentation with three other grape varieties—Marselan (CSMN), Merlot (CSMT), and Cabernet Gernischt (CSCG)—to systematically compare the differences in the microbial community composition and their effects on the production of metabolic compounds. The results showed that, compared with single-variety fermentation, co-fermentation significantly increased the α-diversity of microbial communities (the Shannon index increased) and exhibited significant differences in β-diversity (PERMANOVA analysis, R2 = 0.421, p < 0.001). A neutral model analysis indicated that co-fermentation had a significant impact on microbial community assembly mechanisms, with the contribution of neutral processes to community assembly increasing from 45.5% (in the CSCG process) to 62.3% (in the CSMT process). A microbial co-occurrence network analysis revealed that co-fermentation enhanced the network complexity of microbial communities and strengthened the synergistic interactions between microbial taxa. A metabolic compound analysis revealed that co-fermentation significantly enhanced the production of key aroma compounds, resulting in increased concentrations of isoamyl acetate, ethyl hexanoate, linalool, and geraniol. These findings highlight the differences in microbial communities and their synergistic mechanisms among co-fermented grape varieties, providing theoretical guidance and practical insights for optimizing co-fermentation processes and improving wine quality.

Flavoromics analysis and sensory evaluation of wines produced from nine red grape cultivars in Manas region, Xinjiang, China: Implications for terroir adaptation

2025-06-16

Ning Shi , Yifan Zhao , Hao-Cheng Lu +7 more | Food Chemistry

Iberian Peninsula as a model context for the application of emerging non-thermal technologies and microbial biotechnologies used in sustainable wine processing

2025-06-16

António Morata , Carlos Escott , Juan Manuel del Fresno +7 more | Critical Reviews in Food Science and Nutrition

The sustainable transition of wine production systems includes non-thermal technologies, microbial biotechnologies and nature-inspired solutions. The Iberian Peninsula is a significant global wine producer, with unique geography and a strong … The sustainable transition of wine production systems includes non-thermal technologies, microbial biotechnologies and nature-inspired solutions. The Iberian Peninsula is a significant global wine producer, with unique geography and a strong R&D context, making it an interesting model for global trends. Spain and Portugal serve as models for using these novel technologies to reduce the environmental footprint. Emerging non-thermal technologies are of interest in the food industry, and currently, many applications have been proposed in the wine industry. These tools can process grapes or grape must to enhance the extraction of phenols, aroma compounds, and nutrients, eliminate wild microorganisms, and control deletereous enzymes. High Hydrostatic Pressure, Ultra High-Pressure Homogenization, Ultrasounds, and Pulsed Electric Fields are approved by the OIV for grape, juice, or wine treatments. Other technologies, like UV-C, are under evaluation. These methods may reduce wild microbiota and aid in starter culture implantation, supporting bio-based applications. Traditional fermentations with Saccharomyces cerevisiae have evolved to include non-Saccharomyces and malolactic bacteria in mixed cultures, reducing the use of exogenous chemicals like SO2. The approaches given in this work not only support environmental sustainability but also enhances the overall quality and safety of wine, making it a valuable contribution to the industry.

Obtaining new brewing yeasts using regional Chilean wine yeasts through an adaptive evolution program

2025-06-16

Ángela Contreras , Manuel Villalobos-Cid , Cristián Valdés +4 more | Frontiers in Microbiology

