Involvement of Post-digestion ‘Hydrophobic’ Peptides in Plasma Cholesterol-lowering Effect of Dietary Plant Proteins

Abstract

Peptides remaining or appearing during protein digestion were examined for a possibility of their involvement in the regulation of cholesterol levels in plasma. Plant proteins were somewhat inferior in digestibility to casein and their digestive products were abundant in ‘hydrophobic’ peptides relative to casein. The ‘hydrophobic’ peptides bound well to bile acid. There was a correlation between the plasma cholesterol level in rats given various food proteins and the hydrophobicity of their digestive products (peptic-pancreatic digests). The preponderance of hydrophobicity seems to favor an explanation for the cholesterol-lowering effects of plant proteins such as soy protein isolate and wheat gluten.