食品科学 ›› 2021, Vol. 42 ›› Issue (7): 240-246.doi: 10.7506/spkx1002-6630-20200316-254

• 包装贮运 • 上一篇    下一篇

冻融循环对大目金枪鱼质构与蛋白质特性变化的影响

蓝蔚青,孙雨晴,肖蕾,梅俊,谢晶   

  1. (1.上海海洋大学食品学院,上海 201306;2.上海水产品加工及贮藏工程技术研究中心,上海 201306;3.食品科学与工程国家级实验教学示范中心(上海海洋大学),上海 201306)
  • 出版日期:2021-04-15 发布日期:2021-05-17
  • 基金资助:
    “十三五”国家重点研发计划重点专项(2019YFD0901604);上海市科委科技创新行动计划项目(19DZ1207503); 上海水产品加工及贮藏工程技术研究中心能力提升项目(19DZ2284000)

Effects of Freeze-Thaw Cycles on Texture Properties and Protein Properties in Big-Eye Tuna (Thunnus obesus)

LAN Weiqing, SUN Yuqing, XIAO Lei, MEI Jun, XIE Jing   

  1. (1. College of Food Sciences and Technology, Shanghai Ocean University, Shanghai 201306, China; 2. Shanghai Aquatic Products Processing and Storage Engineering Technology Research Center, Shanghai 201306, China; 3. National Experimental Teaching Demonstration Center for Food Science and Engineering (Shanghai Ocean University), Shanghai 201306, China)
  • Online:2021-04-15 Published:2021-05-17

摘要: 为研究冻融循环对大目金枪鱼质构与蛋白质特性变化的影响,实验模拟了大目金枪鱼两种温度波动条件下的反复冻融过程(超市冻融处理组F1与家庭冻融处理组F2),分别经过5 次反复冻融,测定两组样品冻融期间的理化指标(汁液流失率、高铁肌红蛋白相对含量、肌原纤维蛋白含量、总巯基含量与Ca2+-ATPase活力)及质构特性,同时结合十二烷基硫酸钠-聚丙烯酰胺凝胶电泳(sodium dodecyl sulfate-polyacrylamide gel electrophoresis,SDS-PAGE)、低场核磁共振(low-field nuclear magnetic resonance,LF-NMR)与核磁共振成像(magnetic resonance imaging,MRI)技术对比分析大目金枪鱼在反复冻融期间的品质变化。结果表明:随着冻融循环次数的增加,F1和F2组的大目金枪鱼肉质构特性均发生变化,解冻汁液流失率升高,鱼肉硬度、弹性与咀嚼性显著下降(P<0.05),黏性明显上升,鱼肉肌原纤维蛋白含量降低,总巯基含量与Ca2+-ATPase活力下降,高铁肌红蛋白含量升高。其中,在冻融循环次数相同时,F1组样品的汁液流失率高于F2组,其在第4次冻融时达到最大值,硬度也在此时明显下降;F1组样品的高铁肌红蛋白相对含量增幅、肌原纤维蛋白含量与Ca2+-ATPase活力降幅均小于F2组;SDS-PAGE结果显示冻融循环会导致部分肌肉蛋白降解,冻融循环次数的增加和冻藏温度的升高都会加快蛋白质降解速率。LF-NMR分析得出,反复冻融过程会使存在于鱼肉肌原纤维中的不可移动水转变为自由水流出,F1组样品随冻融循环次数增加自由水相对含量呈增加趋势,汁液流失率也增加,与MRI分析结果相一致。由此可见,与F2组相比,F1组冻融处理虽能抑制高铁肌红蛋白含量的升高,保持Ca2+-ATPase活力,但会导致大目金枪鱼的汁液流失率升高,质构特性变差。冻融循环次数增加会加剧鱼肉组织及蛋白质功能劣变,应尽量减少大目金枪鱼流通期间的冻融循环次数。

关键词: 大目金枪鱼;冻融循环;质构特性;蛋白质特性

Abstract: In order to explore the effects of freeze-thaw cycles on texture properties, microstructure and protein properties in big-eye tuna (Thunnus obesus), fish samples were subjected to 1-5 freeze-thaw cycles under conditions simulating temperature fluctuations encountered in a supermarket (F1) and those encountered in a household (F2). Changes in physicochemical indexes (thaw drip loss rate, metmyoglobin content, myofibrillar protein content, total sulfhydryl content and Ca2+-ATPase activity) and texture profile analysis (TPA) parameters were measured during freeze-thaw cycles. Quality changes were characterized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), low-field nuclear magnetic resonance (LF-NMR) and magnetic resonance imaging (MRI). The results showed that with increasing freeze-thaw cycles, thaw drip loss rate was increased in both groups, hardness, chewiness and springiness were significantly decreased (P < 0.05), and adhesiveness was increased; myofibrillar protein content, total sulfhydryl content and Ca2+-ATPase activity were decreased, and metmyoglobin content were increased. The thaw drip loss rate in group F1 was higher than that in group F2 at the same freeze-thaw cycles, which reached the maximum value after the fourth freeze-thaw cycle, accompanied by a significant decrease in hardness. A slower increase in metmyoglobin content, and slower decreases in myofibrillar protein content and Ca2+-ATPase activity in group F1 were observed compared with group F2. The results of SDS-PAGE showed that repeated freeze-thaw cycles caused partial protein degradation. The degradation rate was accelerated with increasing number of freeze-thaw cycles and freezing temperature. The results of LF-NMR revealed that repeated freeze-thaw cycles could result in the conversion of immobile water in fish myofibrils into free water. The relative content of free water as well as thaw drip loss rate in group F1 was increased with increasing freeze-thaw cycles, which was consistent with the results of MRI analysis. Accordingly, compared with F2, F1 was more effective in inhibiting the increase in metmyoglobin content and maintaining Ca2+-ATPase activity despite increasing thaw drip loss rate and deteriorating texture properties. Increase the number of freeze-thaw cycles could aggravate the deterioration of functional characteristics in fish tissues and proteins, leading us to conclude that the number of freeze-thaw cycles during circulation should be as small as possible.

Key words: big-eye tuna; freeze-thaw cycles; texture propertites; protein properties

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