Beer consumption has increased worldwide, positioning it as the most consumed alcoholic beverage on the market. Saccharomyces cerevisiae brewing yeasts have specific genetic characteristics that allow them to survive in … Beer consumption has increased worldwide, positioning it as the most consumed alcoholic beverage on the market. Saccharomyces cerevisiae brewing yeasts have specific genetic characteristics that allow them to survive in malt wort using maltose and maltotriose as the principal carbon source. However, metabolizing these sugars is challenging for non-brewery Saccharomyces strains under typical brewing conditions, which involve high osmotic stress and low temperatures. These conditions restrict beer producers to a limited range of yeast strains, increasing their cost and contributing to beer flavors uniformity. Here, we performed an adaptive evolution process to improve the fermentative capacities of S. cerevisiae winemaking yeasts isolated from Chilean vineyards to allow their use in brewing. Initially, we screened 50 strains of viticultural origin collected from different areas of Chile. Five strains were selected based on their fermentative capacities, sugar consumption, flavor and aroma, after which were subjected to an adaptive evolution process of 600 generations. We obtained an evolved strain that was able to consume maltose and maltotriose, growing in very high gravity wort (29°P) and at low temperatures (18°C) without shaking. We used DNA sequencing to examine genome changes that could explain the superior beermaking phenotype of the evolved strain. We found that the evolved strain completely lost a parental genome and showed aneuploidies, resulting in gene copy number variations. Interestingly, duplications in genes related to maltose metabolism ( IMA1 , MAL13 and MAL11 ) were observed. Moreover, we also found 160 genes that lost a copy in the evolved strain, of which three showed complete loss: FLO5 , PAU 8, and SEO1 . These genes are related to wine yeast survival under the stress conditions of grape must (lower pH, higher glucose and ethanol concentration than wort). Our results show a successful application of high stress levels to evolve regional winemaking strains to improve their fermentative traits for the brewing process. Applying this method will make it possible to obtain yeasts that can carry out alcoholic fermentation in wort without having to buy unique strains called “brewing yeasts.”

Classification of the geographical origin of pinot noir wines from southwestern Switzerland using isotopes, volatile organic compounds, and chemometrics

2025-06-16

Jorge E. Spangenberg , J. Baumann , Vivian Zufferey | Food Chemistry

This study examined the potential of carbon and nitrogen isotopes of wine solid residues with semi-quantitative amounts of volatile organic compounds to characterize Pinot noir wines from different regions in … This study examined the potential of carbon and nitrogen isotopes of wine solid residues with semi-quantitative amounts of volatile organic compounds to characterize Pinot noir wines from different regions in southwestern Switzerland. Significant differences in the 13C/12C (-30.6 to -26.4 mUr), 15N/14N (0.6-6.7 mUr), C/N (25-102), and contents of 38 volatiles exist between the wines. Principal component analysis identified three distinct clusters of wine regions: Valais, southern Vaud-Geneva, and Three Lakes. These clusters corresponded to a gradient in altitude, precipitation, temperature, and air humidity. The wine samples were satisfactorily classified according to their geographical origin using linear discriminant analysis on isotopic and molar ratios (84.8 % accurate prediction), selected volatile compounds (90.9 % accurate prediction), and the combination of both (95.5 % accurate prediction). Soil factors and aging in oak barrels did not affect the ability to classify wines based on the isotopic ratios and semi-quantified volatile compounds.

Fermentation kinetics, physicochemical properties, and antioxidant activity of Fuji apple cider fermented with different yeast strains

2025-06-16

Xinyan Peng , Yunying Li , Nan Li +3 more | Food Research International

Chemical Traits and Microbial Population Characterization of ‘Asprinio’ Grape Must, a Local Vine Cultivated in Campania Region (Italy)

2025-06-16

Nicola Landi , Monica Scognamiglio , Lidia Muscariello +7 more | Foods

'Asprinio' grape is used to produce a white wine from the Campania region, known as 'Asprinio' (DOC since 1993). A plethora of approaches was adopted to characterize the organic compounds … 'Asprinio' grape is used to produce a white wine from the Campania region, known as 'Asprinio' (DOC since 1993). A plethora of approaches was adopted to characterize the organic compounds (e.g., free amino acids and other metabolites) and microbial population (bacteria and fungi) in 'Asprinio' grape must by collecting samples from three different vineyards cultivated with the 'alberata' training system. The average free amino acid content of 'Asprinio' grape must showed quantitative variations, but no significant statistical differences were found. On average, proline was the most abundant free amino acid (~282 mg/L; 47.9%), followed by arginine (~66 mg/L; 11.5%) and glutamine (~25.2 mg/L; 4.2%). On the other hand, the total polyphenol content (TPC) of 'Asprinio' grape must was different, like their antioxidant activity, which increased when the TPC content was higher. Moreover, 1D and 2D NMR spectra highlighted the presence of high sugars amount (in particular glucose) as well as trans-caftaric acid, trans-coutaric acid, trans-fertaric acid, and the cis-isomers of these cinnamate esters. Finally, the evaluation of the microbial communities in the 'Asprinio' grape must revealed the presence of several representative bacterial phyla-mainly Bacteroidota, Proteobacteria, and Actinobacteriota-as well as various fungal genera, including Cladosporium, Hanseniaspora, Aspergillus, and Saccharomyces. Notably, these microorganisms, which contribute to the fermentation process and influence the final wine flavor, have been found in different proportions in the grape musts analyzed. Our results contribute to increasing knowledge of the 'Asprinio' grape, an indigenous vine of Southern Italy.

