青海省养殖三倍体虹鳟呈味核苷酸和挥发性风味物质的研究

本研究以国产虹鳟主产地-青海省龙羊峡、公伯峡和拉西瓦网箱养殖三倍体虹鳟为研究对象，采用高效液相色谱法检测分析呈味核苷酸物质，用顶空固相微萃取（headspace solid phase microextraction，HS-SPME）结合气相色谱-质谱联用（gas chromatgraph ymass spectrometry，GC-MS）分析挥发性化合物。结果显示:青海省养殖虹鳟鱼肉呈鲜味的肌苷酸含量为176~242 mg/100 g，其中，公伯峡和拉西瓦养殖虹鳟鱼肉肌苷酸含量显著高于龙羊峡产地组（P<0.05）；挥发性化合物共鉴定出69种，用气味活度值法（odor activity value，OVA）筛选出21种气味活性物质，其中壬醛、辛醛、2-壬烯醛、1-辛烯-3-醇和己醛对虹鳟鱼肉的气味贡献较大，主要呈青草味、油脂味、花香味和鱼腥味。公伯峡和拉西瓦养殖虹鳟鱼肉挥发性化合物含量整体较高。综上，青海省养殖三倍体虹鳟鱼肉呈味核苷酸含量较高，挥发性化合物种类丰富。拉西瓦和公伯峡养殖虹鳟风味相似，具有较高的肌苷酸含量和挥发性气味物质，龙羊峡养殖虹鳟新鲜度较高，鲜味及气味强度较低。研究结果可为养殖三倍体虹鳟鱼肉风味物质的分析和调控提供一定的理论依据。

Flavor Nucleotides and Volatile Flavor Compounds of Net-Cage Farmed Triploid Rainbow Trout in Qinghai Province

To investigate the flavor profile of triploid rainbow trout from Qinghai Province, high performance liquid chromatography (HPLC) and headspace solid phase microextraction (HS-SPME) combined with gas chromatography-mass spectrometry (GC-MS) were used to analyze the flavor compounds of fish cultured in net cages from Longyangxia, Gongboxia and Laxiwa. Results showed that the inosinic acid (IMP) content of farmed rainbow trout in Qinghai Province was 176~242 mg/100 g. The IMP content of rainbow trout in Gongboxia and Laxiwa was significantly higher than that in Longyangxia group (P<0.05). As for odor chemicals, a total of 69 volatile compounds were identified, 21 odor active compounds were screened by odor activity value (odor activity value, OAV) method. Nonanal, octanal, 2-nonenal, 1-octene-3-ol and hexanal contributed greatly to the typical smell of triploid rainbow trout with grassy, oily, floral and fishy characteristics. Volatile compounds content in the fillet of rainbow trout from Gongboxia and Laxiwa was relatively higher than those in Longyangxia group. In summary, triploid rainbow trout farmed in Qinghai Province obtained a high content of flavor nucleotides and was rich in volatile compounds. The rainbow trout farmed in Laxiwa and Gongboxia with high content of inosinic acid and volatile odor compounds showed similar flavor profile. Longyangxia cultured rainbow trout had high freshness, lower taste and odor intensity. The results would provide a theoretical basis for the analysis and regulation of fish flavor compounds in cultured triploid rainbow trout.