Fruity Character Research Articles

Improving aromatic higher alcohol acetates in wines by co-fermentation of Pichia kluyveri and Saccharomyces cerevisiae: growth interaction and amino acid competition.

Higher alcohol acetates (HAAs) are potent aroma-active esters that impart desirable fruity and floral aromas. However, the conversion of higher alcohol precursors into HAAs is extremely low in winemaking. To investigate the underlying yeast-yeast interaction on targeted improvement of aromatic HAAs, we evaluated fermentation activity, cell viability, amino acid consumption and HAA production when Pichia kluyveri and Saccharomyces cerevisiae were inoculated concurrently or sequentially. Pichia kluyveri PK-21 possessed the ability to survive and increased HAA level up to 5.2-fold in mixed fermentation. Such an increment may benefit from the efficient conversion of higher alcohol precursors into HAAs (>27-fold higher than S. cerevisiae). During mixed fermentation, the two yeasts exhibited crucial interactions regarding cell growth and amino acid competition. Saccharomyces cerevisiae dominated over the co-inoculated P. kluyveri by efficient uptake of amino acids and biomass production. However, this dominance decreased in sequential fermentation, where P. kluyveri growth increased due to the consumption of preferred amino acids prior to S. cerevisiae. Pearson correlation analysis indicated that phenylalanine and aspartic acid may act as positive amino acids in boosting P. kluyveri growth and HAA production. Laboratory-scale winemaking validated the fermentation performance of P. kluyveri in sequential inoculum, resulting in a balanced aroma profile with enhanced floral and tropical fruity characteristics in the final wines. This study proposes a microbial, non-genetically engineered approach for targeted increase of HAA production in winemaking and the findings provide new insights into yeast-yeast interactions. © 2024 Society of Chemical Industry.

Decoding the Effect of Running on Flavor Perception Changes during Consumption of Sports Drinks.

An online survey was conducted to show that most respondents preferred sports drinks with sweet and fruity characteristics. Eleven sports drinks with higher consumers' preferences were further selected for aroma and taste evaluation. Temporal dominance of sensations analysis showed that fruity and fresh attributes were dominant, while sour and fruity sweet were dominant tastes during consumption. β-Damascenone, β-ionone, and linalool contributing to floral perception, γ-decalactone, ethyl cinnamate, and isoamyl acetate contributing to fruity perception, and menthol contributing to fresh perception were confirmed by odor activity value analysis. Running affected the nasal air flow and the saliva secretion, resulting in the flavor perception changing from fruity sweet, sweet, and fruity to sour because the recognition threshold decreased for sweet, fruity, floral, and fresh flavors and increased for saltiness, astringency, and sour tastes.

Influence of oak wood on the chemical and organoleptic profile of white wines

The use of oak wood in various forms for the production of white wines has become an increasingly popular practice among winemakers. As a result of extraction, condensation and other processes, their chemical composition and sensory profile were modified. Phenolic compounds and volatile aromatic substances passed from the wood to the wine improving the aroma and taste and enhancing its antioxidant activity. Their quantity has depended on the botanical type and origin of the wood and the method of its heat treatment. In the production of white wines several technologies have been applied - conducting the alcoholic fermentation and aging on lees in barrels, completing the fermentation in tanks and racking the wine to the barrels, starting the fermentation in tanks but in the middle of the process racking the fermenting juice to the barrels. Into the wine, of phenols mainly passed gallotannins and ellagitannins and of aromatic substances – eugenol, isoeugenol, vanillin, furan derivatives, lactones, etc. Further to the use of barrels, the application of alternative oak forms has become more and more popular, which in the case of white wines allowed avoiding the volatile components oxidation. The result was a quality product with better technological properties. The wines acquired hints of wood without losing their freshness and fruity character.

