不同冻结方式对草鱼肉挥发性成分的影响

为探明冻结方式对草鱼肉挥发性风味物质的影响,以草鱼背肉和红肉为研究对象,采用新型材料MonoTrap作为固相萃取整体捕集剂,通过电子鼻和气相色谱-质谱联用技术对经过速冻、酒精浸渍冻结和冰柜直接冻结的草鱼背肉和红肉的挥发性风味成分进行分析和鉴定。结果显示,电子鼻可以良好区分新鲜和不同冻结方式处理草鱼背肉和红肉气味,主成分分析显示冰柜直接冻结样品的气味与新鲜样品的气味差异最大。通过气相色谱-质谱检测新鲜、速冻、酒精浸渍冻结及冰柜直接冻结草鱼背肉和红肉,从背肉中分别鉴定出45、33、28种和22种挥发性物质,红肉中分别鉴定出49、38、33种和25种挥发性物质,以醛类和醇类物质为主。结果表明,戊醛、己醛、庚醛、辛醛、2-辛烯醛、壬醛、2-壬烯醛、癸醛、2-癸烯醛、十一醛、2,4-癸二烯醛、己醇、2-辛烯醇、1-辛烯-3-醇、二甲苯等化合物对草鱼肉总体风味形成有重要贡献。3种冻结方式中与新鲜样品挥发性物质的种类和相对含量最接近的是速冻后的样品,差异最大是冰柜直接冻结样品。速冻更有利于保持冻结草鱼肉的品质,冻结后草鱼肉的风味接近于新鲜鱼肉。

Effects of Different Freezing Methods on the Volatile Components of Grass Carp Meat

In order to investigate the effect of freezing methods on the volatile flavor of grass carp meat, three different freezing methods, namely quick freezing, ethanol immersion freezing and refrigerator freezing, were used to pretreat the fresh dorsal meat and red meat of grass carp. A new type of material (MonoTrap) was applied as a solid phase extraction (SPE) stationary phase to extract the volatile compounds of fish meat. The volatile flavor components were analyzed and identified by electronic nose and gas chromatography-mass spectrometry (GC-MS). The odors of fresh and frozen grass carp meat could be clearly discriminated by electronic nose. Principal component analysis (PCA) showed that the differences in odor components between ordinary refrigerator freezing and fresh meat was maximum. By GC-MS analysis, 45, 33, 28 and 22 volatile compounds were identified in fresh, quick-frozen, ethanol immersion frozen and refrigerator frozen dorsal meat, respectively, and 49, 38, 33 and 25 volatile compounds were detected in fresh, quick-frozen, ethanol immersion frozen and refrigerator frozen red meat, respectively. The main volatile compounds were aldehydes and alcohols. Also, this study demonstrated that pentanal, hexanal, heptanal, octanal, 2-octenal, nonanal, 2-nonenal, decanal, 2-decenal, undecanal, 2,4-decadienal, hexanol, 2-octen-1-ol, 1-octen-3-ol, and xylene made an important contribution to the overall flavor of grass carp meat. In terms of the type and amount of volatile components, fresh fish meat was similar to the quick-frozen sample but dissimilar to the refrigerator frozen sample. Conclusively, quick freezing was more beneficial to maintaining the quality of grass carp meat, and the flavor of frozen fish meat was similar to that of fresh fish.