Quality Evaluation Of Several Mulberries In Xinjiang And Optimization Of Mulberry Wine Production Technology

Mulberry fruit is full and juicy,with elegant aroma and bright color.It is a high quality raw material for brewing fruit wine.Southern part of Xinjiang province is one of the famous mulberry producing areas in China.There are many kinds of mulberry,mainly white and fuchsia.The fuchsia has a sour taste,Medicine mulberry is the only natural wild variety of 22 ploidy planted in China,and is widely used as a Uygur medicine because of its special pharmacological effects.In this study,the physico-chemical indexes antioxidant activity of seven main fruit mulberry varieties in southern Xinjiang were determined and analyzed.According to the quality analysis results of mulberries,three kinds of mulberries were selected for mixed fermentation to produce mulberry wine.The yeast strains of mulberry wine were selected and the fermentation technology of mulberry wine was optimized.On this basis,the mulberry brandy was further distilled,and the physicao-chemical indexes,bioactive components and volatile flavor substances of the two products were determined,which provided technological and theoretical basis for enriching the fruit wine industry,realizing the standardized production of mulberry wine in Southern Xinjiang and the development of health fruit wine.All of the results were as follows:(1)To understand the quality differences of several main mulberry in Xinjiang and screen mulberry varieties suitable for wine making,seven main mulberry varieties in southern Xinjiang were selected as materials,and the indexes of moisture,p H,total sugar,total acid,reducing sugar,total phenol,total flavonoids,procyanidins,antioxidant activity were measured.The results showed that there were significant differences in physico-chemical components of seven kinds of mulberry fruits(P<0.05),and the moisture content of Ziyu No.1 mulberry was the highest(89.62%).The total acid content of Medicinal mulberry was the highest(1.86%).Great white mulberry has the highest total sugar and reducing sugar(17.39%and 8.58%),respectively.The Little black mulberry has the highest Vc(0.35 mg/g),crude fat(2.83%)and crude protein(1.93%).The contents of total phenols,total flavonoids and procyanidins in Ziyu No.1 were 17.09 mg GAE/g DW,12.46 mg RE/g DW and 3.47 mg/g DW.The results showed that the seven fruit mulberry varieties were rich in nutrients.The Great white mulberry had the highest total sugar content,Ziyu No.1 had the highest total phenolic,total flavonoid and proanthocyanidin content,and Little black mulberry had the highest antioxidant activity and total acid content.According to the above analysis results of physico-chemical components,combined with the cultivation and yield of several mulberries in Xinjiang,three varieties of Great white mulberry,Ziyu No.1 and Medicinal mulberry were selected as the main raw materials for brewing mulberry fruit wine.(2)Three commercial yeasts DV10,EC1118 and F33 were selected to optimize the fermentation process of mulberry fruit wine through single factor and orthogonal experiments.The effects of mulberry ratio,initial sugar content,addition amount of potassium metabisulfite and yeast inoculum on the quality of mulberry fruit wine were studied.The results showed that using DV10 yeast,when the initial sugar content was 24%,the ratio of raw materials was 1:1:3,the addition amount of potassium metabisulfite was 40mg/kg,and the yeast addition amount was 200 mg/kg,the wine fermentation showed the best results.In this condition,the alcohol content of the product was 12.06%vol,sugar content was 4.07%,total acid was6.56 g/L,SO₂was 24.32 mg/L,methanol was 97.88 mg/L,p H 4.21,phydroxybenzoic acid 12.96 ng/m L,procyanidin 434.89 ng/m L,epicatechin 89.86 ng/m L,anthocyanin 3-O-rutinoside was 206.63 ng/m L,anthocyanin 3-O-glucoside was 443.41 ng/m L,chlorogenic acid was 27.39 ng/m L,rutin was 40.79 ng/m L,and the average sensory score was 83.67.(3)The obtained fermented liquid was distilled to obtain mulberry brandy,and the volatile flavor substances and physical and chemical indexes of the two products were determined.The results showed that the alcohol content of mulberry brandy was 52.58%vol,cyanide content was 0.047 mg/L,SO₂content was 106.24 mg/L,methanol content was 154.67 mg/L,lead and copper were not detected.The two products have a total of 103 volatile components.There are 15 kinds of alcohols,49 kinds of esters,10kinds of acids,12 kinds of aldehydes and ketones,2 kinds of terpenes,and 11 kinds of other volatile components.The total content of volatile flavor substances in the two products is 228.473?1561.00 mg/L,esters accounted for 44.52%and 83.91%of the total flavor substances of the two products,respectively.The organic acid content of the two products only accounts for 0.61%?0.18%of the total product flavor substances.The mulberry brandy prepared under this process has a mellow taste and elegant flavor,which lays a theoretical basis for enriching the fruit wine industry.