Effect of Maturation with American Oak Chips on the Volatile and Sensory Profile of a Cabernet Sauvignon Rosé Wine and Its Comparison with Commercial Wines

Rosé wines are commonly consumed as young wines mainly due to their freshness and fruity character. Nevertheless, in recent years a new market looking for alternatives to traditional wines has emerged. Considering this, the study of the volatile and sensory profiles of a varietal rosé wine aged with oak chips was carried out. Two Cabernet Sauvignon rosé wines were made: one was maturated with oak chips and the other without. Both wines were physicochemically characterized. Then, their volatile and sensory profiles were analyzed, also including two commercial wines. The results showed that the produced wines complied with Mexican regulations. Also, they showed greater relative areas in compounds such as ethyl (E)-2-hexenoate, ethyl heptanoate, ethyl nonanoate, ethyl 3-nonenoate, β-citronellol, (±)-trans-nerolidol, and β-damascenone. In their sensory profile, they were mostly related to attributes such as berries, prune, bell pepper, and herbaceous notes. Among the compounds related to barrel maturation, only cis-oak-lactone was identified in the rosé wine matured with chips. However, it was associated with vanilla, woody, smoky, and spicy attributes. According to the results, the maturation of rosé wines with oak chips could be a good alternative to provide them with unusual notes and thus offer new alternatives to traditional and new wine consumers.

Metabolomics analysis reveals the patterns and mechanisms of volatile metabolite in oolong tea during storage

Oolong tea is famous for its rich floral and fruity aroma which further develops into a distinct aged aroma over time. Storage plays an important role in the quality of the aroma. However, the precise aroma characteristics and profile components of long-term stored oolong tea have not been fully elucidated. In this study, we adopted gas chromatography-mass spectrometry (GC-MS) in combination with multivariate statistical analysis to investigate the dynamic changes in volatile metabolites of oolong tea during different storage periods. Our findings revealed 14 aroma components that served as markers distinguishing aged oolong tea from new tea. With storage years increased, the characteristic woody aroma components of (6,6-dimethyl-2-bicyclo[3.1.1]hept-2-enyl)methanol, 3,5,5-trimethylcyclohex-2-en-1-one gradually increased. Additionally, specific floral and fruity aroma components, such as 2-(4-methylcyclohex-3-en-1-yl)propan-2-yl acetate, 2-[(1S)-4-methylcyclohex-3-en-1-yl]propan-2-ol, ethyl 3-(furan-2-yl)propanoate were also found to be accumulated year by year, contributing to the woody, floral, and fruity character observed in aged tea. 5-Methyl-6,7-dihydro-5H-cyclopentapyrazine decreased regularly during storage. KEGG enrichment analysis demonstrated that the significant enrichment pathways of differential volatile metabolites were primarily related to metabolic pathways and the biosynthesis of secondary metabolites. This study provided a comprehensive understanding of the changes in volatile metabolites and aroma quality of oolong tea during storage, thereby providing guidance for the optimal storage conditions of oolong tea.

오디 탄산음료 제조를 위한 최적 품종 선발 및 제조된 탄산음료의 품질평가

Background: The study aimed to identify the optimal variety of mulberry for soft drinks production.BRMethods and Results: Fruity characteristics, minerals, and functional composition [total flavonoid, total anthocyanin, and 1-deoxynojirimycin (1-DNJ)] of 11 different mulberry varieties were investigated and compared. The ‘Iksu’ variety was optimal for soft drink production. Mulberry extracts and concentrated fruit were carbonated before evaluating different properties, including physicochemical (total soluble solid (TSS), titrable acidity, °Brix : Acid ratio, and total sugar) and sensory characteristics (color, flavor, taste, mouth feel, and overall acceptability) using different mulberry extract concentration in combination with various levels of additional sugar. Optimum physiochemical parameters were obtained with mulberry extract concentration level of 0.1112% with 12 °Brix (mulberry base formulation T7). Based on the hedonic sacale, the sensory evaluation identified the optimum combination of mulberry extract concentrates with the additonal sugar level. T7 contained superior sensory qualities. The T7 mulberry base carbonated at 120 psi pressure had the highest for sensory quality than those at 75 or 120 psi.BRConclusions: Ssoft drinks developed using the Iksu mulberry variety with the base formulation T7 were optimal for all physicochemical characteristics. This formula generally produced impressive sensory characteristics, providing a promising alternative to synthetic soft drinks.

