蒸制过程中鲣鱼背肉的品质及风味变化

以鲣鱼的背部肌肉为原料，通过测定其质量损失率、pH、质构特性、肌原纤维蛋白、肌浆蛋白含量、水分分布、游离氨基酸含量、挥发性风味物质以及人工感官评定分析蒸制过程中的品质和风味的变化。结果表明，蒸制过程中的质量损失率在0～6 min迅速上升后趋于稳定、pH整体呈上升趋势，硬度显示两个波峰，在蒸制8 min时的弹性达到2.20 mm，肌原纤维蛋白、肌浆蛋白含量在0～6 min内显著下降（P<0.05）后趋于稳定，不易流动水含量不断下降，自由水含量先升高后降低。呈鲜甜味的谷氨酸含量、游离氨基酸总量随蒸制时间的变化趋势相同，整体呈现先升高后降低的趋势，游离氨基酸总量在蒸制6 min和8 min时总量分别为3369.03 mg/100 g、3438.76 mg/100 g。GC-MS分析结果显示，蒸制过程中呈腥味的庚醛和壬醛的相对含量逐渐降低，且在蒸制8 min的相对含量仅为1.14%和1.69%，去腥效果最好。人工感官分析也表明蒸制8 min时的整体评分最佳。因此选用蒸制6～8 min的条件获取到的鲣鱼鱼块的品质及风味最佳。

Quality and Flavor Changes of Bonito Back Meat during Steaming

The changes of quality and flavor of bonito back meat during steaming were analyzed by mass loss rate, pH, texture, the content of myofibrillar protein and sarcoplasmic protein, moisture distribution, the content of free amino acid and volatile flavor substances and sensory evaluation. The results showed that the mass loss rate increased rapidly from 0 to 6 min and then stabilized, while the pH increased as a whole. The hardness showed two peaks. The elasticity reached 2.20 mm when steaming for 8 min, the content of myofibrillar protein and sarcoplasmic protein decreased significantly (P<0.05) from 0 to 6 min and then stabilized. The content of bound water decreased continuously, while the content of free water increased and then decreased. Overall, the content of glutamic acid and total free amino acid showed the same trend, which increased first and then decreased with steaming time. Steaming for 6 min and 8 min, the total amount of free amino acid up to 3369.03 and 3438.76 mg/100 g, respectively. The results of GC-MS (Gas Chromatography-Mass Spectrometry) showed that the relative content of heptanal and nonanal decreased gradually during the steaming process, which possessed fish flavor, and the contents of the above aldehydes were only 1.14% and 1.69% after steaming for 8 min, respectively. Moreover, sensory evaluation showed that the overall score was the highest when steaming for 8 min. Therefore, the quality and flavor of bonito pieces were the best for steaming 6~8 min.