Characterization of Antioxidant Activity of Protaetia brevitarsis seulensis Larvae

This study investigated the effects of four different processing methods—oven-drying (POD), roasting (PRD), pan-frying (PPD), and freeze-drying (PFD)—on the total phenolic content (TPC) and antioxidant activities of Protaetia brevitarsis seulensis larvae (PBL). While PFD exhibited the highest TPC (5.10 g/100 g), it showed the lowest antioxidant activities in terms of DPPH radical scavenging activity, reducing power, and iron chelating ability. Conversely, thermal processing methods, particularly PRD and PPD, demonstrated significantly superior antioxidant potential despite lower TPC values. Pearson’s correlation analysis using the treatment × concentration dataset (n = 16) indicated a strong negative correlation (r = -0.97) between TPC and DPPH radical scavenging activity; this pattern suggests that non-phenolic, heat-derived constituents (e.g., Maillard reaction-related products) and/or other reducing components may contribute to the enhanced antioxidant responses of heat-treated PBL. Principal component analysis (PCA) clearly distinguished the physicochemical characteristics of the heat-treated groups from the freeze-dried group, confirming that thermal stress induces a positive shift in antioxidant functionality. Furthermore, the Antioxidant composite index (ACI) was calculated to comprehensively evaluate the efficacy of each method; the PRD treatment achieved the highest score of 99.43, followed by PPD (96.29), POD (92.99), and PFD (78.48). These findings indicate that roasting is the optimal processing method for maximizing the antioxidant bioactivity of PBL, offering a more effective strategy for the development of functional food ingredients than conventional freeze-drying.