Study On Screening And Stability Of Mulberry Wine Yeast

Under the background of development research on old mulberry woodlot of Yellow River forest park, Xia Jin.This topic was proposed to increase the added value of mulberry and provide new ideas for the transformation of mulberry industry. Research team selected White Jade as the raw material, which was the unique old mulberry of old mulberry woodlot of Yellow River forest park, Xia Jin, Shan Dong, discussing the preparation technology of mulberry industrialization squeezing. Also, we studied the fermentation characteristics of three original excellent fruit wine brewing yeast those saved in the laboratory, to screen the best fermentation strain. As the next step, we employed orthogonal test on the basis of the above single factor experiments of fermentation conditions, to study which factors those the strain influenced the brewing of mulberry fruit wine and get the optimum parameters of producing mulberry fruit wine.What was more, we studied the precipitation phenomenon in late storage period of mulberry fruit wine, through the study on five kinds of clarifying agent, comparing their clarification effect.We chose a suitable solution for clarification of mulberry fruit wine. The main results were as follows:1. Mulberry industrialization squeezing process:mulberryâ†'spiral broken press into the hopperâ†'extrusionâ†'separationâ†'mulberry fruit juiceâ†'fruit pulp pumpâ†'standby; during the storage, the SO2 content of 80 PPM. The final compound enzyme was 140 u/g.2. Yeast strains screening:through contrast test of three yeast strains, the yeast strain Y1 was good for mulberry fruit wine fermentation. Several experiments showed that Y1 strain had several good aspects, which were exuberant fermentation, and smooth fermentation process and quickly achieving exuberant fermentation period, also relatively less quantity of bacteria colony; and sugar consumption used for its growth metabolism was less, it could produce higher alcohol content, base liquor tasting scores were the highest.3. The optimization of fermentation process parameter. Firstly, the single factor experiments were undertook, which were inoculation amount, the initial pH value of fermented liquid, sugar value, fermentation temperature and the amount of (NH4)2SO4, then, using the method of orthogonal experiment to optimal parameters, we got the best process conditions:fermentation temperature of 20℃, inoculation amount of 8%, initial pH value of 3.4, sugar was 21%, the amount of adding nitrogen source was 2 mg/L, the fermentation cycle for 7 d.4. The optimization of clarifying process conditions:single clarifying agent (the best adding amount):egg white powder of 5/ten thousand, chitosan of 2.5/ten thousand, gelatin of 4.0μL/100mL, bentonite of 9.0/ten thousand, diatomite of 4.5/ten thousand. Among those clarifying agents, the bentonite was the best choose to clarify mulberry base liquor. Compound clarifying agent:bentonite content of 7.0/ten thousand and gelatin content of 4.5μL/100 ml; or bentonite of 7.0/ten thousand and chitosan of 2.5/ten thousand; or Gelatin 3.5μL/100 ml and chitosan content of 2.5/ ten thousand. The composite clarifying agent (bentonite and chitosan) was the best choose, the light transmittance of mulberry base liquor could reach as high as 94.7%. The clarification effect of compound clarifying agent was much better than single clarifier. The experimental results showed that the light transmittance of mulberry base liquor treated with composite clarifying agent (bentonite and chitosan) can reach 94.7%, alcohol content was 11.4 degrees, total sugar content was 2.51 g/100mL, total acid was 6.55 g/L, total sulfur dioxide of 150 PPM or less, total bacterial colonies of 20/mL or less, coliform group of 1/L or less, pathogenic bacteria was not detected.