1,721,008 research outputs found
Metschnikowia pulcherrima selected strain for ethanol reduction in wine: Influence of cell immobilization and aeration condition
Full text linkOne of the most important problems in the winemaking field is the increase of ethanol content in wine. Wines with high ethanol level negatively affect wine flavor and human health. In this study, we evaluated the use of a selected strain of Metschnikowia pulcherrima in immobilized form and under different aeration conditions, to reduce the ethanol content evaluating the volatile profile of the resulting wines. In a preliminary screening the best conditions regarding free/immobilized cells, static/aerated fermentation and inoculation level were identified. Bench-Top fermentation trials with different aeration conditions showed that the use of M. pulcherrima selected strain with aeration flow of 20 mL/L/min during the first 72 h of fermentation, led an ethanol reduction of 1.38% (v/v) in comparison with Saccharomyces cerevisiae control strain. The analytical profile of the resulting wines did not show any negative feature. Indeed, the concentration of ethyl acetate, that above its sensory threshold impacts negatively the wine sensory profile, was found at an acceptable level. On the other hand, an increase in the concentration of significant fruity and flower compounds was found
Effectiveness against strawberry postharvest decay of volatile organic compounds produced by biocontrol agents.
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Volatile profile of reduced alcohol wines fermented with selected non-Saccharomyces yeasts under different aeration conditions
No full textOver the last decades there has been an increase in ethanol concentration in wine. High ethanol concentration
may impact negatively wine flavor and can be associated with harmful effects on human health. In this study, we
investigated a microbiological approach to reduce wine ethanol concentration, using three non-Saccharomyces
yeast strains (Metschnikowia pulcherrima, Torulaspora delbrueckii and Zygosaccharomyces bailii) in sequential
fermentations with S. cerevisiae under different aeration conditions. At the same time, we evaluated the volatile
profile of the resulting reduced alcohol Chardonnay wines. Results showed that the non-Saccharomyces yeasts
tested were able to reduce wine ethanol concentration when oxygen was provided. Compared to S. cerevisiae
wines, ethanol reduction was 1.6% v/v, 0.9% v/v and 1.0% v/v for M. pulcherrima, T. delbrueckii and Z. bailii
sequential fermentations, respectively. Under the conditions evaluated here, aeration did not affect acetic acid
production for any of the non-Saccharomyces strains tested. Although aeration affected wine volatile profiles, this
was depended on yeast strain. Thus, wines produced with M. pulcherrima under aeration of 0.05 volume of air
per volume of culture per minute (VVM) showed excessive ethyl acetate content, while Z. bailli wines produced
with 0.05 VVM aeration had increased concentrations of higher alcohols and volatile acids. Increased concentrations
of these compounds over their sensory thresholds, are likely to impact negatively on wine sensory
profile. Contrarily, all three non-Saccharomyces strains under 0.025 VVM aeration conditions produced wines
with reduced ethanol concentration and acceptable chemical volatile profiles
Volatile organic compounds from Wickerhamomyces anomalus, Metschnikowia pulcherrima and Saccharomyces cerevisiae inhibit growth of decay causing fungi and control postharvest diseases of strawberries
Full text linkAssessment of non-conventional yeasts with potential probiotic for protein-fortified craft beer production
Full text linkThe use of non-conventional yeasts could be an interesting source of biodiversity for developing innovative fermented beverages. Here, 43 wild yeast strains belonging to different genera such as Lachancea, Kluyveromyces, Torulaspora, Metschnikowia, Kazachstania, Brettanomyces, Pichia, Candida, Hanseniaspora, Rhodotorula, Rodosporidobolus and Saccharomyces, previously evaluated for their probiotic traits, have been tested for craft beer production. Different experimental lines were carried out to develop a new beverage which could combine increased aromatic characteristics and improved nutritional properties: i) beers produced from pils wort (PW); ii) beers from pils wort enriched with lentil (PLW) or chickpea flour extracts (PCW). PW beer trials were characterized by a low ethanol content. The PCW results in beer with an unpleasant aromatic taste, while the presence of lentil (PLW) confers effective fermentative characters and pleasant aromatic notes to the final beers. The selected strains Lachancea thermotolerans, Kazachstania unispora and Saccharomyces cerevisiae determined a significantly increase in the main aromatic compounds such as ethyl acetate, isoamyl acetate and higher alcohols in PLW. The sensorial profile indicated that the beers were characterized with emphasized aromatic attributes. The yeasts selected here, could contribute to obtain a premium craft beer, with highly nutritional and functional characteristics, with a distinctive aromatic character
Starmerella bombicola and saccharomyces cerevisiae in wine sequential fermentation in aeration condition: Evaluation of ethanol reduction and analytical profile
Full text linkIn the last few decades, the increase of ethanol in wine, due to global climate change and consumers’ choice is one of the main concerns in winemaking. One of the most promising approaches in reducing the ethanol content in wine is the use of non-Saccharomyces yeasts in co-fermentation or sequential fermentation with Saccharomyces cerevisiae. In this work, we evaluate the use of Starmerella bombicola and S. cerevisiae in sequential fermentation under aeration condition with the aim of reducing the ethanol content with valuable analytical profile. After a preliminary screening in synthetic grape juice, bench-top fermentation trials were conducted in natural grape juice by evaluating the aeration condition (20 mL/L/min during the first 72 h) on ethanol reduction and on the analytical profile of wines. The results showed that S. bombicola/S. cerevisiae sequential fermentation under aeration condition determined an ethanol reduction of 1.46% (v/v) compared with S. cerevisiae pure fermentation. Aeration condition did not negatively affect the analytical profile of sequential fermentation S. bombicola/S. cerevisiae particularly an overproduction of volatile acidity and ethyl acetate. On the other hand, these conditions strongly improved the production of glycerol and succinic acid that positively affect the structure and body of wine
Purification and characterization of WA18, a new mycocin produced by wickerhamomyces anomalus active in wine against brettanomyces bruxellensis spoilage yeasts
Full text linkWickerhamomyces anomalus strain 18, isolated from a natural underground cheese ripening pit, secretes a mycocin named WA18 that inhibits wine spoilage yeasts belonging to Brettanomyces bruxellensis species, with a broad-spectrum of activity. WA18 was purified, and the purified protein was digested with specific restriction enzymes (lysine K and arginine R cut sites). The LC–MS and LC–MS/MS analysis after enzymatic digestions revealed a molecular weight of 31 kDa. Bioinformatics processing and database research of digested pure killer protein showed 99% identity with a UDP-glycosyltransferase protein. Competitive inhibition assay of killer activity by cell-wall polysaccharides suggests that branched glucans represent the first receptor site of the toxin on the envelope of the sensitive target. The WA18 partially purified crude extract (PPCE) showed high stability of antimicrobial activity at the physicochemical conditions suitable for the winemaking process. Indeed, in wine WA18 was able to counteract B. bruxellensis and control the production of ethyl phenols. In addition, the strain WA18 was compatible with Saccharomyces cerevisiae in co-culture conditions with a potential application together with commercial starter cultures. These data suggest that WA18 mycocin is a promising biocontrol agent against spoilage yeasts in winemaking, particularly during wine storage
Controlled mixed culture fermentation: a new perspective on the use of non-Saccharomyces yeasts in winemaking
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