Antioxidant Properties of Peptides Extracted from Tenebrio molitor Larvae

Abstract

The goal of this study was to identify new bioactive peptides in extracts derived from Tenebrio molitor (T. molitor) larvae for the development of functional foods. After extraction from freeze-dried T. molitor larvae with various solvents on time course, the extracts showed the highest 2,2,1-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity at 5 and 10 hr per total protein and solid contents, respectively. When the water extract was fractionated, a high methanol concentration led to a reduced level of high-molecular-weight proteins in the centrifugal supernatant, whereas increased DPPH activity in the supernatants suggests low-molecular-weight peptides may mediate antioxidant activity in the supernatant. Most of the organic solvent partitions, excluding butanol, showed similar activities in the water phases, and the organic solvent partition fraction exhibited a 28~44% decrease in activity following heat treatment, implying that some components in the fraction become unstable in the presence of heat. The addition of proteinase K to the water extract increased DPPH activity by 10~20%, suggesting that peptides, when released from total proteins, partially increase antioxidant activity. Therefore, we suggest that the antioxidants in T. molitor larval extracts make them a potential source of functional animal food.