渔光一体养殖模式对中华绒螯蟹肝胰腺和性腺气味品质的影响

Effects of the photovoltaic fishery breeding on hepatopancreas and gonad odor of Chinese mitten crab (Eriocheir sinensis)

中文关键词: 中华绒螯蟹  渔光一体养殖模式  感官评价  挥发性化合物

英文关键词: Chinese mitten crab (Eriocheir sinensis)  Photovoltaic fishery breeding mode  Sensory evaluation  Volatile compound

中文摘要:

      渔光一体养殖模式(photovoltaic fishery breeding mode, PM)是一种采用水下养殖、水上发电的新兴环保养殖模式。本研究比较了渔光一体养殖模式与普通池塘养殖模式(common pond breeding mode, CM)养殖中华绒螯蟹(Eriocheir sinensis)在基本营养成分、感官评价和气味品质等方面的差异。对雌蟹肝胰腺和性腺进行人工及电子感官评价，测定挥发性物质的含量，并对气味品质进行综合评价。结果表明，渔光一体养殖模式能提高雌蟹的性腺指数、增加粗蛋白和粗脂肪含量；PM组肝胰腺表现青草味，电子鼻的响应值最高，PM组性腺的青草味和油脂味更明显；在肝胰腺中，鉴定出44种(PM组)和33种(CM组)物质，PM组总挥发性物质的含量[(70.53±2.91) ng/g]显著高于CM组[(16.63±0.73) ng/g] (P<0.05)，是CM组的4.2倍，其中油脂味和青草味的物质含量更高；而在性腺中，鉴定出了31种(PM组)和47种(CM组)物质，PM组和CM组总挥发性物质含量分别为(68.80± 1.86) ng/g和(71.50±4.17) ng/g，并无显著差异(P>0.05)，但CM组的三甲胺为PM组的17倍，且CM组检测到含硫化合物，异味物质较多，CM组气味品质不如PM组。渔光一体养殖模式能提高肝胰腺中的青草气味和油脂气味，降低性腺中的异味物质含量，对中华绒螯蟹雌蟹的气味品质有促进作用。本研究为优化及推广渔光一体养殖模式提供了一定的理论依据。

英文摘要:

      The photovoltaic fishery breeding is a new environmentally friendly breeding method that combines pond aquaculture and photovoltaic power generation. Combining Chinese mitten crab (Eriocheir sinensis) farming with photovoltaic power generation is a new attempt to utilize resources comprehensively. However, there is no research on the effect of photovoltaic fishery breeding on the odor formation of E. sinensis. In this study, we compared the differences in basic nutrition composition, sensory evaluation, and odor quality of E. sinensis cultured in photovoltaic fishery breeding (PM) and common pond breeding (CM) environments. Two kinds of female crabs under PM or CM had their hepatopancreas and gonads evaluated by sensory analysis, as well as their tissue indices determination, proximate composition, electronic nose, and content of volatile compounds were evaluated. The flavor-active substances (odor activity value, OAV > 0.1) generated by the two breeding methods were evaluated. The results of artificial sensory evaluation and volatile compounds determination were analyzed by partial least squares (PLS) to comprehensively evaluate the odor characteristics of the hepatopancreas and gonads of Chinese mitten crab. The results of tissue indices and proximate composition showed that the gonads index of female crab was increased by the photovoltaic fishery breeding mode (P<0.05). The crude protein and crude fat contents in the PM group were significantly higher than those in the CM group (P<0.05). The photovoltaic fishery breeding mode can promote the E. sinensis growth. The sensory evaluation showed that the hepatopancreas grassy and fatty taste scores in the PM group were higher than those in the CM group. The hepatopancreas' electronic nose response value in the PM group was the highest, and the gonads' grassy odor in the PM group was more noticeable. The principal component analysis (PCA) of the electronic nose showed that the two breeding methods had a significant effect on the hepatopancreas odor profile of female crabs. The determination of volatile compounds by GC-MS showed a total of 44 (PM group) and 33 (CM group) substances identified in the hepatopancreas, mainly including aldehydes (22.59% and 21.83%), alcohols (21.79% and 28.14%), and alkanes (37.03% and 38.00%). In the gonads, 31 (PM group) and 47 (CM group) substances were identified, mostly aldehydes (13.01% and 31.19%), aromatic (7.54% and 3.99%), alcohols (8.18% and 9.69%), and alkanes (67.49% and 44.20%). Twenty-two hexanal-related substances were detected simultaneously in the hepatopancreas and gonads of female crab, while fourteen 2-methyl-2-butenal-like substances were detected only in the hepatopancreas, and fourteen 2-pentenal-like substances were detected only in the gonads. In the hepatopancreas, the total volatiles content in the PM group [(70.53±2.91) ng/g] was significantly higher than that in the CM group [(16.63±0.73) ng/g] (P<0.05), corresponding to 4.2 times more total volatiles in the PM group than in the CM group. Among these, the contents of fatty and grassy flavor substances such as 2-methyl-butenal, 2-methyl-2-butenal, 4-heptenal, 3,5-3,5-octadien-2-one, and 1-octen-3-ol in the PM group were higher than in the CM group (P<0.05). In gonads, the total volatiles content in the PM and CM groups were (68.80±1.86) ng/g and (71.50±4.17) ng/g, respectively, showing no significant difference between the two groups (P>0.05). Nonetheless, the PM group's 2-ethylfuran and D-limonene contents were significantly higher than those in the CM group (P<0.05). The grassy odor in the PM group was stronger in relation to the CM group, and the trimethylamine content in the CM group was 17 times higher than that in the PM group. Sulfur-containing compounds (dimethyl disulfide and thiophene) were detected in the CM group, and the odorous substances in this group were more abundant than those of the PM group, reflecting the inferior odor quality of the CM group. Several different flavor active substances were detected in hepatopancreas (11) and gonads (10) of female crabs under the two breeding methods, respectively. In the hepatopancreas, the OAV of (E)-2-octenal, octenal, (E)-2-nonenal, nonanal, decanal, and 2-pentylpyridine of the PM group was greater than 1, while the CM group's OAV of only (E)-2-nonenal and nonanal was greater than 1. The OAV of (E)-2-nonenal and nonanal was greater than 1 in gonads of the PM group. In the CM gonads, the OAV of hexanal, nonanal, and decanal was greater than 1. Overall, the OAV content was higher than 1 in the hepatopancreas in the PM group, which was higher than that in the CM group. In the gonads, the OAV content was greater than 1 for the CM group, revealing a fishy and ammoniacal odor that resulted in an overall unpleasant odor. PLS analysis showed a strong correlation between the PM group and grassy and fishy odor. The volatiles associated with hepatopancreas in the PM group were octanal, (E)-2-octenal, 2-decanone, 1-octen-3-ol, 2-pentyl furan, among others, while few volatiles associated with hepatopancreas were found in the CM group. Compounds strongly correlated with the CM group gonads included nonanal, hexanal, and other fishy odor aldehydes, trimethylamine, and 2-ethylfuran. The gonads' odor in the CM group was higher than in the PM group. The photovoltaic fishery breeding method can improve the grassy and fatty odors in the hepatopancreas, reduce the content of odor substances in the gonads, and promote the odor quality of female E. sinensis. This study provides a theoretical basis for optimizing and popularizing the photovoltaic fishery breeding method.