Study On The Extraction Of Chinese Yam Polysaccharide And Polyphenol And The Fermentation Technology Of Chinese Yam Milk Wine

Yam,called Dioscorea opposita Thunb.Has long history in China with excellent medical and health care function.Yam has middle level,sweet taste and health functions,such as invigorating kidney.Yam is very popular in the China and is planted in the middle-of-south and southwest of China,such as boai,qinyang,wuzhi,wenxian in Henan province and is cold-resistant and yoshimitsu.Yam is comprised of polysaccharides,many kinds of amino acid,mineral substance,polyphenols,flavonoids and so on.So Chinese yam has much bioactivities,for example,anticancer,antibacterial,anti-age,maintaining beauty and keeping young.Thus yam can treat cough,cardiovascular and cerebrovascular diseases,inappetence et al.Therefore yam had been used for preventing kinds of diseases in ancient times.Yam polysaccharides and yam polyphenols can be extracted by refluxing method,microwave technology,ultrasonic wave technology,supercritical fluid extraction,subcritical extraction.Yam polysaccharides is main bioactive molecules which has much activities,such as antioxidant,anticancer,anti-age,anti-fatigue.In the brewing process,milk liquor can’t be destroyed the nurtritional substance of the milk.Milk is refined,removed fat,puritied,fermented.Then,the nutrients can be activated and absorbed very well.Milk liquor is riched in 18 kinds of amion acids,much victamins,mineral substance.And the content of victamin in milk liquor is higher than milk.The quality of milk wine was affected by the addition of yeast,pH,temperature,time.Thus,in this paper,we researched the yam polysaccharides extraction and polyphenol extraction.Then we also researched the yam milk liquor process and chosed the optimal technological conditions.The results were as followed:（1）The experiment is about yam polysaccharides from dioscorea opposita Thunb tuber with extraction ultrasonicwave technology.Some factors which influenced yield of yam polysaccharides were researched with single factor experiment and orthogonal test methodology.Finally,the maximum yield of yam polysaccharides from dioscorea opposita Thunb was 5.32%with ultrasonic time was 20 min,ration of material to liquid was 1:28（g/mL）and ultrasonic power was 750 W.（2）The experiment is about yam polyphenols from dioscorea opposita Thunb tuber with microwave extraction technology.Some factors which influenced yield of yam polysaccharides were researched with single factor experiment and orthogonal test methodology.Finally,the maximum yield of yam polyphenols from dioscorea opposita Thunb was 4.29 mg/g with microwave time 7 min,ethanol concentration 60%,ration of material to liquid 1:10（g/m L）.（3）The alcoholic fermentation of yam pulp was produced by using three kinds of yeasts respectively,Angela wine yeast,Saflager beer brewing Lager dry yeast and Dan polly wine highly active dry yeast.We used alcoholic strength as the result index and choose the yeast with shorter fermentation time,higher alcoholic intensity and richer wine for subsequent experiments.At last,the dry yeast Saflager was the most yeast for yam milk liquor when the addition of dry yeast Saflager was 0.3%,pH was 3.5,fermented temperature was 30℃.（4）The experiment is about milk liquor process.Some factors which influenced the quality of yam milk liquor were researched with response surface methodology.Finally,we gained binary multiple equations and the mode is very significant.The binary multiple equationswas:Y=42.579+0.693X₁+0.702X₂+0.696X₃+0.942X₄-0.902X₁²-0.365X₁X₂-0.399X₁X₃-0.0947X₁X₄-0.885X₂²-0.208X₂X₃-0.386X₂X₄-1.18X₃²-0.264X₃X₄-0.985X₄².The maximum yield was8.98%vol When the addition of yeast was 0.28%,fermented temperature was 30℃,ration of yam to milk was 3.1:1（V/V）and pH was 4.3.