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.