Abstract:The difference between the volatile components in the muscles of grass carp fed with spearmint stems and leaves and the control grass carp was distinguished. In this experiment, fresh spearmint (Mentha spicata L.) stems and leaves in the fish-flower (mint) symbiosis closed-loop system were fed to grass carp at 10% of the fish body mass together with the conventional feed. The fingerprint and qualitative analysis of volatile organic compounds of grass carp fed with spearmint and peppermint and control grass carp were conducted using gas chromatography-ion mobility spectrometry technology. 129 kinds of VOCs could be detected in the stems and leaves of spearmint, and 30 kinds identified VOCs were mainly alcohols, ketones and aldehydes. Among them, the content of the leaves was relatively high. 83 kinds of VOCs were detected in mint feeding and control grass carp, and 45 kinds of VOCs could be qualitatively identified. From the fingerprint and qualitative analysis, it was found that the contents of dipentene, phenethyl alcohol and linalool in mint feeding grass carp were higher than those of the control. The contents of odorous o-cresol, seawater and fishy trans-2-pentenal were greatly reduced. Moreover, linalool and isovaleraldehyde in 6 kinds of VOCs were detected in peppermint and significantly transferred to the feeding grass carp, which greatly reduced the original ethyl 2-methylbutyrate and 2-ethylfuran content in the control grass carp. It was further confirmed by principal component analysis that the VOCs difference between the mint feeding and the control grass carp was significant, and could be grouped into one category. The content of VOCs in the leaves of spearmint was much higher than that in the stems. The content of VOCs in the grass carp fed with mint was much higher than that in the control grass carp. The transfer of linalool with woody and floral characteristics and isovaleraldehyde with the characteristics of apple and peach flavor to the grass carp fed with mint was observed and their contents increased, which reduced some fishy smell substances affected the flavor of grass carp such as o-cresol and trans-2-pentenal. It could provide a theoretical basis for the scientific and directional utilization of medicinal and edible plants of mint and the improvement of volatile flavor substances of aquatic products.
