Study On The Breeding Of Wickerhamomyces Anomalus And Its Application In Low Alcohol Cider And Kiwi Wine

The annual production and consumption of fruit wines in China are increasing at a rate of about 15%.The rapid development of the fruit wine industry is conducive to solving the structural,regional and seasonal situation where the supply of fruit exceeds demand in China and promoting regional economic development.In recent years,the quality of fruit wines in China has been greatly improved,but objectively speaking,there is a lack of aroma,the flavour is usually thin,and the body is more unstable.An increasing number of studies have shown that some non-Saccharomyces cerevisiae yeasts can improve the quality of fruit wines and increase the intensity and complexity of their aromas.In this study,the indigenous Wickerhamomyces anomalus C732 was first mutagenised using the ARTP technique to obtain a faster fermentation rate,and then the mutant strain was blended with the Saccharomyces cerevisiae CECA to produce low alcohol cider and kiwi wine.（1）Using atmospheric room temperature plasma mutagenesis,W.anomalus was selected for a faster starting fermentation rate.1218 mutagenic strains were collected and conserved with a 90%lethality rate for ARTP mutagenesis.Six mutant strains with significantly higher biomass than the original strains were screened by using sterile 24-well plates to simulate fermentation using the OD_600nm as the primary screening index.The fermentability,tolerance and hydrogen sulphide production were further evaluated,and three strains of Wa-2-84,Wa-2-85 and Wa-B1-8 were finally obtained,which were faster fermenting,more tolerant and low H₂S producing.（2）W.anomalous and accompanying brewing process was obtained for production of high quality,low alcohol cider.Three strains of W.anomalous were inoculated simultaneously with the S.cerevisiae in a 5:1,1:1 and 1:5 inoculation ratio respectively to ferment ciders（400m L brewing system）.The results showed a significant increase in the aroma compound content of the cider fermented in a 1:1 inoculation ratio compared to CECA alone fermentation,with an enhanced fruity and floral aroma profile and no nail polish-like chemical odour.The cider making system was further scaled up to 10 L,three strains of W.anomalous were each inoculated with CECA at a 1:1 inoculation ratio to ferment the ciders.The results showed that the simultaneous inoculation and fermentation of CECA with Wa-2-85（SW-5）resulted in ciders with the highest content of aroma compounds,high aroma intensity,good coordination and enhanced fruit and floral characteristics.Therefore,it was shown that S.cerevisiae CECA,inoculated simultaneously with the W.anomalous Wa-2-85 in a 1:1 ratio,is suitable for use in the aromatization of low alcohol ciders.（3）W.anomalous and accompanying brewing process was obtained for production of high quality,low alcohol cider.Three strains of W.anomalous were inoculated simultaneously with the S.cerevisiae in a 5:1,1:1 and 1:5 inoculation ratio respectively to ferment ciders（400m L brewing system）.The result showed that the kiwi wines fermented with a 1:5 ratio of S.cerevisiae and abnormal W.anomalous inoculated in a 400 m L fermentation system had the highest content of acetate,enhancing fruit and floral aromas such as pineapple and passion fruit.The cider making system was further scaled up to 10 L,three strains of W.anomalous were each inoculated with CECA at a 1:1 inoculation ratio to ferment the kiwi wines.The results showed that mixed fermentation increased the content of all five organic acids and glycerol in the kiwifruit wine compared to CECA alone fermentation,and that the aromatic characteristics of passion fruit,pineapple,white flower and honey were enhanced in the kiwifruit wine fermented with a mixture of W.anomalous and S.cerevisiae.QDA analysis of the kiwi wines showed that SW-4（CECA:Wa-2-84=1:5）had the highest aroma intensity and better coordination.Wa-2-84 is therefore more suitable for the aromatic fermentation of kiwi wine than the other two strains of W.anomalous,and is fermented in a 1:5 ratio of S.cerevisiae to W.anomalous.