Incorporation of probiotic Lacticaseibacillus paracasei into a standard yogurt starter culture can drastically improve its health promoting properties. However, besides being an advantage in itself, the incorporation of a new probiotic strain can significantly affect the overall composition of fermented milk. In this article, the effect of incorporation of the L. paracasei probiotic strains (KF1 and MA3) into several standard yogurt starter cultures (consisting of the following strains: Streptococcus thermophilus 16t and either Lactobacillus delbrueckii Lb100 or L. delbrueckii Lb200) was investigated. Such parameters as the degree of proteolysis, antioxidant activity, ACE-inhibitory activity, content of organic acids, profile of FAs and profile of volatile organic compounds were measured, and the influence of the starter culture composition on these parameters was described. It was demonstrated that, at least in the case of the studied strains, yogurt with L. paracasei had an advantage over the standard yogurt in terms of the content of acetoin, acetic acid, butyric acid and conjugated linoleic acid. Moreover, the incorporation of L. paracasei KF1 significantly improved the hypotensive properties of the resulting yogurt. Thus, the presented study provides insight into the bioactive molecules of probiotic yogurt and may be useful for both academia and industry in the development of new dairy-based functional products.
Keywords: ACE inhibition; Lacticaseibacillus paracasei; Lactobacillus delbrueckii; Streptococcus thermophilus; antioxidant activity; fatty acids; organic acids; probiotics; volatile organic compounds; yogurt.