# Flavor Differences of Edible Parts of Grass Carp between Jingpo Lake and Commercial Market
## 3 Results and Discussion
### Volatile Compounds
[PERSON] et al. [24], who identified 56 and 55 volatile compounds in the grass carp's back and abdomen parts, respectively, with the main volatile compounds being alcohols, which were more abundant in the dorsum than in the abdomen. The content of 1-nonanol in CA and CB was higher. JA contained a small amount of this organic compound; none was detected in JB, and the difference between JA and CA was significant (\(p<0.05\)). This straight-chain fatty acid alcohol has a dusty and greasy odor [25] and was previously found in mussels (_Mytilus galloprovincialis_ Lmk.) [26]. [PERSON] et al. [27] also found 1-nonanol when studying the flavor of triploid common carp. Compound (\(R\))-2,4-dihydroxy-\(N\)-(3-hydroxypropyl)-3,3-dimethylbutyrate was found in JB only. It is the precursor of vitamin B5 and has a slight special smell. The alcohol most detected in the grass carp samples was 1-hexanol. It was found at greater concentrations in JA, CA, JB, and CB than in JT and CT (\(p<0.05\)), and CB contained more than that found in JB, but there were no significant differences among JA, CA, JB, and CB (\(p>0.05\)). It has a fruity and fragrant aroma. The lipid oxidation pathway contributes to the formation of linear alcohols, which may be why the 1-hexanol content of JPGC was lower than that in CGC. The 1-octanol content of JB was higher than that in CB (\(p<0.05\)). This alcohol is commonly found in aquatic products and provides a dry, sweet, sharp, fatty, waxy aroma with citrus-, orange peel-, and rose-like aromas [28]. Aldehydes have a very low odor threshold and contribute significantly to the overall flavor level of foods [29]. The total aldehyde content of JT was significantly higher than that of the other parts (\(p<0.05\)). The aldehydes detected in the grass carp samples mainly included 2,5-dihydroxybenzaldehyde, 1-nonanal, and 3-methylbutanal. The 1-nonanal contents of JA, JB, and JT were higher than those in CA, CB, and CT (\(p<0.05\)), but there were no significant differences between JA and JB (\(p>0.05\)). This aldehyde may be derived from the oxidation of unsaturated fatty acids [30] and can provide fatty, citrus, and green aromas [31]. It also emits a strong aromatic odor, which can mask other odors at low concentrations [32]. The 2,5-dihydroxybenzaldehyde contents of JT, CA, CB, and CT were higher than those in JA and JB (\(p<0.05\)), and there were no significant differences among CA, CB, and CT (\(p>0.05\)). This natural antimicrobial agent inhibits the growth of _Mycobacterium avium_ subsp. The contents of 3-methylbutanal in JA, JB, and JT were higher than those in CA, CB, and CT (\(p<0.05\)). It is a Strecker aldehyde derived from Leu and described as having peach-like, chocolate, and malty flavors [33]. It may have formed during the SPME process. Hexanal was detected in JT only. It has been reported to cause fishy or green leafy odors in aquatic products [34]. Vanillin has a vanilla aroma and has been reported to be the most potent aldehyde in aquatic products [35]. This aldehyde was detected in JA and JB in our study. Isovanillin was detected in both CB and JT, but with significantly higher levels in the latter (\(p<0.05\)). As an aroma ingredient, it is quite distinct from vanillin. Its fragrance can change with a change in the ambient temperature. Among these detected aldehydes, 2-dodecenal had a promoting effect on the fishy smell, and it was present in JT at significantly lower concentrations than in CT. The only three ketones detected in this study were xanthoxylin, 5-decanone, and 5,5-dichloro-4-spirohexanone. They were found exclusively in all three parts of CGC. [PERSON] et al. [24] also detected relatively low levels and types of ketones in grass carp. The total ester contents in JT, JB, and CB were significantly higher than those in JA, CA, and CT (\(p<0.05\)), and there were no significant differences between JB and CB (\(p>0.05\)).