Optimization Of Persimmon Wine Brewing Conditions And Application Of Non-Saccharomyces Cerevisiaes In The Fermentation

Persimmon is native to China and is one of the important fruits in our country.Persimmon cultivation is extensive,the yield of main product area,such as Guangxi,Hebei,Henan,and Shaanxi accounts for about half of the country's production.Persimmon fruit is rich in nutrients and has certain edible and medicinal value.It is known as the“fruit in the fruit”.Based on the nutritional value of persimmon,persimmon can be used as a raw material to ferment high quality persimmon wine,which not only can make full use of Chinese persimmon resources,reduce resource waste,but also meet the market demand and bring certain growth to the local economy.In this study,persimmon was used as a raw material to brew fruit wine,the process conditions such as the persimmon juice digestion,persimmon alcohol fermentation and persimmon wine clarification were optimized to enhance production efficiency.At the same time,non-Saccharomyces cerevisiae was introduced during fermentation.The performance of non-Saccharomyces cerevisiae was studied in persimmon wine fermentation.The effects of non-Saccharomyces cerevisiae and Saccharomyces cerevisiae on the flavor of persimmon wine were investigated.The main research contents and results are as follows:?1?Effects of mix enzymolysis and saccharification of Daqu on juice yield and reducing sugar content of persimmon.The fresh persimmon fruit from Bin County,Shaanxi Province,was used as a raw material to extract persimmon juice through artificial ripening,compound enzymolysis,Daqu saccharification and many other steps.The technological conditions of the compound enzymolysis and Daqu saccharification were optimized by orthogonal experiment.When the extraction conditions are the pectin enzyme dosage of 0.03%,cellulose enzyme dosage of 0.015%,enzymolysis temperature at 50?,the persimmon fruit pulp was enzymolysized for 2.5 h,the enzymolysize juice was obtained.Then under the conditions being Daqu dosage of 2wt%,saccharification temperature at 60?,the obtained juice saccharification for 2.5 h,the persimmon juice yield could reach to 64.43%,the reducing sugar content is 120.27 g/L.The rate of juice and reducing sugar content increase by 25.85%and 51.87%respectively,compared to the juice rate from non-enzymolysis and non-saccharification.And other nutrients are remained unchanged.?2?The optimization of fermentation and clarification of persimmon wine.The optimum conditions for the fermentation of persimmon wine were determined by single factor and orthogonal experiment to be the yeast inoculum of 0.2%,the nutrient dosage of 0.2 g/L,and the fermentation temperature of24?,under these conditions,the alcohol fermentation efficiency was the highest in the tests,the alcohol volume fraction reached 11.76%.The optimal combination of clarifying agent for persimmon wine was 0.4 g/L chitosan,0.4g/L gelatin and 0.6 g/L PVPP,under the condition,the light transmittance of persimmon wine could reach to 97.88%.?3?Study on the performances of non-Saccharomyces and saccharomyces cerevisiae in persimmon wine mix-fermentation.Basing on the abilities of non-Saccharomyces cerevisiae metabolites to enhance fruit wine with more aroma and flavor,two types of non-Saccharomyces cerevisiae,Klockera apiculata and Issatchenkia orientalis were introduced into the fermentation of persimmon wine.In this study,the tolerances of non-Saccharomyces yeasts to ethanol,SO₂,tannin and the abilities to secrete?-glucosidase were investigated,at the same time,the fermentation performance of the single non-saccharomyces yeast and mixed saccharomyces cerevisiae were also studied.The results showed that I.orientalis was better than the K.apiculata on the abilities of tolerance to ethanol,SO₂,tannin,but the ability to secrete?-glucosidase was weaker.Two non-Saccharomyces cerevisiae had poor fermentation abilities.The alcohol contents of the fruit wine fermented by K.apiculata and I.orientalis could only reach to 3.05%vol and 4.51%vol respectively.Whereas,all the types of mixed yeasts of non-Saccharomyces cerevisiae and Saccharomyces cerevisiae had much better fermentation abilities than non-Saccharomyces cerevisiae.After seven days fermentation with mixed yeast,a Persimmon wine with more than10%?vol?alcohol content could be brown.?4?The effect of different yeast fermentation on the flavor substances of persimmon wine.The volatile components in the samples were extracted by head space solid phase micro extraction?HS-SPME?.The GC-MS was used to analyze the flavors in wine fermented by different fermentation methods.The results showed that the K.apiculata yeast could produce more flavoring substances,the fruity aroma is rich;whereas the I.orientalis yeast produce high yield of ethyl acetate,giving wine a bad aroma similar to ether,the wine fermented by a single Saccharomyces cerevisiae was with a single flavor,and heavy flavor of alcohol,the mixed fermentation of non-Saccharomyces cerevisiae and Saccharomyces cerevisiae could increase the diversity of aroma components and improve the quality of fruit wine.By optimizing the brewing conditions of persimmon wine,the utilization rate of the raw materials and production efficiency can be improved.Non-Saccharomyces cerevisiae has a positive effect on improving persimmon wine flavor,which has certain reference value for the further development of fruit wine resources.