Influence of Different Pre-Distillation Steps on Aromatic Profile of Plum Spirits Produced by Traditional and Modified Methods

The aim of this study was to compare the aromatic profile of plum spirits, obtained from the Požegača and Stanley varieties, as affected by different combinations of pre-distillation steps used in traditional and six modified production methods that are common in Serbian distilleries. Traditional plum spirits (produced from spontaneously fermented mashes of crushed plums with stones distilled after two months of storage) had the highest contents of ethyl acetate, benzaldehyde, and total acids, which resulted in the occurrence of an unpleasant solvent-like and stone-like odour and acidic taste. These sensory defects were overcome by the distillation of fermented mashes immediately after the completion of alcoholic fermentation. Depending on the combination of the pre-distillation steps, plum spirits from mashes distilled immediately after alcoholic fermentation were characterized by different aromatic profiles: closer to traditional (from spontaneously fermented crushed plums with/without stones) or with a more pronounced fruity character (from pulped plums without stones regardless of the way of fermentation). These differences in aroma profiles have arisen mostly because of the significantly different contents and OAVs of ethyl esters and volatile fatty acids. The appropriate combination of the pre-distillation steps, which is adapted to the variety, can significantly improve the quality of the plum spirit compared to the traditionally produced spirit.

Application of non-Saccharomyces yeasts with high β-glucosidase activity to enhance terpene-related floral flavor in craft beer

The rising interest in craft beer urging for novel yeasts that provide diverse attributes. This research aimed to explore the potential of four non-Saccharomyces yeasts with high β-glucosidase activity in beer fermentation. Fermentation ability, adverse environment resistance and carbohydrate affinity were measured via growth and physiochemical parameters and, based on these results, a Candida glabrata (D18) yeast was selected for subsequent sequential fermentations. Aroma analysis of the fermented beer was then performed using gas chromatography-mass spectrometry, demonstrated that some glucoside-binding terpenes had been significantly increased. In two D18 involved groups, geraniol content increased 51.5/11-fold in the single and mixed fermentations, respectively, while linalool increased 1.36-fold in the mixed fermentation, providing the final beer product with unique floral and fruity characteristics. Principal component analysis and sensory evaluation were also applied to further demonstrate these distinctions. Overall, D18 was found to be a potential yeast for beer fermentation with unique properties.

Non-Targeted Metabolomics Analysis Revealed the Characteristic Non-Volatile and Volatile Metabolites in the Rougui Wuyi Rock Tea (Camellia sinensis) from Different Culturing Regions.

Rougui Wuyi Rock tea (WRT) with special flavor can be affected by multiple factors that are closely related to the culturing regions of tea plants. The present research adopted non-targeted metabolomics based on liquid chromatography–mass spectrometry (LC-MS) and gas chromatography–mass spectrometry (GC-MS), aroma activity value method (OAV), and chemometrics to analyze the characteristic metabolites of three Rougui WRTs from different culturing regions. The results of sensory evaluation showed that the three Rougui Wuyi Rock teas had significantly different flavor qualities, especially in taste and aroma. Rougui (RG) had a heavy and mellow taste, while cinnamon-like odor Rougui (GPRG) and floral and fruity odor Rougui (HGRG) had a thick, sweet, and fresh taste. The cinnamon-like odor was more obvious and persistent in GPRG than in RG and HGRG. HGRG had floral and fruity characteristics such as clean and lasting, gentle, and heavy, which was more obvious than in RG and GPRG. The results of principal component analysis (PCA) showed that there were significant metabolic differences among the three Rougui WRTs. According to the projection value of variable importance (VIP) of the partial least squares discriminant analysis (PLS–DA), 24 differential non-volatile metabolites were identified. The PLSR analysis results showed that rutin, silibinin, arginine, lysine, dihydrocapsaicin, etc. may be the characteristic non-volatiles that form the different taste outlines of Rougui WRT. A total of 90 volatiles, including aldehydes, alcohols, esters, and hydrocarbons, were identified from the three flavors of Rougui WRT by using GC-MS. Based on OAV values and PLS-DA analysis, a total of 16 characteristic volatiles were identified. The PLSR analysis results showed that 1-penten-3-ol, α-pinene, 2-carene, β-Pinene, dehydrolinalool, adipaldehyde, D-limonene, saffron aldehyde, and 6-methyl-5-hepten-2-one may be the characteristic volatiles that form the different aroma profile of Rougui WRT. These results provide the theoretical basis for understanding the characteristic metabolites that contribute to the distinctive flavors of Rougui WRT.

