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Metabolites May 2024Wild yeast suitable for kiwifruit wine fermentation was isolated and purified, and the fermentation process was optimized to increase the alcohol content of the...
Wild yeast suitable for kiwifruit wine fermentation was isolated and purified, and the fermentation process was optimized to increase the alcohol content of the kiwifruit wine. was isolated from kiwifruit pulp by lineation separating, screened by morphological characteristics in Wallerstein Laboratory Nutrient Agar (WL) medium and microscope observation, and further identified by 26S rDNA D1/D2 domain sequence analysis. Taking alcohol content and sensory evaluation as two indexes, the fermentation condition for kiwifruit wine was optimized by single factor and response surface experiment. The optimal fermentation conditions were optimized as follows: the fermentation temperature was at 24 °C, the initial pH was 3.8, the sugar dosage in second step was 8% (/), and the inoculating quantity of and was 0.15 g/L at equal proportion. Under these optimal conditions, the maximum estimated alcohol content was 15.6 vol%, and the kiwifruit wine was light green in color with strong kiwifruit aroma and mellow taste.
PubMed: 38921445
DOI: 10.3390/metabo14060310 -
Journal of the Science of Food and... Aug 2021Fermented cocoa beans (Theobroma cacao L.) are a pivotal raw material for chocolate production. A cocktail yeast applied in the cocoa fermentation process can promote...
BACKGROUND
Fermented cocoa beans (Theobroma cacao L.) are a pivotal raw material for chocolate production. A cocktail yeast applied in the cocoa fermentation process can promote the formation of pleasant metabolites. Saccharomyces, Pichia and Hanseniaspora have been widely used in fermentation to improve the final product organoleptic profile, highlighting that fermentation is a critical point for chocolate flavour precursor production. This study aims to evaluate the impact of Pichia kluyveri and Saccharomyces cerevisiae strains as starter cultures on the fermentation for two cocoa hybrids, FA13 and CEPEC2002.
RESULTS
During fermentation processes, volatile organic compounds (VOCs) and protein profiles were assessed. Chocolates produced were also assessed regarding the presence of VOCs. Eighty VOCs were identified using gas chromatography coupled to mass spectrometry analysis. Mass spectrometry provided the protein profile evolution during fermentation and showed that the profiles changed with inoculation type (spontaneous versus inoculated fermentation). Chocolate obtained from FA13 inoculated with S. cerevisiae strain contained a greater amount of organics acids, being categorised as sourer than chocolate produced by spontaneous fermentation of FA13. CEPEC2002 inoculated with S. cerevisiae strain in co-culture with P. kluyveri strain generated less sour and sweeter chocolate than spontaneous fermentation only.
CONCLUSIONS
Chocolates from inoculated assays with starter cultures were more accepted by evaluators, highlighting that P. kluyveri and S. cerevisiae influence the composition of VOCs. Besides, protein profiles also changed throughout fermentation. Further investigation should be conducted to clarify protein degradation dynamics during inoculated fermentations to define which of the microbial cultures positively affect the chocolate sensory characteristics. © 2021 Society of Chemical Industry.
Topics: Cacao; Chocolate; Fermentation; Flavoring Agents; Food Microbiology; Gas Chromatography-Mass Spectrometry; Humans; Pichia; Saccharomyces cerevisiae; Seeds; Taste; Volatile Organic Compounds
PubMed: 33421137
DOI: 10.1002/jsfa.11082 -
Foods (Basel, Switzerland) May 2023Traditional kombucha is a functional tea-based drink that has gained attention as a low or non-alcoholic beverage. The fermentation is conducted by a community of...
Traditional kombucha is a functional tea-based drink that has gained attention as a low or non-alcoholic beverage. The fermentation is conducted by a community of different microorganisms, collectively called SCOBY (Symbiotic Culture of Bacteria and Yeast) and typically consists of different acetic acid bacteria and fermenting yeast, and in some cases lactic acid bacteria that would convert the sugars into organic acids-mostly acetic acid. In this study, the effect of including a starter culture in a kombucha fermentation was investigated. additions led to a quicker accumulation of acetic acid along with the production of several acetate esters including isoamyl acetate and 2-phenethyl acetate. A subsequent tasting also noted a significant increase in the fruitiness of the kombucha. The significant contribution to the aroma content shows the promise of this yeast in future microbial formulations for kombucha fermentations.
PubMed: 37238757
DOI: 10.3390/foods12101938 -
Food Microbiology May 2022This study used a double-compartment fermenter to assess yeast growth, fermentation activity, and aroma production in response to cell-cell contact during mixed culture...
