Screening Of Deacidification Yeast Strains And Application For Fruit Wine Fermentation

Citric acid and malic acid are important organic acids affecting the quality of the fruit wine.In order to obtain strains for citric acid and malic acid degradation and apply them to different fruit wine fermentation,130 non-Saccharomyces yeast strains were screened according to their deacidification capacity of citric acid and malic acid,and the corresponding fermentation characteristics of kiwi fruit wine and red wine,respectively.The main results are as followed:1.One hundred and thirty non-Saccharomyces yeast strains were screened according to their citric acid-degradation capacity and fermentation characteristics.The results demonstrated that eight non-Saccharomyces yeasts named M100,M130,B9S-2,B6-1,B4-19,GS1-1,GS1-20 and M1-1 exhibited good deacidification capacity and fermentation characteristics,and the citric acid-degradation rate ranged from 15.04% to 22.52%.Among them,I.orientalis M130 was evaluated as the best strain.In addition,the changes of organic acid were monitored during the fermentation process.The results showed that citric acid was decreased gradually,and the citric acid-degradation reduced when the concentration of malic acid was high.And the capacity convert citric acid to succinic acid of Issatchenkia orientalis was stronger than Saccharomyces cerevisiae.2.During kiwifruit fermentation,M130 with excellent degradation capacity and fermentation characteristics was obtained.In this study,the strains M100,M130,B9S-2,B6-1,B4-19,GS1-1,GS1-20,M1-1 were brewed with kiwi fruit wine.Among them,M130 strain was evaluated as the best strain in kiwi fermentation trials for its high deacidification rates(18.12%),responsible for citric acid degradation from 13.12 g/L to 10.74g/L in kiwi fruits,and the final wine exhibited transparent wine body and rich fragrance.3.Twenty non-Saccharomyces yeast strains were screened according to their malic acid-degradation capacity and fermentation characteristics and nine strains of M100,M130,B9S-2,B6-1,B4-19,GS1-1,GS1-20,M1-1 and GS1-18 behaved with good deacidification capacity and fermentation characteristics were selected.The malic acid-degradation rate ranged from 33.52% to 44.7%.Among them,strain M1-1(I.orientalis)was evaluated as thebest strain for its malic acid degradation range from 11.12 g/L to 6.19 g/L.The organic acid was monitored during the fermentation process,the results showed that malic acid showed a tendency with rising first and then decreasing.The metabolism of malic acid was promoted with low concentrations of glucose(20 ~ 60 g/L)according to fermentation curves.4.To obtain strains for high acid grape wine fermentation,the strains M100,M130,B9S-2,B6-1,B4-19,GS1-1,GS1-20,M1-1 and GS1-18 were used for high acid Cabernet Sauvignon must fermentation.Among them,M1-1 strain was evaluated as the best strain in wine fermentation trials for its high deacidification rates(66.09 %),responsible for malic acid degradation from 3.32 g/L to 1.13 g/L.And strain M130 also showed good degradation of malic acid 37.18 %.In conclusion,M130 is the significant strain for the study of acid degradation in fruit winemaking beacuse of its good degradation capacity of citric acid and malic acid.