Effects of secondary fermentation of four in-bottle Saccharomyces cerevisiae strains on sparkling cider sensory quality

In this study, the first fermentation of Fuji apple juice was carried out using Saccharomyces cerevisiae WLS21 and continued a second fermentation using S. cerevisiae HYJ1, HYJ2, PE2, and Y41 in sealed bottles after adjusting the sugar level. The physicochemical indexes, aromas, and sensory characteristics of four sparkling ciders were analyzed. The results revealed that HYJ2 produced the highest amount of ethanol and Y41 had the highest pressure in the bottle at the end of fermentation. Y41 produced the highest citric and succinic acids and HYJ1 produced higher fumaric acid and total volatiles. HYJ1 cider had an obvious herbaceous odor, and Y41 cider had a fruity character. Sixty-seven volatiles were detected from four sparkling ciders (55 fermentative and 12 non-fermentative aromas). Esters (EEFAs and HAAs) were the main volatile aroma family produced during secondary fermentation, and terpenes contributed the most to fruity odor. Based on univariate (ANOVA) and multivariate analysis of variance (PLS-DA) screening of four cider significant variables, 13 volatiles with variable predictive importance (VIP)≥1 were identified. PLSR analysis revealed that 2-methylbutyl acetate, ethyl heptanoate, 2-methyl-1-butanol, nonanal, 2-nonanone, β-damascenone, and linalool were potential volatile markers for OAV>1.

Effects of the proteins of indica rice and indica waxy rice on the formation of volatiles of sweet rice wine

SummaryThe proteins in the raw materials affect the formation of flavour during fermentation. Among all the fermentation broth of protein fraction in the study, the rice prolamin and albumin effectively promoted floral, honey and fruity characteristics in fermentation with higher level of β‐phenylethyl alcohol, 2,4‐dimethyl‐benzaldehyde and ethyl hexadecanoate than those in the fermentation of globulin and glutelin; albumin is with higher level of higher alcohols, but higher alcohols are not good for health because of their acute toxicity and neurotoxic effects. In a further fermentation experiment of addition of prolamin, extra prolamin significantly promoted the formation of aroma volatiles, especially medium and long fatty acid esters and β‐phenylethyl alcohol and its acetate, and the content of β‐phenethyl acetate in sweet rice wine with added prolamin was more than twice that of single sweet rice wine. This study demonstrates that the different rice protein components significantly affect the volatiles generated by microorganism metabolism to impact the flavour of sweet rice wine, and the flavour quality of sweet rice wine can be enhanced by increasing the prolamin content.

Isolation and characterisation of autochthonousSaccharomyces cerevisiaefrom ‘Pago’ Merlot wines of Utiel‐Requena (Spain) origin

