Amaranth (Amaranthus spp.) grains have become essential for human health and nutrition; due to the presence of bioactive compounds that have shown some biological activities. This study aimed to evaluate the effect of germination, enzymatic hydrolysis, and its combination on the phytochemical compounds and antioxidant activity in Mexican amaranth. Germinated amaranth flours (GAF) exhibited increases in the concentrations of soluble protein (SP), total phenolic content (TPC), total flavonoid content (TFC), total anthocyanin content (TAC) and antioxidant activity (AOX) by 35.7, 17.2, 163.0, 1472.2, and 54.3%, respectively, compared with ungerminated amaranth flours (UAF). In SDS-PAGE, both hydrolysates of UAF and GAF exhibited low molecular weight bands (< 10 kDa). The hydrolysates of UAFH and GAFH had the highest degree of hydrolysis at 205 min of sequential hydrolysis (pepsin with pancreatin) time with 73.4 and 60.3%, respectively. Both hydrolysates obtained from GAF and UAF released significantly SP, TPC, TFC after sequential enzymatic hydrolysis (up 205 min), which led to a remarkable improvement of AOX when compared to nonhydrolyzed amaranth samples. The UAFH and GAFH had the best AOX at 270 min of enzymatic hydrolysis with 983.1 and 1304.9 μmol TE/mg SP, respectively. Hence, the combination of germination and enzymatic hydrolysis could be used to produce functional ingredients for food product development.
Keywords: Amaranth; Antioxidant capacity; Enzymatic hydrolysis; Germination; Phytochemicals.