Multilayered characterization of sour cream fermentation: Effects of cream origin and fermentation time on microbiota, lipid transformation, and aroma compounds

This study investigated how cream origin and fermentation time impact sour cream flavor by integrating microbial dynamics, fatty acid profiles, and volatile formation under pilot-scale conditions. Korean sour cream (KRS; produced from in-house cream) and Italian sour cream (ITS; produced from frozen cream) samples were fermented with Lactobacillus delbrueckii and Streptococcus thermophilus for 24 h. KRS exhibited greater lipid degradation, with palmitic acid decreasing by 7.8 %, and showed more dynamic volatile shifts, particularly at 12–18 h. Ethanol increased 1.35-fold and butanoic acid was 2.2-fold higher in KRS than in ITS. In contrast, ITS generated higher levels of sweeter volatiles, particularly 2-methyl-1-butanol, which was 7.6-fold higher than in KRS. L. delbrueckii was associated with late-stage, lipid-derived volatiles, and S. thermophilus was associated with early-stage compounds. Associations between fatty acids and volatiles suggested lipid metabolism contributes to flavor. These results guide cream selection and fermentation control to achieve consistent sour cream flavor.