Effects of cooking and storage on the volatile compounds of Litopenaeus vannamei

To investigate the effects of cooking and storage on the volatile compounds of white shrimp (Litopenaeus vannamei), the electronic nose (E-nose) and headspace solid phase micro-extraction gas chromatography-mass spectrometry (HS-SPME-GC-MS) were used to analyze the volatile compounds in shrimp meat. The relative odor activity value (ROAV) and sensory evaluation methods were used to evaluate flavor change of shrimp meat. The results of E-nose showed that the effects of cooked and stored treatments were highly remarkable on the volatile compounds of white shrimp. According to GC-MS analysis, 50, 68, 63, 49 and 41 volatile compounds were detected in shrimp meat with raw shrimp, cooked shrimp, cooked shrimp cooled, cooked shrimp after placing at 4 °C overnight, and twice-cooked shrimp, respectively. After twice-cooking, the key flavor substances were slightly weakened and fresh aroma also decreased slightly in the shrimp meat. However, the first cooked had little effect on shrimp flavor. The raw shrimp meat were detected nonanal and decanal, which had a significant impact on flavor. Cooked shrimp were detected nonanal, decanal, tetradecanal and others. The twice-cooked shrimp meat were detected octadecanal, and butylated hydroxytoluene, which had a greater impact on flavor. The detected types and contents of volatile compounds were reduced in the cooked shrimp after storing, but the total difference was not significant. The results showed that the types and contents of volatile compounds of the twice-cooked shrimp could be significantly increased, and the key flavor kinds and contents of L. vannamei were also significantly lower than those first cooked shrimp. The flavor difference of cooked shrimp was not significant at 4 °C for 12 h storage.