Synthesis of Antioxidant Peptides from Melinjo (Gnetum gnemon) Seed Protein Isolated Using Sol-Gel Immobilized Alcalase

Abstract

The synthetic of antioxidant peptides from melinjo (Gnetum gnemon) seed protein isolated using sol-gel immobilized alcalase was studied, a commercial alcalase was physically entrapped in sol-gel matrices system. Characteristics of protein hydrolyzed were evaluated by the degree of hydrolysis obtained (DH) and the peptide profile by FPLC and SDS-PAGE. The antioxidant activity of protein hydrolyzed was determined using ABTS cation, DPPH, and superoxide radical scavenging assays. The DH values increased very quickly during the second hour followed by a slow increase up to 12 hours. Melinjo seed protein isolated was hydrolyzed about 23% of degree hydrolysis at 50°C after 2 hours of incubation. Similar results were also obtained by FPLC and SDS-PAGE, the peptide profile indicated the sol-gel immobilized alcalase was produced of peptides with low molecular weight from melinjo seed protein isolated. Immobilized alcalase preserved the initial activity over 4 cycles of repeated use in a routine reaction. The ABTS assay, the hydrolysate presented a more than  5 times greater activity than non-hydrolyzed melinjo seed protein isolated. It's confirming the potential use of sol-gel immobilized alcalase in synthetic antioxidant peptides from melinjo seed protein isolated.