Differences in Aroma Metabolite Profile, Microstructure, and Rheological Properties of Fermented Milk Using Different Cultures

Texture and flavour are the key attributes determining sensory quality and are highly affected by starter cultures. A selection of phenotypic strains is needed to create diverse texture and flavour to meet consumers' preferences. In this study, the use of five lactic acid bacteria strains in the production of fermented milk, along with the metabolite profiles, microstructure, and rheological properties of the fermented milk samples, was investigated. Our results showed that Lactobacillus helveticus (LH) and Streptococcus thermophilus (ST) had a stronger acidification during fermentation but resulted in products with a coarser protein network compared to Lactococcus lactis (BL1) and Leuconostoc mesenteroides (CL3). Milk fermented by LH had the highest viscosity and exopolysaccharide concentration, while milk fermented by ST had the highest concentration of diacetyl. Although Leuconostoc pseudomesenteroides (CL3ST) had a minimal acidification capability, it produced high levels of ethyl-derived compounds associated with sweet, fruity, and floral fragrances. The results demonstrated that LH and ST could be used as starter cultures targeting fermented milks with different viscosities, while BL1, CL3, and CL3ST are suitable as adjunct cultures to impact different acidic sharpness and flavour notes.

Automated summary

Texture and flavour, which are crucial attributes for sensory quality, are greatly influenced by starter cultures. Different phenotypic strains are required to create diverse texture and flavour in fermented milk to meet consumer preferences. This study investigated the use of five lactic acid bacteria strains in fermented milk production, looking at metabolite profiles, microstructure, and rheological properties. LH and ST showed stronger acidification but resulted in coarser protein networks compared to BL1 and CL3. LH had the highest viscosity and exopolysaccharide concentration, while ST had the highest concentration of diacetyl. CL3ST had minimal acidification capability but produced high levels of ethyl-derived compounds associated with sweet, fruity, and floral fragrances. LH and ST can be used as starter cultures for fermented milks with different viscosities, while BL1, CL3, and CL3ST are suitable as adjunct cultures for different acidic sharpness and flavour notes.