NIR spectroscopy for predicting the aroma potential of intact tempranillo grape berries during ripening

2025-06-16

Sandra Marín‐San Román , María P. Diago , Juan Fernández‐Novales +3 more | European Food Research and Technology

Effect of Different Gelling Agents on the Properties of Wine Jellies Prepared from Aromatic Grape Varieties

2025-06-15

Radek Sotolář , Petr Bača , Vladimír Mašán +4 more | Processes

Wine jelly is regarded as a delicacy in many countries and is commonly utilized in grande cuisine. Recently, its popularity has increased among consumers due to its dietary properties and … Wine jelly is regarded as a delicacy in many countries and is commonly utilized in grande cuisine. Recently, its popularity has increased among consumers due to its dietary properties and the presence of health-promoting compounds such as antioxidants. Its natural origin and the ability to reflect local traditions and consumer preferences further enhance its appeal. This study aimed to compare the compositional and sensory characteristics of wine jellies prepared using three different gelling agents and four aromatic grape varieties, with the goal of preserving varietal aroma in the final products. White wines from Pálava and Moravian Muscat and red wines from Agni and Rosa were used. The selected gelling agents were agar, vegan gelatin, and traditional gelatin. Basic analytical parameters were assessed in both the wines and the resulting jellies. Sensory evaluation was conducted by trained panelists, assessing consistency, appearance (clarity), taste, and bouquet. Confectionery-grade jelly from red wines demonstrated the best consistency, while gelatin jellies from white wines showed superior clarity. Due to a preference for sweeter flavors, jellies from red wines were favored across all variants. The strongest varietal bouquet was observed in Moravian Muscat samples, irrespective of the gelling agent used. The optimal choice of gelling agent depends on the target quality attributes. Gelatin is preferred for firmness and clarity, while vegan gelatin is ideal for preserving aroma and achieving a balanced sensory profile.

Long term compositional profiling of historical tokaji aszú wines

2025-06-14

Ágota Ragyák , Zsófi Sajtos , Edina Baranyai +1 more | npj Science of Food

Abstract This study examines the elemental composition of unique Tokaji aszú wines produced between 1999 and 2019, representing the longest period for this wine type to date. Twenty-one samples were … Abstract This study examines the elemental composition of unique Tokaji aszú wines produced between 1999 and 2019, representing the longest period for this wine type to date. Twenty-one samples were analyzed using ICP-OES and FTIR techniques. Multivariate statistical analysis revealed significant variations linked to vintage, annual precipitation, sunshine hours, and temperature. Potassium and chromium levels showed strong negative correlations with age, while calcium exhibited a slight increasing trend. FTIR analysis highlighted compositional differences driven by environmental factors, with PCA clustering vintages based on similar weather patterns. These findings emphasize the influence of environmental conditions on the elemental profile of aged aszú wines, offering insights into historical agricultural practices and environmental shifts. The study underscores the value of long-term wine analysis for understanding climate impacts, optimizing future wine production, and preserving the heritage of traditional viticulture. It highlights elemental profiling as a promising tool for historical analysis, environmental assessment, and sustainable viticultural planning.

Dough Rising Capacity of a Novel Yeast Yarrowia Phangngaensis Isolated from Palmwine as Bakery Yeast Option

2025-06-14

Chinyere Eleanya , Uchechukwu Igboanugo , Nwamaka Anthonia Dibua +4 more | International Journal of Research and Innovation in Applied Science