Background and Aims To achieve both the control of the undesirable yeasts and the improvement of the characteristics of Merlot ‘Pago’ wines, Saccharomyces cerevisiae yeast diversity was investigated in a spontaneous ‘Pago’ Merlot fermentation from the Utiel-Requena region (Spain). Isolates of S. cerevisiae were characterised by a holistic procedure using the same Merlot grape must from which they were isolated. Methods and Results Yeasts were identified by internal transcribed spacer analysis and typed by HinfI mDNA restriction analysis. Growth and metabolic characteristics of the isolates were determined by laboratory-scale (50 L) fermentations of Merlot must and the composition of the polyphenolic and the volatile compounds and the sensory attributes of the wines were determined. Twelve S. cerevisiae strains were isolated and characterised. Strains 2E, 4A, 7A and 7F had better growth characteristics. Strains 9C and 7F produced wines of good intensity and colour quality, marked intensity and aroma quality, fruity character and better overall quality. Strain 9C displayed poor growth. Conclusions Strain 7F combined good growth characteristics and produced Merlot wines with the best colour, aroma and flavour characteristics during microvinifications. Significance of the Study Characterisation of S. cerevisiae made entirely in Merlot grape must allowed the influence of yeast strains on the final characteristics of commercial-scale Merlot ‘Pago’ wines to be more accurately deduced.

The Impact of the Fermentation Strategy on the Flavour Formation of Ilzer Rose (Malus domestica Borkh.) Apple Wine.

The flavour and the volatilome of apple wines made from the Austrian heritage variety Ilzer Rose was in the scope of this study. The apple wines were produced by adopting oenological practises that are not commonly used in fruit wine production. Different fermentation strategies including the addition of enzymes with β-glucosidase activity, addition of a fining agent, maceration of the mash along with mash fermentation were applied. The volatile compounds of the juices as intermediates and the resulting apple wines were analysed using headspace-SPME GC-MS. CATA technique with a well-trained panel was applied for sensory evaluation. The results show that the flavour of single-variety apple wine can be significantly altered by taking oenological measures. High correlations were found between the results of the analytical investigation and the sensory evaluation. Maceration of the mash leads to an increase in the fruity character of the products, also reflected by significantly higher fruit ester quantities in the wine. During mash fermentation, spontaneous malolactic fermentation was induced leading to a product with new, but thoroughly interesting sensory properties of the apple wine. The results of this study demonstrate that the integration of oenological measures may open a wide field to the development of a high diversity in apple wine flavour.

Advances in Wine Fermentation

Fermentation is a well-known natural process that has been used by humanity for thousands of years, with the fundamental purpose of making alcoholic beverages such as wine, and also other non-alcoholic products. From a strictly biochemical point of view, fermentation is a process of central metabolism in which an organism converts a carbohydrate, such as starch or sugar, into an alcohol or an acid. The fermentation process turns grape juice (must) into wine. This is a complex chemical reaction whereby the yeast interacts with the sugars (glucose and fructose) in the must to create ethanol and carbon dioxide. Fermentation processes to produce wines are traditionally carried out with Saccharomyces cerevisiae strains, the most common and commercially available yeast, and some lactic acid bacteria. They are well-known for their fermentative behavior and technological characteristics, which allow obtaining products of uniform and standard quality. However, fermentation is influenced by other factors as well. The initial sugar content of the must and the fermentation temperature are also crucial to preserve volatile aromatics in the wine and retain fruity characters. Finally, once fermentation is completed, and most of the yeast dies, wine evolution continues until the production of the final product.

Wood powders of different botanical origin as an alternative to barrel aging for red wine

Wood powders are produced in large quantity as by-product of barrel, staves and chips industry. Differently from larger particles (chips), the use of wood powders in winemaking is not admitted (Regulation (CE) n. 934/2019); however, it could represent a cheap and sustainable alternative for the accelerated aging of red wine. To evaluate their potential use in winemaking, a comparative study on the use of wood powders from oak, chestnut and acacia wood for the accelerated aging of red wine (cv. Aglianico) was conducted. This alternative aging was compared to the aging in wood barrels from the same botanical species. The wine aged in contact with powders underwent a quicker evolution of polyphenolic fraction. After 15 days of contact, the loss of total anthocyanins was higher than that observed after 6 months of aging in barrels (from 4 to 14% with respect to the corresponding kind of barrel). The amount of polymeric pigments tannins–anthocyanins–tannins in wines aged in contact with powders was higher respect to the wines aged in barrels (from 7 to 21% with respect to the corresponding kind of barrel), while the greatest loss of total tannins was detected in the oak barrels (28% less with respect to the control). There were several differences in wine phenolic acids due to wood botanical origin, with the clearest differences being between oak and the alternative wood species (chestnut and acacia). Also, there was a significant botanical effect on sensory profiles. Indeed, both among barrels and among powders, oak wood was the one that gave the strongest wood odor character. However, all the treatments with wood powders (oak, acacia and chestnut) preserved the fruity character of wine, conferring in the meanwhile non-dominant woody notes.

