Isolation of peptide mixtures with potential biological activities from the protein hydrolysate of Arsenura armida larval meal

Abstract This study explores using insects as a high-quality protein source rich in bioactive peptides for human nutrition. The objectives include establishing optimal conditions for peptide extraction, identifying their sequences, and assessing their potential as antioxidants and antimicrobial agents in Arsenura armida flour. The protein content in the A. armida flour extract was 54%. To obtain potential antioxidant and antimicrobial peptides, a 10:1 and 1:1 enzyme (pepsin)/substrate ratio was employed, with digestion times of 2 h (A2) and 1 h (A4), respectively. The IC 50 value for the antioxidant assay DPPH (2, 2-Difenil-1-Picrilhidrazilo ) was 22.5 μg/μL for A2. In the antioxidant in vivo assay with Caenorhabditis elegans , A2 peptides at concentrations of 0.75 μg/μL and 1.5 μg/μL exhibited a survival percentage ranging from 32.6% to 35.3%. The A4 sample demonstrated the highest antimicrobial activity, inhibiting the growth of Gram-positive bacteria ( Listeria monocytogenes and Staphylococcus aureus ) with MIC (minimum inhibitory concentration) values of 0.11 μg/mL and 0.23 μg/mL and MBC (minimum bactericidal concentration) of 0.23 μg/mL for both. Peptide analysis revealed that A2 contained peptides with identified antihypertensive (37%) and antioxidant (58%) activities, while A4 comprised peptides with antihypertensive (62%), antioxidant (31%), and antimicrobial (2%) properties. The antimicrobial peptides identified through the BIOPEP database were LFGF and FLLF. This investigation underscores the potential of A. armida peptides as valuable components in functional foods or nutraceuticals, offering health benefits beyond basic nutrition.