Evaluation of aroma characteristics of Eriocheir sinensis meat as affected by environmental ammonia

Ammonia accumulation in aquaculture systems affects the sensory quality of Eriocheir sinensis , and mechanisms linking ammonia to aroma changes remain unclear. This study investigated how ammonia exposure in aquatic environments (0, 10.47, and 41.87 mg/L total ammonia-N, 48 h) alters aroma profiles of E. sinensis meat. Using HS-SPME-GC–MS and HS-GC-IMS, we identified 26 key volatile organic compounds (VOCs) defining aroma differences. Concurrently, fatty acid profiles were analyzed through GC–MS. Ammonia exposure reduced fishy (trimethylamine, 1-octen-3-ol) and meaty (methional) aromas while enhancing plant-like (phenylethyl alcohol) and nutty (2-methylbutanal) aromas in the low-concentration group; high-concentration ammonia diminished hexanal and sulfur-containing compounds, aligning with aroma evaluation trends. Further, n-3 polyunsaturated fatty acids increased after ammonia exposure, correlating with VOCs derived from lipid metabolism. These findings reveal ammonia-induced metabolic changes in flavor precursors (e.g., fatty acids) and flavor compounds (e.g., VOCs) and provide feasible insights for optimizing aquaculture practices to improve crab quality.