Molecular characterization of the Saccharomycopsis fibuligera ATF genes, encoding alcohol acetyltransferase for volatile acetate ester formation.

Aroma ester components produced by fermenting yeast cells via alcohol acetyltransferase (AATase)-catalyzed intracellular reactions are responsible for the fruity character of fermented alcoholic beverages, such as beer and wine. Acetate esters are reportedly produced at relatively high concentrations by non-Saccharomyces species. Here, we identified 12 ATF orthologues (SfATFs) encoding putative AATases, in the diploid genome of Saccharomycopsis fibuligera KJJ81, an isolate from wheat-based Nuruk in Korea. The identified SfATF proteins (SfAtfp) display low sequence identities with S. cerevisiae Atf1p (between 13.3 and 27.0%). All SfAtfp identified, except SfAtf(A)4p and SfAtf(B)4p, contained the activation domain (HXXXD) conserved in other Atf proteins. Culture supernatant analysis using headspace gas chromatography mass spectrometry confirmed that the recombinant S. cerevisiae strains expressing SfAtf(A)2p, SfAtf(B)2p, and SfAtf(B)6p produced high levels of isoamyl and phenethyl acetates. The volatile aroma profiles generated by the SfAtf proteins were distinctive from that of S. cerevisiae Atf1p, implying difference in the substrate preference. Cellular localization analysis using GFP fusion revealed the localization of SfAtf proteins proximal to the lipid particles, consistent with the presence of amphipathic helices at their N- and C-termini. This is the first report that systematically characterizes the S. fibuligera ATF genes encoding functional AATases responsible for acetate ester formation using higher alcohols as substrate, demonstrating their biotechnological potential for volatile ester production.

Hayıt (Vitex agnus-castus L.) Ballarının Uçucu Bileşenlerinin ve Duyusal Özelliklerinin Tanımlanması

Bu çalışmada Aydın, Çanakkale, İzmir ve Muğla illerinde üretilen hayıt ballarının bazı fiziksel ve kimyasal özellikleri ile uçucu bileşenlerinin ve duyusal özelliklerinin tanımlanması amaçlanmıştır. Değerlendirilen hayıt ballarında toplam 16 farklı uçucu bileşen belirlenmiştir (4 aldehit, 3 furan, 2 alkol, 2 sülfürlü bileşik, 2 terpen, 1 alkan, 1 benzenik bileşik ve 1 keton). Hayıt ballarının ortak uçucu bileşenlerinin dimetil sülfit, oktan, nonanal, 2-furankarboksaldehit, 2-etil-1-hegzanol, 1-(2-furanil)-etanon, benzaldehit, 5-metil-2-furankarboksaldehit ve benzenasetaldehit olduğu belirlenmiştir. Bütün hayıt ballarında benzenasetaldehit en fazla bulunan uçucu bileşen olup ardından benzaldehit ve 2-furankarboksaldehit gelmektedir. Duyusal değerlendirme sonucunda hayıt ballarında çiçeğimsi, meyvemsi, karamelimsi, acı badem, fermente, hayvanımsı, baharatımsı, vaksımsı ve odunumsu koku karakteri, tatlı ve ekşi tat karakterleri ile burukluk ağız hissi algılanmıştır. Bütün örneklerde çiçeğimsi, meyvemsi, karamelimsi, tatlı ve ekşi karakter yoğun olarak algılanmıştır.

