Comparing chemical and enzymatic bleaching of black soldier fly protein concentrate

Bleaching of black soldier fly larvae (BSFL) protein concentrates before stabilization processes like drying is crucial to enhance their aesthetic appeal and increase consumer acceptance of the final product. The aim of this study was to investigate the most effective bleaching agent for maximizing the Whiteness Index (WI) and minimising Browning index (BI) among a peroxidase enzyme, benzoyl peroxide (BP), and H 2 O 2 . Response surface methodology was employed to optimize WI and minimize the BI as the response variables for all bleaching agents. The independent variables for peroxidase enzyme bleaching were temperature, pH, and enzyme-to-substrate-ratio (E/S), while for H 2 O 2 and BP bleaching, they were temperature, pH, and bleaching agent dosage. A 0.01% (w/w) H 2 O 2 dosage was initially added to activate the enzyme during peroxidase enzyme bleaching. For peroxidase enzyme bleaching, single-variable optimization for WI was used since its model was a good fit for experimental data, and a predicted optimum WI of 48.3% was achieved at 30 °C, pH 4 and E/S = 1%. However, an increase in enzyme addition did not increase WI. For H 2 O 2 bleaching, multi-variable optimization was used to maximize WI and minimize BI, resulting in a predicted optimum WI of 43.6% at 60 °C, pH 4 and 0.05% (w/w) H 2 O 2 . BP was not effective in bleaching the concentrate. The relative error between the predicted and experimental optimum for peroxidase enzyme was 11%, while that for H 2 O 2 bleaching was 15.1%. H 2 O 2 was the most efficient bleaching agent for bleaching BSFL protein concentrates, and the best conditions were 30 °C, pH 4 and 0.01% (w/w) H 2 O 2 .