Effects Of Lactobacillus Casei Zhang And S.thermophilus Mixed Fermentation On The Sensory Quality Of Fermented Milk

With the development of social needs,researchers have made in-depth research on commercial yogurt starter,which has led to more and more kinds of fermentation products and more and more stable quality.Howevers there are still some problems and shortcomings in China.At the present stage,most probiotics on the market in China are purified from foreign human bodies or dairy products.Moreover,the flavor of yogurt fermented by commercial leavening agents is relatively single,which cannot fully meet the taste demands of consumers.Current most dairy products adopt yoghurt starter cultures is relatively single,less product variety,fermentation time is longer,the production cost is higher,also easy to infection by a phage may produce,so the urgent need for new strains of filtration and separation,further research and further understanding candidate strain characteristics can help to improve the stability and safety products.Therefore,21 strains of S.thermophilus were selected for the research,and the fermented milk was prepared by activation and culture,and the superior S.thermophilus strain was selected by evaluating the sensory quality of the fermented milk in terms of appearance,odor,flavor and texture.Select excellent S.thermophilus strains with L.casei Zhang strains tested,separately S.thermophilus strains,L.casei Zhang strains and S.thermophilus strains with L.casei Zhang strain distribution in fermented dairy products,the storing period(4?),28 d three different strains fermented dairy products in physical properties,the number of living bacterium,the sensory quality of different,the statistical number of living bacterium.The results show that:1.The fermentation characteristics of 21 strains of S.t hermophilus were comprehensively compared and analyzed from four dimensions of texture,flavor,odor and appearance.2.L.casei Zhang was mixed with S.thermophilus B3 for fermentation,and the probiotics L.casei Zhang had no significant correlation with the fermented milk samples in terms of acidity,viscosity and dehydration contractibility,which did not affect the viable number of S.t hermophilus,but promoted the growth of L.deLrueckii subsp.Bulgaricus,and improved the flavor and quality of fermented milk.Meanwhile,the stability of L.casei Zhang in fermented milk was found to be good,so the hybrid fermentation of probiotics L.casei Zhang and S.t hermophilus was suitable for production.