Application Of Electronic Nose In Freshness And Flavor Analysis Of Grass Carp

Grass carp is the best of the four major Chinese carps, which has several advantages: easy feeding, fast growing, strong adaptation and reasonable price. As a result, grass carp has an increasing sale in domestic and overseas market.In this study, freshness and flavor analysis of grass carp at the storage of 4℃ using electronic nose and GC-MS were investigated.1. Pre-detection was conducted with electronic nose. The results showed electronic nose can distinguish the odor of grass carp at different storage time. Operation parameters were optimized using response surface methodology. The best parameters were gas flow 350 mL/min, sampling time 65 s, washing time 150 s。2. The results showed 6-7 days of shelf life at 4℃ using pH, TVB-N, total bacteria count, sensory analysis while PCA and LDA were 92.9% using electronic nose which meant that it can distinguish odor of grass carp at different storage time. PLS prediction model was used to predict shelf life of grass carp at 4℃. The result had a good correlation with that of traditional methods at 6 days.3. The results showed that 48,27,28,20 volatile compounds of grass carp at 4℃ were separately analyzed using GC-MS at 1,3,5,7 days. Species and contents of these compounds led to difference of flavor of grass carp during storage which had the same result as electronic nose. Grass carp was also analyzed using electronic nose and GC-MS under different cooking methods. PCA reflected that flavor under different cooking methods was definitely different while steamed and boiled ones were similar. Therefore, cooking methods influenced compounds formation in grass carp.26,29,25,25 compounds were separately determined by GC-MS under 4 different cooking methods. Aldehydes and ketones were the most while pyrazine and furan compounds also existed. The results indicated that different volatile compounds were produced under 4 different cooking methods with electronic nose and GC-MS. Electronic nose has accuracy in grass carp flavor determination. Sensory analysis showed a highest score in steamed grass carp with a good quality.