Identification and analysis of odor-active compounds from Choerospondias axillaris (Roxb.) Burtt et Hill with different moisture content levels and lacquer treatments

The problem of indoor odors can greatly affect a room’s occupants. To identify odorants and comprehensively evaluate emissions from wooden materials, emissions and odors from Choerospondias axillaris (Roxb.) Burtt et Hill with different moisture content percentages and lacquer treatments were investigated in this study. Thermal desorption–gas chromatography–mass spectroscopy/olfactometry was used to analyze the release characteristics. In total, 11 key odor-active compounds were identified as moisture content gradually decreased, concentrating between 15 and 33 min. Total volatile organic compounds, total very volatile organic compounds, and total odor intensity decreased as moisture content decreased. In addition, 35 odor-active compounds, including aromatics, alkenes, aldehydes, esters, and alcohols, were identified in the odor control list. Polyurethane (PU), ultraviolet (UV), and waterborne coatings had a good inhibitory effect on eight odor characteristics, but some scents arose after lacquer treatment. For equilibrium moisture content, the major characteristics of Choerospondias axillaris were fragrant (9.4) and mint-like (3.0) compared with the fragrant (8.2), fruity (7.8), and pleasant (5.8) characteristics of PU coating; the flowery (5.9), fragrant (5.0), glue-like (4.3), and pineapple-like (4.3) characteristics of UV coating; and the antiseptic solution (3.6), fragrant (2.9), cigarette-like (2.8), and fruity (2.5) characteristics of waterborne coating. Based on multicomponent evaluation, a Choerospondias axillaris board with waterborne coating was suggested for use indoors.

Chitosan in Sparkling Wines Produced by the Traditional Method: Influence of Its Presence during the Secondary Fermentation.

Chitosan is a polysaccharide admitted in winemaking as clarifying, antimicrobial and chelating agent. In addition, evidence about its antioxidant and radical scavenging activities have been recently reported in wine conditions. As an insoluble adjuvant, chitosan efficacy also depends on the duration of its contact with the matrix. In the case of sparkling wines obtained following the traditional method, for instance, the addition of chitosan before the secondary fermentation would permit a prolonged contact of the polymer with wine and yeast lees. However, information on the effects of this practice on final products is totally unknown. In this work, the addition of chitosan during the secondary fermentation of a traditional sparkling wine production method has been investigated for its effects on both the physicochemical and sensory characteristics of the resulting wine. After 12 months of “sur lie” maturation, chitosan was found to increase the protein and amino acid content of wines up to about 50% and 9%, respectively, with limited change of phenolics and organic acids. Volatile compounds, particularly esters, were increased as well, which was reflected by higher values for fruity character and aroma intensity after sensory tests. Foaming features, evaluated by sensory and physical measurements, were also positively affected.

Oral persistence of esters is affected by wine matrix composition

The present work evaluated for the first time the influence of wine matrix composition on oral ester persistence. To do that, the in mouth behaviour (oral retention and persistence) of six esters was followed in nine individuals after they rinsed their mouths with four rosé wines presenting two levels (low and moderate) of ethanol (0.5% or 10% v/v) and polyphenols (402 ± 10 or 661 ± 33 mg gallic acid/L). Overall, polyphenols and specially, ethanol, affected the oral retention of esters and their subsequent oral persistence, in an individual, compound and concentration dependent manner. The wine with moderate ethanol and low polyphenol content and the wine with low ethanol and moderate polyphenol content presented an increased oral ester persistence respect to the control wine (low ethanol/polyphenol content). However, the wine with moderate ethanol/polyphenol content showed most likely a lower oral ester persistence compared to the rest of the wines. Thus, an interaction between ethanol and polyphenols at specific concentrations could reduce oral ester persistence, and likely the fruity character of wines. The information generated in this research can be used by winemakers to understand how different winemaking techniques, which might alter wine ethanol and polyphenol content, may also affect wine aroma quality.