To determine the optimum conditions of simultaneous high-temperature cooking and sterilization for the production of ready-to-eat crayfish, changes in the color, pH value, texture and sensory score of crayfish were examined under different sterilization conditions, and the influence of different sterilization conditions on the quality of crayfish was analyzed. The results showed that the product quality was significantly affected by sterilization temperature and time (P < 0.05), and higher sterilization temperature and longer sterilization time had a greater impact on it. Crayfish sterilized at 110 ℃ for 10 min had significantly better springiness, hardness and chewiness (P < 0.05), and a significantly lower yellowness value (P < 0.05), and a higher sensory evaluation score compared to the other groups. The shelf life of the product was 35 days at 4 ℃.

To investigate the difference in the comprehensive quality of free amino acids (FAA) in crayfish meat from different co-culture modes, the FAA composition of crayfish tail meat from three representative co-culture modes in Xinghua city of Jiangsu province was determined, and the contribution of FAA to the taste of crayfish meat was evaluated by computing the taste active value (TAV). Comprehensive evaluation of FAA in crayfish meat was performed using principal component analysis (PCA) and cluster analysis. The results showed that 17 amino acids were found in crayfish meat from each co-culture mode, and the total amount of FAA was 21.80–27.11 mg/g. Arginine (Arg) was the most abundant FAA in all samples, accounting for 55.64%–67.76% of the total FAA, which was much more abundant than the other amino acids. Moreover, Arg contributed the most to the taste of crayfish meat. The TAV of the sweet amino acid alanine (Ala) and the bitter amino acid histidine (His) in crayfish were greater than 1 for all co-culture modes, indicating that both amino acids contributed to the taste of crayfish meat. The TAV of glutamic acid (Glu) as the amino acid with the strongest umami taste was greater than 1 only in crayfish meat from rice-crayfish mode with one-rice and two-crayfish in a field (RC2). Three principal components were extracted for the 17 amino acids, which cumulatively explained 89.937% of the total variance and could reflect the comprehensive information of amino acids in crayfish meat. The results of PCA showed that RC2 ranked first, and crayfish-crab mode (CC1) ranked last. The hierarchical cluster analysis divided crayfish meat from different co-culture modes into three categories. Similar results were obtained by PCA. This study demonstrated that the comprehensive quality of FAA in crayfish from rice-crayfish co-culture mode was better than that in crayfish from the other co-culture modes.

This study aimed to investigate the effect of frozen storage time on the flavor of cooked crayfish. Headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) was used to detect the types and contents of volatile components in the meat and hepatopancreas of crayfish during the frozen storage, and the key components causing the flavor deterioration of crayfish were identified based on odor activity values (OAV). The results showed that the electronic nose could clearly distinguish the differences in odor between crayfish with different freezing times. The contents of alcohols, aldehydes, ketones, nitrogen oxides, alkanes, and sulfides in the meat and hepatopancreas increased with storage time. After 4 months of frozen storage, the key components related to flavor deterioration in the meat were nonanal and pentanal, while those in the hepatopancreas were hexanal and nonanal. After 12 months of frozen storage, the key components related to flavor deterioration in both the meat and hepatopancreas were hexanal, heptanal, nonanal, pentanal, 1-octen-3-ol, and 2,3-octanedione. Sensory evaluation with compounding different concentrations of the key odor components revealed that the off-flavor intensity increased continuously with frozen storage time. A quantitative method for detecting the key odor components was established, which could be used to evaluate the flavor changes of cooked crayfish during the frozen storage. In summary, the flavor of cooked crayfish deteriorated during frozen storage. This study provides a reference for controlling the flavor deterioration of cooked crayfish during frozen storage.