Production of Peptides Inhibiting Angiotensin I-Converting Enzyme and Dipeptidyl Peptidase IV through Lactic Fermentation of Amaranth Grain Proteins

This study evaluated the production of antihypertensive and antidiabetic peptides through the fermentation of amaranth grain proteins with Weizmannia coagulans. After 15 h of fermentation with W. coagulans, the initial protein content decreased by 21.57% for albumin (ALB) and 28.43% for globulin (GLOB). The electrophoretic profiles revealed progressive degradation of ALB and GLOB with increasing fermentation time. Consequently, the fermentation process generated peptides with inhibitory activity against both angiotensin I-converting enzyme (ACE) and dipeptidyl peptidase IV (DPP-IV). Gel filtration chromatography identified peptide fractions ranging from 0.95 to 5.15 kDa, notably the 0.95 kDa peptide fraction derived from GLOB, which exhibited the highest inhibitory activity against ACE and DPP-IV, with IC50 values of 0.12 and 0.27 mg/mL, respectively. Therefore, our findings show that fermentation with W. coagulans promotes the proteolysis of ALB and GLOB in amaranth grain, producing high-value peptides that can serve as bioactive ingredients in the development of nutraceuticals and/or functional foods.