Study On Fermentation Process And In Vitro Function Of Germinated Quinoa Malt Paste

Quinoa belongs to Chenopodiaceae herb.As a kind of "super grain",quinoa is rich in nutrients and is a high protein,low calorie food,and it is also rich in active substance.Quinoa seeds are easily germinated under suitable conditions,and germination changed the nutritional content of quinoa,which further enriched the nutritional value of quinoa.Quinoa is currently used in food mainly in the form of breakfast porridge,quinoa flour,dessert and the like.Quinoa malt is used as raw material for fermented beverage,which not only preserves the original nutrition value of quinoa,but also has the health benefits of probiotic fermented products.The product provide a breakthrough point for quinoa research and development of new ways.In this paper,Shanxi Jingle quinoa is used as raw material,through appropriate conditions to promote its short-term germination.Study on dynamic nutrients changes of quinoa during germination in order to determine the appropriate germination time.The obtained quinoa malt is subjected to be refined,and on the basis,mixed lactic acid bacteria are fed into the quinoa malt paste to be fermented.Through the establishment of a simulated digestion model in vitro,the effects of simulated digestion and fermentation on the digestibility and antioxidant activity of quinoa malt paste were studied to provide theoretical basis for the nutritional value of the quinoa malt fermented paste.The results are as follows:1.Determination of different germination time quinoa malt main nutrients changes.The germination process of quinoa malt protein content increased first,germination began to decline after 24 h.Starch content has been reduced,reducing sugar content continued to increase,polyphenol content increased first and then decreased.According to the change of the content of quinoa malt in the process of germination,the best time for quinoa germination was selected as 24 h.On the basis ofsingle factor experiment,orthogonal experiment design method was used to determine the conditions of refining,the protein extraction rate and polyphenol extraction rate of quinoa malt paste are used as an indicator.Result showed that the best refining time is 1.5min,the refining temperature is 60 ? and the material to liquid ratio is 1:6.The quinoa malt paste was gelatinized,and the optimum gelatinization conditions were as follows: gelatinization temperature 80 ?,gelatinization time 50 min.2.Taking quinoa malt as raw material,the effects of fermentation conditions on the lactic acidity and viable count of quinoa malt paste were studied.Two strains of Lactobacillus plantarum and Lactobacillus casei were used for fermentation.Single factor experiment and response surface optimization analysis were used to explore the effect of the proportion,inoculation amount and fermentation time on fermentation.The results showed that the optimum fermentation conditions of quinoa malt fermented paste were as follows: proportion of Lactobacillus plantarum and Lactobacillus casei 2.5:1,inoculation amount 3% and fermentation time 10.3 h.The lactic acidity of the germinated quinoa malt fermented milk was 85.32 °T and the viable count was 9.21 logCFU/mL,which was in agreement with the predicted value.The result showed that the homogenized fermentation of quinoa malt medium is suitable for the growth of lactic acid bacteria.3.The quinoa malt paste were co-digested using an in vitro model of gastrointestinal digestion.The proteolytic degree,the content of reducing sugar,polyphenol and flavonoids of the fermented paste were determined compaired with unfermented paste.The result showed that after pepsin digestion,relative to unfermented paste,the protein hydrolysis of quinoa malt fermented paste increased by 23.28%,which increased by 17.14%following simulated intestinal digestion.After fermentation,the RDS and SDS contents of the quinoa malt paste increased by 21.22% and 5.14%respectively,and the RS content decreased by 26.23%.The contents ofpolyphenols and flavonoids increased significantly after digestion,which increased obviously in simulated intestinal digestion.The polyphenol of the fermented paste was fully released.After fermentation,the digestive characteristics of quinoa paste increased.4.This section mainly studies the antioxidation activity of fermentation and digestion on the quinoa malt paste by DPPH free radical,hydroxyl radical,superoxide anion free radical scavenging rate and iron reducing ability and total antioxidant capacity.The results showed that the antioxidant activity of the fermentation group and the digestion group was significantly higher than of the unfermented group.And the antioxidant activity of the digestion group was the highest.