Preparation and in vitro digestive stability of peanut α-glucosidase inhibitory pep-tides by dual-enzyme method

To efficiently utilize peanut protein resources and investigate the hypoglycemic potential of the resulting enzymatic hydrolysates, peanut protein was extracted via alkali dissolution and acid pre-cipitation. Using the α-glucosidase inhibitory rate as the evaluation index, dual-enzyme hydrolysis conditions were optimized through response surface methodology. The results indicated that en-zymatic hydrolysates derived from Yuhua 37, a high-oleic peanut cultivar, exhibited superior α-glucosidase inhibitory activity. Sequential hydrolysis of peanut protein using alcalase followed by trypsin was carried out, and the optimal conditions were established as follows: substrate concen-tration of 1.7 g/100 mL, total enzyme dosage of 4.7% (with a 1:1 mass ratio of the two enzymes), and total hydrolysis time of 156 min (with an enzyme action time ratio of 5:1). Under these con-ditions, the α-glucosidase inhibitory rate of the resulting peanut peptides reached 68.41±0.45% at a peptide concentration of 2 mg/mL, accompanied by a degree of hydrolysis of 25.14±0.04%. Compared with single-enzyme hydrolysis in preliminary experiments, the dual-enzyme approach significantly reduced enzyme consumption while maintaining comparable inhibitory activity. Simulated in vitro gastrointestinal digestion was found to either enhance or diminish the α-glucosidase inhibitory activity of protein-derived peptides depending on their source; notably, the activity of the self-prepared peanut peptides was reduced following digestion. In conclusion, alt-hough the optimized dual-enzymatic hydrolysis process facilitates the efficient production of highly active peanut-derived α-glucosidase inhibitory peptides with lower enzyme usage, the resulting inhibitory activity is substantially diminished after in vitro simulated gastrointestinal digestion.