κ-Casein as a source of short-chain bioactive peptides generated by Lactobacillus helveticus

Area of Science:

• Microbiology
• Biochemistry
• Food Science

Background:

• Lactic acid bacteria, including Lactobacillus helveticus, are known for their ability to produce bioactive peptides from milk proteins.
• Casein, a major milk protein, is a rich source of peptides with various physiological functions.

Purpose of the Study:

• To investigate the capacity of different Lactobacillus helveticus strains to hydrolyze casein and release short, biologically active peptides.
• To characterize the enzymatic activity and identify the types and functions of the released peptides.

Main Methods:

• Enzymatic hydrolysis of different casein fractions (κ-CN, αS2-CN, αS1-CN, β-CN) by selected Lactobacillus helveticus strains.
• Peptide sequencing analysis to identify released peptides.
• In vitro assays to evaluate the biological activities of the isolated peptides, including ACE and DPP-IV inhibition.

Main Results:

• Lactobacillus helveticus strains demonstrated varying proteolytic activities on casein fractions.
• κ-casein was the primary source of short bioactive peptides, yielding 82 peptides, while other casein fractions yielded fewer.
• The released peptides exhibited a wide range of activities, including antioxidative, opioid, hypotensive, immunomodulating, and antibacterial effects.
• A significant number of peptides inhibited angiotensin-converting enzyme (ACE) and dipeptidyl peptidase IV (DPP-IV).
• L. helveticus strain T105 showed the highest number of cleavage sites in κ-casein and produced peptides with the most significant functional activities.

Conclusions:

• Lactobacillus helveticus is a promising source for generating functional peptides from casein.
• The specific strain and casein fraction significantly influence the yield and type of bioactive peptides produced.
• The identified peptides hold potential for applications in functional foods and pharmaceuticals due to their diverse health benefits.