This study used a double-compartment fermenter to assess yeast growth, fermentation activity, and aroma production in response to cell-cell contact during mixed culture fermentation of Pinot noir grape must with Pichia kluyveri and Saccharomyces cerevisiae. Furthermore, amino acids were analyzed in order to study yeast interactions and possible reasons for aroma modulation as a response to cell-cell contact. Our results show that cell-cell contact between the two yeasts decreased cell viability of each yeast during mixed culture fermentation, and that it increased acetate and ethyl ester production and decreased varietal volatile levels. Moreover, it increased the consumption of glutamic acid and the biosynthesis of some specific amino acids related to cell growth, mainly histidine, glycine and proline, while suppressing the production of higher alcohols through the Ehrlich pathway. These results may contribute to an improved understanding, and thus control, of aroma production in mixed culture wine fermentations.
Topics: Amino Acids; Fermentation; Pichia; Saccharomyces cerevisiae; Wine
PubMed: 35082077
DOI: 10.1016/j.fm.2021.103960 -
Foods (Basel, Switzerland) Oct 2019Undesired fermentation of fruit-derived beverages by fungal, yeast and bacterial spoilage organisms are among the major contributors of product losses in the food...
Undesired fermentation of fruit-derived beverages by fungal, yeast and bacterial spoilage organisms are among the major contributors of product losses in the food industry. As an alternative to chemical preservatives, the use of and was assessed for antimicrobial activity against several yeasts () and fungi (, and ) associated with spoilage of fruit and fruit-derived beverages. The antagonistic properties of and were evaluated on cheap solidified medium (grape pomace extract) as well as on fruits (grapes and apples). Volatile organic compounds (VOCs) from and deemed to have antimicrobial activit were identified by gas chromatography-mass spectrometry (GC-MS). A cell suspension of and showed growth inhibition activity against all spoilage microorganisms studied. Direct contact and extracellular VOCs were two of the mechanisms of inhibition. Twenty-five VOCs belonging to the categories of alcohols, organic acids and esters were identified as potential sources for the biocontrol activity observed in this study. This study reports, for the first time, the ability of to inhibit fungal growth and also for to show growth inhibition activity against spoilage organisms ( = 6) in a single study.
PubMed: 31590435
DOI: 10.3390/foods8100454 -
Food Microbiology May 2022Table olive brines, inoculated with six different starters of lactic acid bacteria (LAB) or spontaneously fermented, have been used as isolating source of killer yeasts...
Table olive brines, inoculated with six different starters of lactic acid bacteria (LAB) or spontaneously fermented, have been used as isolating source of killer yeasts throughout the fermentation process (120 d). Killer yeast isolates were identified and evaluated for technological and probiotic traits. Although the count of yeast population did not markedly vary among the different vessels and over time, the killer yeast phenotype was mainly present in yeast strains isolated from spontaneous fermentation; the number of killer isolates decreased over fermentation time. Killer phenotype was found in species identified as Pichia kluyveri, Zygoascus hellenicus, Wickerhamomyces anomalus, Pichia membranifaciens, Candida boidinii, Candida diddensiae and Saccharomyces cerevisiae. Among all tested isolates, W. anomalus strains evidenced the widest spectrum of enzymatic activities and the highest β-glucosidase and phtytase activity. These strains evidenced also the best growth at low pH and increasing bile salt concentration, when grown at 37 °C, as well as the most constant viability index (%) during in vitro digestion.
Topics: Aptitude; Fermentation; Food Microbiology; Olea; Probiotics; Saccharomyces cerevisiae; Yeasts
PubMed: 35082067
DOI: 10.1016/j.fm.2021.103950 -
Journal of the Science of Food and... May 2024Higher alcohol acetates (HAAs) are potent aroma-active esters that impart desirable fruity and floral aromas. However, the conversion of higher alcohol precursors into...
BACKGROUND
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.
RESULTS
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.
CONCLUSION
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.
PubMed: 38690688
DOI: 10.1002/jsfa.13519 -
Archives of Microbiology Aug 2022The 'Kyoho' grape (Vitaceae, Plantae) has large ears, plenty of flesh, and rich nutrition and is planted across a large area in China. There are few reports on this...
