Research On The Application Of Lacticaseibacillus Paracasei PC646 In Active Fermented Soy Milk Beverage

In this research,Lacticaseibacillus paracasei PC646 and Lacticaseibacillus paracasei PC-01 were used as fermenting bacteria to prepare active fermented soymilk beverages.The stability of the beverage was analyzed by changes in acidity,viable bacteria and volatile flavour substances during storage,and non-targeted metabolomic assays were performed using liquid-liquid mass spectrometry to identify the differential metabolites,further screen the important differential metabolites and investigate their functional properties.The major research findings are as follows:1)Active fermented soymilk beverages prepared from soybean isolate protein powder,hydrolysed soybean protein powder and whole soybean protein powder were subjected to sensory scoring,and soybean isolate protein powder was finally selected as the raw material for the preparation of active fermented soymilk beverages and for subsequent research.The p H and titratable acidity of the PC646 group were not significantly different from those of the PC-01 group during storage at 4°C(P>0.05).At the end of storage,the number of viable bacteria in the PC646 group was significantly higher than that in the PC-01 group(P<0.05),reaching 5.2×10~8 CFU/m L,and the results of multiple light scattering showed that the active fermented soymilk beverage prepared by Lacticaseibacillus paracasei PC646 had good storage stability.2)By measuring the volatile flavour substances during storage of the two groups of active fermented soymilk beverages,a total of 148 volatile flavour substances were detected,among which the relative contents of n-pentanal,n-hexanal,benzaldehyde,2-heptenal,(E)-2-haptenal,(E,E)-2,4-decadienal,3-methylbutyraldehyde and other substances that produce bean-like flavour were gradually decreasing;there were also some aldehydes,esters,The aldehydes,esters,ketones,alcohols and other flavouring substances such as 2-heptanone,hydroxyacetone,1-nonanol,ethyl acetate,trans-2-nonenal,2,6-dimethylpyrazine,etc.brought a pleasant fruity freshness,floral and creamy aroma to the active fermented soymilk beverage,effectively reducing the beany flavour of the samples and making them soft and refreshing in taste.3)Differential metabolites of the samples were determined by untargeted metabolomics and key differential metabolites were analysed,which revealed significant differences between the PC646 and PC-01 groups during the storage period.The differential metabolites were mainly concentrated in free amino acids,glycerol lipids and nucleosides,and the differential metabolites were analysed for pathway enrichment,mainly involving metabolic pathways such as aminoacyl-t RNA biosynthesis,arginine biosynthesis,cysteine and methionine metabolism and nitrogen metabolism.In conclusion,the application of Lacticaseibacillus paracasei PC646 in active fermented soymilk beverages can give them better organoleptic properties and storage stability.This research provides a theory and data support for the development and application of Lacticaseibacillus paracasei PC646 in active fermented soymilk beverages.