Effects of cholesterol-assimilating probiotic strains on yogurt quality, flavor, and metabolic profiles during storage.

To investigate the effects of probiotics with cholesterol-assimilating potential on yogurt quality, flavor, and metabolic characteristics, Lactiplantibacillus plantarum JHJ3-3 and Lacticaseibacillus paracasei SMN16-1 were screened and applied in yogurt fermentation. The 2 strains were co-inoculated with commercial starter cultures at initial low (1 × 106 cfu/mL) and high (1 × 109 cfu/mL) inoculation levels before fermentation. The results showed that probiotic-supplemented yogurts maintained high viable counts, reaching up to (2.47 ± 0.32) × 109 cfu/g after 21 d of storage. Compared with the Control, probiotic addition generally increased water-holding capacity (WHC), reduced syneresis, and helped maintain the stability of the microgel structure. Improvements in texture and changes in rheological profiles were also observed, particularly in the high-dose groups. JHJ3-3 exhibited stronger post-acidification ability, whereas both probiotic strains, particularly at high inoculation levels, helped maintain higher viable counts during storage. SMN16-1 was associated with the accumulation of flavor-related compounds contributing to milky, floral, and coconut-like notes. Untargeted metabolomics further revealed that high-dose supplementation (JHJ3-3 (H) and SMN16-1 (H)) was associated with changes in multiple metabolic pathways, including GABAergic synapse, butanoate metabolism, and branched-chain amino acid biosynthesis. These findings suggest that high-dose probiotic supplementation substantially altered the metabolic characteristics of yogurt during storage. Overall, this study provides a theoretical basis and technical support for the development of probiotic yogurt containing cholesterol-assimilating strains.