钙蛋白酶系统与肌肉嫩度的关系

钙蛋白酶系统主要由钙蛋白酶(μ-calpain,m-calpain)及钙蛋白酶抑制蛋白(calpastatin)组成,calpain是存在于细胞质中的依赖于Ca2+的中性蛋白酶,calpastatin是钙蛋白酶的内源抑制蛋白。本文综述了钙蛋白酶系统各种酶的结构、作用、活性调节机能及其与肉质嫩度的关系。     

内源蛋白酶在肉嫩化中的作用(综述)

本文阐述了与肉成熟有关的两类蛋白酶,即钙激活蛋白酶和溶酶体组织蛋白酶,并分别就两类酶的分类、影响酶活性的因素、在肉嫩化中的作用、分离提纯及活性测定方法等作了介绍.     

畜禽宰后肌肉嫩化相关酶研究进展

目前普遍认为参与宰后肌肉嫩化的相关蛋白酶主要有溶酶体组织蛋白酶、蛋白酶体、钙激活蛋白酶、钙激活酶抑制蛋白和半胱天冬酶5 种,然而对于成熟过程中肉的嫩化程度及机理颇具有争议。大量的研究表明,上述5 种嫩化酶在参与肉嫩化过程中其自身生理生化特性在宰后也发生变化。本文综述5 种参与宰后肉嫩化酶的分子质量、存在部位、作用底物、作用位点、激活条件、最适pH值以及对其活性具有一定影响的抑制剂,并就其影响宰后肉嫩度的作用机理及其自身状态的变化进行分析与阐述,旨在为后续研究嫩化酶在宰后改善肉嫩度方面的应用条件提供参考。     

钙蛋白酶系统磷酸化对肉嫩度的影响研究进展

嫩度是肉品食用品质中最重要的品质特性之一,钙蛋白酶系统在宰后成熟过程中对改善肌肉嫩度起到主要作用。研究表明,磷酸化修饰参与钙蛋白酶系统复杂的活性调控过程。本文概述了μ-/m-钙蛋白酶和钙蛋白酶抑制蛋白磷酸化研究的最新进展,根据它们的磷酸化对其结构和功能的影响,探讨钙蛋白酶系统磷酸化修饰对宰后肉嫩化的作用机制,并对其在肉品质中的应用研究进行展望。     

罗非鱼冷藏期间内源蛋白酶和热休克蛋白70对肌原纤维解离的影响

为研究罗非鱼冷藏期间内源蛋白酶和热休克蛋白70与肌原纤维解离的关系，实验测定了罗非鱼肉在4℃真空包装冷藏48 h内肌原纤维小片化指数、肌原纤维解离、内源蛋白酶活性和热休克蛋白70含量的变化，并对其进行相关性分析。结果表明鱼肉冷藏期间肌原纤维小片化指数变化整体呈增加的趋势，最终为初始值的3.52倍；解离的肌球蛋白重链和肌动蛋白的含量呈升高的趋势，最终分别较初始值提高了70%和65%;pH变化为先减少后略微回升，变化范围为6.5～7.0;组织蛋白酶B、L活性持续增加，组织蛋白酶D和钙激活蛋白酶活性呈先增加后减少的趋势，且分别在8、12 h到达最大值；热休克蛋白70含量为先增加后减少，在4 h时达到最大值，最终相比初始值下降了22.27%;肌原纤维小片化指数与组织蛋白酶B、L活性呈极显著正相关(P<0.01),与肌原纤维解离的肌球蛋白重链和肌动蛋白含量均呈极显著正相关(P<0.01),与热休克蛋白70含量呈显著负相关(P<0.05);热休克蛋白70含量与与组织蛋白酶L呈显著负相关(P<0.05)。组织蛋白酶B、L是影响肌原纤维完整性的关键蛋白酶，热休克蛋白70能与肌原...     

应用蛋白酶进行牛肉嫩化的研究

<正>利用可食性蛋白酶进行肉品嫩化,是常采用的嫩化方法之一,其原理在于蛋白酶可协同组织中的胶原酶,破坏肌间结统组织中的胶原纤维,后者是影响肉品嫩度的主要因素之一.为了探讨利用可食性蛋白酶进行牛肉嫩化的理想方法,并为活牛宰前静注蛋白酶进行牛肉嫩化提供依据,我们对13头黄牛的股二头肌和背长肌样本,进行了蛋白酶溶液嫩化研究.测定嫩化前后牛肉中可浸出羟脯氨酸(HYP)含量,依此比较各处理的嫩化效果.     

