Edible insects are increasingly recognized as sustainable protein sources due to their high nutritional value and low environmental impact. However, information on the structural and functional properties of insect protein hydrolysates produced through enzymatic hydrolysis and subsequent spray drying remains limited. This study investigated structural alterations, antioxidant activity, and peptide profiles of Gryllus bimaculatus protein hydrolysates produced using Alcalase hydrolysis followed by spray drying. Hydrolysis was conducted using Alcalase concentrations ranging from 0–2% and reaction times of 30–60 min. Fourier-transform infrared (FTIR) spectroscopy revealed pronounced modifications in protein secondary structure, evidenced by broadening and shifts in the Amide I and II bands, indicative of peptide bond cleavage and unfolding. These molecular changes coincided with enhanced antioxidant activity, with the E2-T60 hydrolysate exhibiting the highest degree of hydrolysis (50.31 ± 0.05%) and DPPH and ABTS radical scavenging activities of approximately 5615.16 ± 501.12 mg ascorbic acid equivalents/g DW and 64.64 ± 0.95 mg Trolox equivalents/g DW, respectively. Based on this quantitative antioxidant performance, the E2-T60 hydrolysate was selected for peptidomic profiling. Liquid chromatography-mass spectrometry (LC-MS) identified 168 peptides, mainly derived from myosin, troponin, apolipophorin, and cuticular proteins, including dominant short sequences such as LEQTLDELEDSLER and SIVGDQPQGDPEFIK. Several short peptides enriched in hydrophobic and charged amino acids were associated with in vitro antioxidant activity. Overall, this study elucidates the structural modifications and peptide release induced by enzymatic hydrolysis and spray drying, thereby establishing a foundation for future investigations into their functionality beyond in vitro conditions.
Kwamman et al. (Thu,) studied this question.