Characterization of Bioactive Peptides and ACE-Inhibitory Activity in Fermented Sheep Milk Using Indigenous Starter Cultures

Abstract

Fermented dairy products are increasingly recognized for their potential health-promoting properties, particularly due to the generation of bioactive peptides during fermentation. This study characterizes bioactive peptides and evaluates angiotensin-converting enzyme (ACE)-inhibitory activity in fermented sheep milk produced using indigenous starter cultures. Controlled fermentation trials were conducted using locally isolated microbial strains to assess their influence on proteolysis, peptide formation, and functional properties of the final product. Key parameters measured included peptide profile, degree of hydrolysis, ACE-inhibitory activity, microbial viability, and basic physicochemical properties such as pH and acidity. Results indicated that fermentation with indigenous starter cultures significantly enhanced the release of low-molecular-weight bioactive peptides with strong ACE-inhibitory activity, suggesting potential antihypertensive benefits. The extent of peptide formation varied among cultures, with certain strains demonstrating superior proteolytic activity and functional performance. Additionally, fermented products maintained desirable sensory characteristics and microbial stability, supporting their suitability for consumption. The study highlights the importance of selecting appropriate starter cultures to maximize the functional value of fermented sheep milk. While analytical techniques were used to characterize peptide profiles and bioactivity, the primary focus remains on dairy product quality and value addition. These findings provide practical insights for dairy producers to develop functional fermented products using indigenous microbial resources, enhancing the nutritional and therapeutic value of sheep milk while supporting sustainable and region-specific dairy processing practices.