The activity of starter cultures is one of the most important factors that determine the fermentation process and sensory characteristics of yoghurt. During the past decades, societal interest in healthy foods has contributed to the development of functional yoghurt variants incorporated by health-promoting bacteria called “probiotics”.
Compared to traditional yoghurt starters, there is still limited information regarding the metabolic activity of probiotics in milk. Therefore, the main objective of this research was to investigate the simultaneous growth and metabolite production by yoghurt starters and probiotics during set-yoghurt fermentation and refrigerated storage.
Impact of probiotics on molecular yoghurt profile
Since many probiotic strains are not able to survive well in yoghurt, a strategy to enhance their survival was additionally applied by preculturing of probiotics under sublethal stress conditions prior to inoculation in milk. The microbial activity during fermentation and storage was investigated by monitoring bacterial population dynamics, milk acidification and changes in volatile and non-volatile metabolite profiles of yoghurt.
This research provides new information regarding the impact of probiotics on the molecular profile of yoghurt and potential application of stress-adapted probiotics in an actual food-carrier environment.