Inhibitory effects of oat peptides on lipolysis: A physicochemical perspective

Studies on the control of lipid digestion by food-derived active substances have prioritized the direct inhibition of lipase, ignoring the influence of these substances on the stability of bile salt (BS)-stabilized oil emulsions, which are essential for the hydrolysis of triglycerides by lipase. This study aimed to demonstrate the inhibitory potential of oat peptides (OPs) on lipolysis due to lipase inhibition, in particular, the physicochemical destruction of BS-stabilized emulsions. OPs were characterized by an enterostatin-like X-Pro-Y-Pro-Arg terminal sequence, competitively and/or noncompetitively inhibited lipase, and even caused lipase conformational changes. Interestingly, OPs destabilized BS-stabilized emulsions by weakening the rheological cross-linking structure of the emulsions through competitive hydrophobic binding to BS. Further analysis revealed that the H-bond binding of OP to BS significantly destroyed the hydrophilic and lipophilic balance of BS by increasing the surface hydrophobicity. These findings provided novel insights into the action mechanism of bioactive peptides on lipid digestion.