不同冻结温度下牛肉的肌原纤维蛋白变性与肌肉持水性  

Myofibrillar Protein Denaturation and Water-Holding Capacity of Beef Frozen at Different Temperatures

作　　者：钱书意 李侠[2] 孙圳[2] 尚柯[2] 关文强[1] 张春晖[2] QIAN Shuyi;LI Xia;SUN Zhen;SHANG Ke;GUAN Wenqiang;ZHANG Chunhui(Tianjin Key Laboratory of Food Biotechnology,College of Biotechnology and Food Science,Tianjin University of Commerce,Tianjin 300134,China;Comprehensive Key Laboratory of Agro-products Processing,Ministry of Agriculture,Institute of Food Science and Technology,Chinese Academy of Agricultural Sciences,Beijing 100193,China)

机构地区：[1]天津商业大学生物技术与食品科学学院,天津市食品生物技术重点实验室,天津300134 [2]中国农业科学院农产品加工研究所,农业部农产品加工综合性重点实验室,北京100193

出　　处：《食品科学》2018年第15期24-30,共7页Food Science

基　　金：国家自然科学基金面上项目(31371797)。

摘　　要：为明确冷冻温度对牛肉肌原纤维蛋白变性和肌肉持水性(water-holding capacity,WHC)的影响、探讨肌原纤维蛋白变性与WHC的相关性。以牛背最长肌作实验材料,探究-9、-18、-23、-38℃下冻结后肌原纤维蛋白理化特性和牛肉WHC。通过测定巯基含量、蛋白质溶解度、Ca2+-三磷酸腺苷酶(adenosine triphosphatase,ATPase)活力及蛋白质热稳定性考察牛肉冻结后肌原纤维蛋白变性情况,利用解冻汁液流失与加压失水率指标衡量牛肉WHC,采用低场核磁共振(low field-nuclear magnetic resonance,LF-NMR)波谱和磁共振成像(magnetic resonance imaging,MRI)技术对比分析了肌肉水分分布情况,并于4℃解冻后测定了色差与剪切力。结果表明:-23℃与-38℃下冻结试样较-9℃与-18℃肌原纤维蛋白变性程度小:-23℃与-38℃下冻结试样蛋白质溶解度、Ca^(2+)-ATPase活力、巯基含量和总变性焓相比-9℃与-18℃实验组较高(P<0.05)。-23℃与-38℃下冻结牛肉解冻后L~*值、b~*值、剪切力、解冻汁液流失和加压失水率显著低于-9℃与-18℃(P<0.05)。LF-NMR及MRI结果相互佐证了肉样在-23℃与-38℃冻结下肌肉WHC高于-9℃与-18℃的实验结果。肌原纤维蛋白理化特性(蛋白质溶解度、Ca^(2+)-ATPase活力、巯基含量、总变性焓)与WHC(解冻汁液流失率、加压失水率)均呈极显著相关(P<0.01),L~*、b~*值及剪切力亦与WHC存在极显著相关(P<0.01)。相关性分析结果验证了牛肉冻结过程中肌原纤维蛋白变性对肌肉持水性存在显著影响,进而导致牛肉解冻后出现肉色劣变、嫩度下降及汁液流失。This study aimed to research the effect of freezing temperature on beef myofibrillar protein denaturation and water-holding capacity(WHC),and to explore the correlation between myofibrillar protein denaturation and WHC.Beef Longissimus dorsi frozen at?9,?18,?23 and?38℃were tested.Myofibrillar protein denaturation was investigated by the determination of sulfrydryl content,protein solubility,Ca2+-adenosine triphosphatase(ATPase)activity and protein thermal stability.WHC was evaluated by thawing loss and pressing loss.In addition,muscle water distribution was analyzed by low field nuclear magnetic resonance(LF-NMR)and magnetic resonance imaging(MRI).Color difference and shear force were also measured after thawing at 4℃.Results demonstrated that samples frozen at?23 and?38℃showed lower degree of protein denaturation,higher protein solubility,Ca2+-ATPase activity and total denaturation enthalpy than those frozen at?9 and?18℃(P<0.05).In addition,L*value,b*value and shear force in thawed samples,thawing loss and pressing loss dropped significantly compared to those frozen at?9 and?18℃(P<0.05).LF-NMR and MRI analyses consistently showed that freezing at?23 and?38℃resulted in higher WHC than at?9 and?18℃.Furthermore,the physicochemical properties(solubility,Ca2+-ATPase activity,sulfrydryl content and total denaturation enthalpy)as well as L*value,b*value and shear force of beef myofibrillar protein were highly significantly correlated with WHC(P<0.01).Consequently,myofibrillar protein denaturation during beef freezing had a significant impact on WHC,causing color deterioration,reduced tenderness and juice loss after thaw.

关 键 词：冻结温度 牛肉 肌原纤维蛋白变性 持水性 

分 类 号：TS251.1[轻工技术与工程—农产品加工及贮藏工程]