Screening Of Non-Saccharomyces Cerevisiae In Henan Sour Dough And Its Application In Winemaking

Fermented pasta products made from traditional sour dough have better flavor and texture,mainly due to the rich strains of Saccharomyces cerevisiae and non-Saccharomyces cerevisiae within them.Non-Saccharomyces cerevisiae show great potential for improving the quality of sake,showcasing the terroir of sake and highlighting its personality.Its mixed fermentation with Saccharomyces cerevisiae is widely used in sake brewing to improve the sensory quality of sake.Cassava is very rich in nutritional value and high starch content,so using cassava as an auxiliary material for beer can save a lot of costs;cider is an alcoholic beverage made from fermented apple juice,and is one of the most popular apple fermentation products in the world.In this project,the non-Saccharomyces cerevisiae with "local" characteristics was isolated from Henan sour dough as the research object,and its species identification was carried out,and coupled with Saccharomyces cerevisiae for cassava beer and cider fermentation,to investigate the influence of non-Saccharomyces cerevisiae on the aroma complexity and safety of fermented wine,and to provide reference for the improvement of fermented wine quality.The main research results are as follows:(1)Two strains of high ester-producing non-Saccharomyces cerevisiae Y4 and M17 were screened out from Henan sour dough,of which Y4 produced 7.51 g/L of ester,65.34%higher than the control group;M17 produced 7.66 g/L of ester,68.47% higher than the control group;Y4 and M17 colonies were surrounded by cream color with blue-gray center,and the colonies were flat with milky protrusions around,with smooth and opaque surface;The strains Y4 and M17 were identified as abnormal Wickerhamomyces anomalus;the two non-Saccharomyces cerevisiae strains had good fermentation performance.(2)Using the screened non-Saccharomyces cerevisiae Y4 and M17 for cassava beer fermentation experiments,the results showed that: the alcoholic strength of the control group after fermentation was 5.14±0.09%vol,and simultaneous fermentation involving non-Saccharomyces cerevisiae M17(4.57±0.37% vol),Y4(4.56±0.10% vol)and sequential fermentation(4.78±0.25% vol)could complete the fermentation process well and did not affect the change in alcoholic content of cassava beer..A total of 7 biogenic amines and 21 amino acids were detected in the cassava beer from the seven fermentation methods.Different inoculations of non-Saccharomyces cerevisiaet and Saccharomyces cerevisiae did not change the composition of biogenic amines in cassava beer,but affected the content of biogenic amines,and monobacterial fermentation of non-Saccharomyces cerevisiae Y4 with M17 elevated the biogenic amine content of cassava beer;sequential inoculation of Y4 with Saccharomyces cerevisiae had the lowest biogenic amine content of 7.16 ± 0.30 mg/L,relative to the control group of 23.0%;Mixed fermentation of non-Saccharomyces cerevisiae with Saccharomyces cerevisiae reduced the biogenic amine content,and M17 significantly reduced histamine(61.9%)and spermidine(36.8%).A total of 99 volatile substances were detected in the cassava beer samples under seven fermentation methods,including 34 alcohols,25 esters,17 acids,8 terpenes,8 aldehydes and ketones,4 phenols and 3 others,with the alcohols citronellol,linalool,4-terpene alcohol,alpha-pinene alcohol,nerolidol,octanoic acid,sunflower acid,nonanal,furfural,geranyl acetone,4-ethyl guaiacol,etc.,which can provide different aromas and flavors to cassava beer and increase the flavor richness of the alcohol.(3)Cider fermentation experiments using the screened non-Saccharomyces cerevisiae Y4 and M17 showed that the highest alcoholic content was 7.64±0.01% vol in the control group and 8.58±0.25% vol in the non-Saccharomyces cerevisiae M17 fermented with Saccharomyces cerevisiae EC1118 in simultaneous inoculation,with a significant increase in the non-Saccharomyces cerevisiae M17 and Saccharomyces cerevisiae EC1118.A total of 8 biogenic amines and 20 amino acids were detected in the ciders from the 7 fermentation methods;the different inoculation methods of non-Saccharomyces cerevisiae and Saccharomyces cerevisiae did not The different inoculation methods of non-Saccharomyces cerevisiae and Saccharomyces cerevisiae did not change the composition of biogenic amines in cider,but affected the content of biogenic amines,non-Saccharomyces cerevisiae Y4 can reduce the total biogenic amine content to15.3%;the simultaneous inoculation and fermentation of Y4 and EC1118 can significantly reduce the content of putrescine(17.58%),guanidine butylamine(67.48%),spermine(33.33%),tyramine(74.75%),isopentamide(66.67%),histamine(60.62%)and ethanolamine(40.23%).A total of 89 volatile substances were detected in the cider samples from the seven fermentation methods,including 33 alcohols,20 esters,13 acids,5 terpenoids,11 aldehydes and ketones,2 phenols and 5others,were detected in the cider samples under the 7 fermentation methods,among which the alcohols were the most diverse and highest in content;the highest elevation was in Y4 sequential fermentation,which increased by 150.72% compared with the control group;the participation of non-Saccharomyces cerevisiae Y4 and M17 in fermentation could significantly increase or add 11 species,6 esters,3 terpenoids,2 acids and 4 others,including leaf alcohol,1-hepten-3-ol,6-methyl-1-heptanol,3-cyclopentyl-1-propanol,ethyl L(-)-lactate,ethyl palmitate,methyl salicylate,ethyl laurate,linalool,2-camphene,ethyl 9-decenoate,methoxyacetic acid,n-butyric acid,ethylene glycol ether,decanal,benzothiazole and 2H-pyran-2,6(3H)-dione,etc.