ANTIOXIDANT ACTIVITY AND TOTAL POLYPHENOL CONTENT OF INSECTS USED AS FEED AND FOOD

Abstract

This study aimed to evaluate the antioxidant activity, total polyphenol content (TPC), and correlation between TPC and antioxidant activity of eight insect species allowed as feed and three of them as food in the European Union. The DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging assay was used to measure antioxidant activity, and the Folin-Ciocalteu method was used to measure TPC. The results showed significant variability in both antioxidant activity and TPC among the tested insect species. Bombyx mori (1.64±0.01 mg TEAC/g DM; TEAC- Trolox equivalent antioxidant capacity, DM-dry matter) among all tested insects and Acheta domesticus (1.30±0.14 mg TEAC/g DM) among the insects allowed as food exhibited the highest (p<0.05) antioxidant potential, which may be attributed to their polyphenol content. On the other hand, the Hermetia illucens sample had the lowest (p<0.05) antioxidant activity (0.20±0.01 mg TEAC/g DM). The highest (p<0.05) TPC was observed in the sample of Gryllus assimilis (14.51±0.94 mg GAE/g DM; GAE- gallic acid equivalent) among the tested samples, except for the B. mori sample (13.39±0.35 mg GAE/g). Significantly (p<0.05), the lowest TPC was in the H. illucens sample (5.18±0.06 mg GAE/g DM). Mean antioxidant activity and TPC were determined to be 0.87 mg TEAC/g DM and 10.63 mg GAE/g DM, respectively. Evaluating insects grouped by their development stages (adults, larvae, pupae), pupae had the highest (p<0.05) antioxidant activity (1.64 mg TEAC/g DM), and the lowest (p<0.05) TPC was in the larvae group (8.23 mg GAE/g DM). A moderate positive correlation (r=0.625, p<0.01) was observed between TPC and antioxidant activity. The results confirmed that insects may serve as significant sources of natural antioxidants. Also, the total polyphenol content and antioxidant activity were influenced by the developmental stage.