Research And Development Of Fermented Grains With Mixed Strains

Cereal-based fermented beverages are generally produced with both the nutritional content of cereals and microbial source functional components.During this study,Lactobacillus and Geotrichum candidum were used as fermentation strains to develope two kind of beverage with unique flavor-Soybean fermentation drinks and red bean barley milk drinks.The main contents are as follows:(1)Soybean and milk used as raw materials,while sucrose partly instead of inulin and isomaltulose,the low-sugar fermented soybean milk was developed by co-fermentation with Lactobacillus and Geotrichum candidum.This technology is intended to broaden the usage scope of raw materials,and also reduce the cost of fermented milk.(2)Through the activation and acclimation of Lactobacillus and Geotrichum candida,as well as the study on the stability of soymilk fermentation,one unique fermentation process was obtained.Specially,various kinds of acid,esters,aldehydes and aromatic substances produced by Geotrichum candidum,could cover up the flavor of soybean.Furthermore,the extracellular polysaccharide produced during the fermentation process,could increase the viscosity of yogurt,greatly reducing the use of stabilizers.Using the content of extracellular polysaccharide as the index,the optimum conditions of the fermentation were as follows:the ratio of Lactobacillus to Geotrichum candidum was 2:5,the inoculation amount was 7%,the fermentation temperature was 30?,and the fermentation time was 8 h.The effects of various stabilizers,such as xanthan gum,pectin,CMC-Na and guar gum,on the stability of fermented soybean milk beverage were investigated.The optimum ratio of xanthan gum,pectin and CMC-Na were 0.23%,0.1%and 0.27%,respectively.GC-MS was used to analyze the volatile substances produced by the fermented strains.The results showed that the content of aromatic substances were three times higher than that of non-fermented ones.(3)Red bean and barley used as raw materials,one kind of health beverage was developed with the health function of red bean,barley and yoghurt.The optimal conditions was determined by response surface analysis.And the optimal fermentation conditions were as follows:the inoculation amount of Lactobacillus and Geotrichum candidum was 6%,the?fermentation time was 6 h,the fermentation temperature was 30?,and the proportion of two kinds of microorganism was 1:1.The best proportions of red bean milk,barley milk,sucrose and citric acid were 30%,20%,3%and 0.85%,respectively.And the optimal amount of CMC-Na and xanthan gum were 0.3%and 0.4%.