Different Temperature Treatments of Millet Grains Affect the Biological Activity of Protein Hydrolyzates and Peptide Fractions

The objective of this study was to analyze millet protein hydrolyzates and peptide fractions with molecular mass under 3.0 kDa obtained from grains treated with different temperature values as inhibitors of angiotensin-converting enzyme (ACE), alpha-amylase, and alpha-glucosidase activity. The protein fractions were hydrolyzed in vitro in gastrointestinal conditions and the highest degree of hydrolysis was noted for globulin 7S obtained from control grains (98.33%). All samples were characterized by a high peptide bioaccessibility index, which was 23.89 for peptides obtained from globulin 11S after treatment with 100 degrees C. The highest peptide bioavailability index was noted for peptides obtained from globulin 11S after the treatment with 65 degrees C (2.12). The highest potential metabolic syndrome inhibitory effect was determined for peptide fractions obtained from the prolamin control (IC50 for ACE and alpha-amylase was 0.42 and 0.11 mg/mL, respectively) and after the 100 degrees C treatment (IC50 for ACE and alpha-glucosidase was 0.33 and 0.12 mg/mL, respectively) and from globulin 11S after the 65 degrees C treatment (IC50 0.38 and 0.05 for ACE and alpha-glucosidase, respectively). The effect of these samples on endothelial cell HECa10 was determined. The sequences of potential inhibitory peptides were identified as GEHGGAGMGGGQFQPV, EQGFLPGPEESGR, RLARAGLAQ, YGNPVGGVGH, and GNPVGGVGHGTTGT.