Determination of heterocyclic aromatic amine content of protein extracts and protein hydrolysates obtained from meat trimming wastes under different process conditions

This study aimed to evaluate the formation of heterocyclic aromatic amines (HAAs) in protein extracts, non-fractionated protein hydrolysates, and < 3 kDa fractionated protein hydrolysates produced from meat trimming waste under acidic (pH 2.5) and alkaline (pH 11) extraction conditions. The novelty of this work lies in demonstrating whether HAAs occur across all major stages of meat-derived protein hydrolysate production-namely extraction, enzymatic hydrolysis, and ultrafiltration-as their formation has not been previously investigated in any stage of the production process. In total, nine HAAs were monitored, of which IQx, IQ, and MeIQx were consistently detected in all samples, while MeIQ, 7,8-DiMeIQx, 4,8-DiMeIQx, PhIP, A alpha C, and MeA alpha C were detected at variable levels. Extraction pH had a significant effect on total HAA content (P < 0.01), with the highest concentration observed in non-fractionated hydrolysates prepared following extraction at pH 2.5 (an average of 18.19 ng/g). Although individual HAA profiles varied between processing steps, the overall impact of processing on total HAA levels remained limited (P > 0.05). These findings demonstrate that extraction pH plays a decisive role in HAA formation during protein hydrolysate production and underscore the need to optimize extraction and hydrolysis parameters to ensure the safe valorization of meat trimming waste for food applications.