The ability of yeast rise dough, enhance texture and sensory properties are highly valued by bakers. The aim of this study was to evaluate dough rising capacity of a novel … The ability of yeast rise dough, enhance texture and sensory properties are highly valued by bakers. The aim of this study was to evaluate dough rising capacity of a novel yeast Yarrowia phangngaensis isolated from palmwine as bakery yeast option. Palmwine samples were collected from different parts of Anambra State. Thirty-five yeast isolate were screened for bakery yeast potentials, selected yeasts were subjected to stress tolerance, optimization of cultural conditions, pathogenicity test, dough leavening capacity, sensory evaluation and toxicology study. The results show that the most suitable yeast was Yarrowia phangngaensis. The optimum growth temperature of the test organisms were 280C and 300C for commercial yeast (CY) and Yarrowia phangngaensis (YP) respectively. Optimum growth time and pH was 72h and 5 respectively for both organisms. Stress tolerance test shows that both yeasts grew optimally at 2% salt concentration. The pathogenicity test on the isolate was negative and the dough leavening capacity of the isolate was appreciable. Maximum Dough Rising Capacity (DRC) of 5.69 and 5 was recorded at 150 h for CY and YP respectively. Statistically, CY shows strong positive correlation while YP shows moderate positive correlation between DRC and time. Albino rats used for toxicology study remained normal till the end of the observation period. YP can be utilized for industrial use.

Analysis of Sensory Qualities and Microbial Community Structure in the Fermented Grains by Low-Temperature Daqu from Different Regions of China

2025-06-14

Fanshu Xiang , Wenchao Cai , Qiangchuan Hou +5 more | Current Microbiology

Chemical Characterization of Hot Trub and Residual Yeast: Exploring Beer By-Products for Future Sustainable Agricultural Applications

2025-06-13

Laura Alessandroni , Riccardo Marconi , Marco Zannotti +6 more | Foods

Three types of solid waste are produced during beer fermentation: spent grain, hot trub, and residual yeast. While the first is used as livestock feed, the seconds has not yet … Three types of solid waste are produced during beer fermentation: spent grain, hot trub, and residual yeast. While the first is used as livestock feed, the seconds has not yet found any real reapplication in the field of circular economy. The aim of this work is to study and characterize these two brewing wastes, i.e., hot trub and residual yeast, to evaluate their potential reuse in the agricultural field. Samples from top-fermented and bottom-fermented beers were chemically investigated. Initially, the safety was assessed via multi-detection analysis of 57 mycotoxins, and all samples were deemed safe. Subsequently, the chemical and elemental composition was examined via ICP-MS and microanalysis, along with phenolic compounds and antioxidant activity via HPLC and spectrophotometric determinations, to achieve a thorough characterization of these waste samples. The C/N ratio of residual yeast from top-fermented beer and hot trub of the bottom-fermented one were near the optimal one (10:1). This research marks an initial step towards repurposing brewery waste materials as fertilizers. The subsequent steps will involve the formulation and field trials.

Impact of the Wood Species Used on the Chemical Composition, Color and Sensory Characteristics of Wine

2025-06-13

Ana M. Martínez‐Gil , María del Álamo Sanza , María Asensio-Cuadrado +2 more | Foods

In recent decades, the use of wood pieces has been promoted as a viable alternative to barrels to improve the quality of white wines. However, most available studies have focused … In recent decades, the use of wood pieces has been promoted as a viable alternative to barrels to improve the quality of white wines. However, most available studies have focused on red wines. Given that white and red wines present significant oenological differences that affect their development and final characteristics, it is necessary to expand research specifically to the case of white wines. For this reason, this study evaluates the impact of using pieces of traditional oak wood (Quercus petraea (two origins: French and Romanian) and Quercus alba), other oaks (Quercus humboldtti and Quercus candicans) and other genera (Robinia pseudoacacia, Acacia dealbata, Prunus avium and Nothofagus pumilio) on the quality of white wine during the short period of contact with the wood. The results show that aging with the different woods has little effect on the oenological parameters of the wine; however, it does lead to a change in the phenolic composition and in the final chromatic characteristics of the white wines. From a sensory point of view, the wines showed different sensory profiles depending on the type of wood used. In general, the tasting panel preferred the white wine aged with French Quercus petraea wood pieces, followed by the wine aged with Quercus humboldtti wood pieces and the wine aged with Robinia speudoacacia wood pieces. This research improves our understanding of the potential impact of using pieces of different woods in white wines, describing the potential interest of some that have not been studied before, such as Quercus humboldtti.

