Dairy yeasts produce milk protein-derived antihypertensive hydrolysates

Abstract

The potential of 20 dairy yeast strains belonging to Debaryomyces hansenii, Kluyveromyces lactis and Kluyveromyces marxianus species was examined for the production of milk protein-derived antihypertensive hydrolysates. For this purpose yeast strains were grown in microbiological medium with casein or lactoferrin as sole nitrogen source, and the inhibitory effects of casein and lactoferrin hydrolysates (CSHs and LFHs) on angiotensin I-converting enzyme (ACE) activity were determined. Based on the ACE-inhibitory activity, four CSHs and five LFHs were selected, and permeate fractions with molecular masses lower than 3kDa (pCSHs and pLFHs) were obtained. In vitro ACE-inhibitory potencies (IC50) of permeates varied from 18.8 to 87.6μg/ml (pCSHs) and from 50.2 to 500μg/ml (pLFHs). K. marxianus Km2 strain grown on either casein or lactoferrin produced the most potent permeates. pCSHs and pLFHs were orally administered to spontaneously hypertensive rats (SHRs) and exerted in vivo antihypertensive effect. In conclusion, the present study contributes to a better insight into bioactive compounds produced by dairy yeasts and shows the feasibility of selected yeasts to produce orally effective antihypertensive milk protein-derived hydrolysates.