Application Of Lactiplantibacillus Plantarum LP315 In Fermented Milk

In this experiment,Lactiplantibacillus plantarum LP315 was used as the main object of study and fermented with Stretpococcus thermophilus S10 in different proportions.The optimal mix ratio was determined by analyzing ac idity,water retention,texture,viable bacteria count and sensory evaluation at storage 1d.On this basis,the storage stability and the variation rule of fermentation metabolites of the optimal mixture ratio fermented milk were investigated,which provid ed a theoretical basis for the development of Lactiplantibacillus plantarum fermented milk.The main conclusions are as follows:(1)In the different ratio composite groups,L.plantarum LP315:S.thermophilus S10=1:1(group A1)reached the fermentation destination at about 6h.After 1 day of storage,the p H and titrated acidity of group A1 were 4.26 and 104.33°T,respectively,and the water retention was 54.63%.The bacterial viable counts in group A1 was the highest,in which L.plantarum LP315 and S.thermophilus S10 were 7.14 and 8.96 Log(CFU/m L),respectively;all parameters and sensory scores of the texture of group A1were superior to the other combinations,and this ratio was subsequently used as a composite group for fermentation.(2)Compared with the L.plantarum LP315 monoculture group and S.thermophilus S10 monoculture group,the composite group showed smooth and delicate tissues,moderate sweet and sour,and the highest sensory scores throughout the storage period,and the viable counts were higher than those of the monoculture group,and they all remained above 1×10~8 CFU/m L at the end of storage.(3)The metabolic analysis of the samples from the compound group and the monobacterial group at the end of fermentation and the 21 st day of storage showed that the metabolites in the compound group were more abundant than those in the monobacterial group,and the contents ofα-linoleoylethanolamine,phenylalanine,leucine,and lacto-N-tetrasaccharide were higher in the compound group than in th e monobacterial group,and these metabolites could improve the taste and texture of fermented milk,enhance human immunity,and give more nutritional value and probiotic effects to fermented milk.In conclusion,compounding L.plantarum LP315 as a co-fermentor with S.thermophilus S10 in a 1:1 ratio to ferment cow’s milk was able to improve the sensory and texture of the fermented milk,which provided data to support the future application of L plantarum in fermented milk.