Aroma generation of fermented fruit wines: potential enhancement strategies via fermentation and aging process

2025-06-13

Xinman Lou , Jiashu Sun , Haojun Yang +5 more | Critical Reviews in Food Science and Nutrition

Aroma plays a key role in decisions to purchase fruit wines. Fermented fruit wines (FFWs) are produced through endogenous means of microorganisms/enzymes and aging processes without additional additives to produce … Aroma plays a key role in decisions to purchase fruit wines. Fermented fruit wines (FFWs) are produced through endogenous means of microorganisms/enzymes and aging processes without additional additives to produce natural volatile aroma compounds (VOCs). However, most FFWs lack sufficient aroma, and the diversity of raw fruits complicates the effective regulation of flavor. Fermentation and aging processes are critical for the development of aroma profiles, significantly related to the metabolism of aroma precursors and the transformation of VOCs. Fermentation strains and bio-enzymes are regarded as direct driving forces for fermentation aroma generation, accompanied by the release of bound aroma. Consecutively, high efficiency and eco-friendly emerging technologies (e.g. microwave, ultrasonic, and ultra-high-pressure) are replacing traditional long-aging processes, which perfect aroma profiles by releasing cell intracellular matrix, accelerating chemical reactions, improving mass transfer, modifying enzyme activity, and degrading aroma-bound macromolecules. This review systematically outlines recent significant points on aroma generation in FFWs and potential aroma enhancement strategies regulated by key driving factors, namely fruit pretreatment, fermentation parameter optimization, aroma precursor reinforcement, bio-enzyme application, microbial interactions, and emerging aging technologies. It is desired that theoretical basis and technical support for the establishment of flavor-oriented regulation strategies of FFWs can be provided.

Modulation of Biochemical Traits in Cold-Stored ‘Karaerik’ Grapes by Different Edible Coatings

2025-06-12

Nurhan Keski̇n , Sinem Karakuş , Harlene Hatterman‐Valenti +7 more | Horticulturae

Understanding the effects of edible coatings on postharvest quality and shelf life of ‘Karaerik’ grapes is crucial for improving storage outcomes and reducing losses. However, limited information exists regarding the … Understanding the effects of edible coatings on postharvest quality and shelf life of ‘Karaerik’ grapes is crucial for improving storage outcomes and reducing losses. However, limited information exists regarding the effectiveness of different coating materials on this regionally significant variety. In this study, ‘Karaerik’ grapes were treated with carboxymethyl cellulose (CMC) and locust bean gum (KB) coatings and stored under cold conditions (0 ± 0.5 °C, 90–95% relative humidity) for 0, 25, 45, and 60 days. Storage duration and coating treatments significantly affected most physical, physiological, and biochemical parameters. During storage, grape weight loss progressively increased, reaching 9.60% in the control by day 60. Coatings slightly reduced this loss, with KB showing the lowest (5.11%) compared to the control (5.69%). Respiration initially declined but surged again at day 60, especially in the control (96.4 μmol CO2/kg·hour), while coatings helped mitigate this rise. Ethylene release remained unchanged. A slight pH decline (~4.6%) was observed in the control, while KB-treated grapes maintained higher pH and lower acidity. Soluble solids remained stable across treatments. Color changed notably during storage: a* nearly doubled (more redness), b* increased (less blue), and chroma (C*) declined by ~25%, especially in uncoated grapes. Total sugar dropped by ~43% in KB-treated grapes, with the control retaining the most. Tartaric acid decreased by ~55%, notably in KB samples. Antioxidant activity and total phenolics declined significantly (~66%) in the control. CMC coating better-preserved antioxidant capacity, while the control showed the highest phenolic levels overall. Ferulic, gallic, and chlorogenic acids increased toward the end of storage, particularly in coated grapes. In contrast, rutin and vanillic acid peaked mid-storage and were better preserved in the control. The heatmap showed significant metabolite changes in fruit samples across 0D, 25D, 45D, and 60D storage periods under CMC, CNT, and KB treatments, with distinct clustering patterns revealing treatment-specific biochemical responses. The correlation matrix revealed strong positive relationships (r > 0.70) between total sugar, glucose, and fructose levels, while ethylene showed significant negative correlations (−0.65 to −0.85) with maturity index, pH, and total soluble solids, indicating interconnected metabolic pathways during fruit ripening and storage. We conclude that edible coating selection significantly influences grape biochemical stability during cold storage, with CMC emerging as a superior choice for maintaining certain quality parameters.

Monitoring viable yeast populations using flow cytometry in spontaneous and inoculated alcoholic fermentations of white must and red mash

2025-06-09

Mateja Potisek , Franc Čuš | European Food Research and Technology