Optimising decolourization and nitrogen component properties of corn protein hydrolysate: impact of activated carbon dosage and pH

Summary This research was designed to examine the effects of activated carbon dosage and pH on various attributes of corn protein hydrolysate, including decolourization efficiency, nitrogen component, amino acid (AA) composition, protein secondary structure, and antioxidant activity. Optimal pigment elimination of occurred within the pH range of 2.0–4.0, utilising the hydrolysate as the control. Remarkably, the removal of trichloroacetic acid (TCA) insoluble peptide was evident at pH 4.0. The decolourization process elicited considerable reduction of the aromatic AA, exhibiting pronounced decreases of acidic AA (Glu and Asp) within the pH range of 2.0–4.0, and basic AA (His, Lys, and Arg) within the range of 6.0–8.0. Meanwhile, infrared spectroscopy analyses indicated that a dosage of 0.5% activated carbon at pH 4.0, effectively preserved the secondary structure and ratios of the control, maintaining its antioxidant activity. These results provide insights into optimisation strategies for decolourization in the food industry.