Effect of Corn Starch's Transformation Rate on the Quality of Papaya Wine

The purpose of this experiment was to study the effect of corn starch's transformation rate on the quality of papaya juice and discuss the its role in the fermentation process of papaya juice. Papaya grown in Lincang was taken as experimental material. During the period of 2017-2018, five repetitive experiments on gelatinization, liquefaction and saccharification of maize starch were carried out, respectively. Pure saccharified liquid, fermentable sugar used by yeast, was extracted by coarse filtration of gauze and filtration of suction filter. In 2017, the activity conditions of alpha-amylase and glucoamylase were determined. Four different saccharification methods including double enzymatic method, acid hydrolysis method, enzymatic hydrolysis method and acid enzymatic method were selected for experiments, respectively. The optimum method on saccharification of corn starch was determined according to the sugar content and yield of saccharified solution. The saccharified liquid obtained was added to peeled and non-peeled papaya juices for fermentation, respectively. During the experiment, the quality indexes, such as total sugar, total acid, tannin, anthocyanin and chroma were determined, respectively. In 2018, the transformation experiments of corn starch in corn flour, fresh corn granules and mature corn granules were meanwhile carried out. The best raw material for saccharification was selected through the total sugar content and the extraction rate of saccharification solution. The optimum conditions of enzyme activity were determined as pH 6, temperature 70 degrees C in a-amylase, pH 5 and temperature 60 degrees C in saccharifying enzyme. The yield of saccharified solution of mature corn granules was 60%, the sugar content was 193.64 g/L. The double enzymatic saccharification obtained 46 g/L sugar content and 46.60% yield of saccharified solution. Therefore, mature maize granules with double enzymes method were the best choice for saccharification experiments, which increased not only the sugar content and the yield of saccharified solution, but also made the operation simple and filter easy. The saccharified liquid extracted by mature corn granules combining with double enzymatic method could promote the fermentation of papaya wine, which, on the one hand, could protect the color of papaya wine, on the other hand, improve the flavor of papaya wine, and make papaya wine with unique honey and caramel flavor.