The 'Kyoho' grape (Vitaceae, Plantae) has large ears, plenty of flesh, and rich nutrition and is planted across a large area in China. There are few reports on this variety in winemaking, especially on the dynamic changes of fungi in the wine fermentation broth. In this study, we used the 'Kyoho' grapes as raw materials and adopted a high throughput to analyze dynamic changes in fungal species composition of the natural fermentation broth at four time points: day 1 (D1P), day 3 (D3P), day 5 (D5P), and day 15 (D15P). Changes in fungal metabolic pathways and dominant yeasts were also analyzed. A total of 78 families, 110 genera, and 137 species were detected, in the natural fermentation broth samples. Forty-nine families, 60 genera, and 72 species were found in the control check (CK). A total of 66 differential metabolic pathways were enriched; of those, 41 were up-regulated compared to CK, such as CDP-diacylglycerol biosynthesis I (PWY 5667), chitin degradation to ethanol (PWY 7118), and the super pathway of phosphatidate biosynthesis (PWY 7411). Changes in fungal metabolic pathways were in line with the dynamic changes of dominant yeast species in the whole process of fermentation. Pichia kluyveri, P. membranifaciens, and Citeromyces matritensis are the dominant species in the later stages of natural fermentation. These yeast species may play vital roles in the 'Kyoho' wine industry in the future.
Topics: Fermentation; Fruit and Vegetable Juices; Humans; Vitis; Wine; Yeasts
PubMed: 35964278
DOI: 10.1007/s00203-022-03166-4 -
Food Research International (Ottawa,... Oct 2020This study attempted to achieve coffee flavour biotransformation through controlled fermentation of sterilsed green coffee beans with a coculture of Saccharomyces...
Coffee flavour modification through controlled fermentation of green coffee beans by Saccharomyces cerevisiae and Pichia kluyveri: Part II. Mixed cultures with or without lactic acid bacteria.
This study attempted to achieve coffee flavour biotransformation through controlled fermentation of sterilsed green coffee beans with a coculture of Saccharomyces cerevisiae and Pichia kluyveri (FYco) and a sequential inoculation of Lc. lactis subsp. cremoris and the yeast coculture (FLYco). Isoamyl acetate, 2-phenylethyl acetate, and ethyl octanoate were produced by 5.76, 1.35 and 0.54 mg/kg, respectively, in FYco fermented green coffee beans. Compared to the green coffee bean fermented by the yeast monocultures in previous study, FYco led to a 1.2- and 4.1-times elevation in production of isoamyl acetate and 2-phenylethyl acetate, respectively. FLYco further increased acetate ester production by more than 2 times relative to FYco. The esters produced in FYco and FLYco partially survived the roasting process and imparted the roasted coffees with considerable fruity and winey aromas. The lactic acid fermentation in FLYco increased the acidity in green coffee beans, which promoted the formation of caramel-smelling furfurals and preservation of acidity and sweetness in the roasted coffees. Apart from the mere additions of flavour modification from individual strains, the proper combination of multiple strains can result in synergistic effects that enhanced the modulating activities of individual strains and further enhance flavour complexity of the resulted coffee.
Topics: Coffee; Fermentation; Lactobacillales; Pichia; Saccharomyces cerevisiae
PubMed: 32846547
DOI: 10.1016/j.foodres.2020.109452 -
Foods (Basel, Switzerland) Oct 2022Viticulture is one of the traditional industries in Slovakia, where there are six wine-growing regions: Malokarpatska, Southern Slovakia, Central Slovakia, Nitra,...
Viticulture is one of the traditional industries in Slovakia, where there are six wine-growing regions: Malokarpatska, Southern Slovakia, Central Slovakia, Nitra, Eastern Slovakia, and Tokaj. This study focuses on the detection of microbiota in soil samples, grape leaves and berries, and samples taken from fermenting must and young wine (the variety Tramín červený) in relation to the detected concentrations of biogenic amines during the fermentation process. In the examined samples, the number of yeasts and molds (from 3.8 to 6.8 log cfu/g or mL) and TVC (from 3.7 to 6.5 log cfu/g or mL) were determined via culture examination. At the same time, the number of LAB (from ˂3.0 to 4.4 log cfu/g or mL) was determined, which was the highest on day 4 of the must fermentation process and was related to the detected of the highest concentration of biogenic amines (histamine and tyramine) on day 6 in the investigated must samples using the UHPLC system. Mycobiota species were identified by MALDI-TOF MS, PCR, ITS-PCR-RFLP, and PCR sequencing of the amplified products. The study confirmed the presence of the yeasts . At the same time, the presence of molds ( and ) was also confirmed in soil samples, leaves, grape berries, and fresh grape must. The study confirmed the reduction in the species diversity of the microbiota during the must fermentation process, which resulted in decreases in the concentrations of the monitored biogenic amines in the early stages of the must fermentation process and young wine of the variety Tramín červený.
PubMed: 36230137
DOI: 10.3390/foods11193061