Casein-phenol interactions occur during digestion and affect bioactive peptide and phenol bioaccessibility

Area of Science:

• Food Science
• Biochemistry
• Nutritional Science

Background:

• Casein (CN) possesses proline residues capable of binding polyphenols.
• Evidence of casein-polyphenol interaction exists in model systems, but effects during digestion remain unclear.

Purpose of the Study:

• To investigate casein-polyphenol interactions during in vitro digestion.
• To assess the impact on polyphenol bioaccessibility and bioactive peptide release.

Main Methods:

• In vitro digestion of casein or casein hydrolysate with various phenolic compounds (chlorogenic acid, ellagic acid, catechin, green tea extract, tea extract).
• Assessed total antioxidant capacity (TAC), degree of hydrolysis, and bioactive peptide formation.

Main Results:

• Co-digestion increased bioaccessible TAC (1.17-1.93 fold) due to enhanced release of antioxidant peptides.
• Higher TAC in the insoluble fraction suggests phenol transport to the colon.
• Phenol type and concentration influenced bioactive peptide release, with catechins being most effective.
• β-casomorphin formation was significantly affected by co-digestion.

Conclusions:

• Casein-polyphenol interactions occur during digestion, influencing bioactive peptide release.
• These interactions can enhance antioxidant peptide release and potentially facilitate polyphenol transport to the colon.