大豆发芽过程中蛋白质的水解作用研究

研究大豆发芽过程中内源蛋白酶的蛋白水解作用,分析大豆种子吸水量、内源蛋白酶活性、发芽长度、游离氨基酸含量及发芽后大豆蛋白质亚基组成的变化。结果发现,大豆在发芽48h以后,大豆芽表现出快速的增长,其内源蛋白酶的活性达到最高,水解物游离氨基酸的含量变化规律与蛋白酶的活性变化规律一致。大豆发芽过程中,内源蛋白酶主要使11S大豆球蛋白的碱性亚基B3发生降解,对贮藏蛋白的主要成分7S和11S几乎没有作用。     

钙蛋白酶系统对肉的嫩化作用研究进展

肉的嫩度是肉品质的一个重要指标,严重影响肉的食用价值和经济价值.钙蛋白酶系统通过水解肌原纤维蛋白,在宰后肌肉嫩化中起着决定性的作用.综述钙蛋白酶系统(包含钙蛋白酶、钙蛋白酶抑制蛋白和钙蛋白酶激活蛋白3部分)对肉嫩化的作用机制和研究现状,并探讨研究前景.     

几种肉类蛋白酶嫩化剂的比较

对几种肉类蛋白酶嫩化剂对肉类嫩化效果进行了比较，介绍了不同蛋白酶嫩化剂作用效果不同之处。认为弹性蛋白酶是一种较符合理想肉类嫩化剂的蛋白酶类。     

中间型极限pH值牛肉嫩度劣变机制的研究进展

嫩度是衡量牛肉食用品质优劣的重要指标之一,也是消费者选择购买与否的重要标准。相较于高极限pH值(ultimate pH,pHu)(pHu6.2)和正常pHu(pHu5.8)牛肉,中间型pHu(5.8pHu≤6.2)牛肉的嫩度较差,且需要更长的成熟时间才可达到理想嫩度。当前,关于中间型pHu牛肉的嫩化机制尚鲜有系统总结。因此,本文通过对比不同pHu牛肉宰后细胞骨架蛋白的降解程度,内源酶系统(钙蛋白酶、组织蛋白酶、细胞凋亡酶与蛋白酶体)在不同pHu牛肉中的作用规律,以及小热休克蛋白在中间型pHu牛肉中表达的特性,综述了中间型pHu牛肉嫩度发生劣变的原因,以期为改善中间型pHu牛肉的嫩度提供依据。     

Calpain and cathepsin activities in post mortem fish and meat muscles

Post mortem tenderization is one of the most unfavourable quality changes in fish muscle and this contrasts with muscle of mammalian meats. The tenderization can be partly attributed to the acid lysosomal cathepsins and cytosolic neutral calcium-activated calpains. In this study, these proteases from fish and bovine muscles were quantified and compared. The cathepsin B and L activities were in more important amounts in sea bass white muscle than in bovine muscle. On the other hand, cathepsin D activity was 1.4 times higher in meat that in fish muscle, while cathepsin H was negligible in both muscles. Calpain activities were similar in both types of muscle. Moreover, calpastatin (calpain endogenous inhibitor) level is 3.9 times higher in sea bass white muscle. These differential activities are considered in relation to their probable involvement in post mortem degradation of muscle.     

Acceleration of Postmortem Tenderization in Ovine Carcasses Through Activation of Ca2+ -Dependent Proteases

Infusion of lamb carcasses with 0.3M CaCl₂ resulted in acceleration of postmortem tenderization process. Control and treated animals had similar cathepsin B, H, and L activities. Various control groups had similar CDP-I, -II and inhibitor activities, whereas these were all decreased in CaCl₂ infused animals. Hence, it was concluded that the activation of Ca²⁺ -dependent proteases was responsible for the observed postmortem proteolysis and tenderization and, it seems unlikely that activity of these cathepsins is related to postmortem tenderization under conditions used in this experiment.     

Exogenous Proteases for Meat Tenderization

The use of exogenous proteases to improve meat tenderness has attracted much interest recently, with a view to consistent production of tender meat and added value to lower grade meat cuts. This review discusses the sources, characteristics, and use of exogenous proteases in meat tenderization to highlight the specificity of the proteases toward meat proteins and their impact on meat quality. Plant enzymes (such as papain, bromelain, and ficin) have been extensively investigated as meat tenderizers. New plant proteases (actinidin and zingibain) and microbial enzyme preparations have been of recent interest due to controlled meat tenderization and other advantages. Successful use of these enzymes in fresh meat requires their enzymatic kinetics and characteristics to be determined, together with an understanding of the impact of the surrounding environmental conditions of the meat (pH, temperature) on enzyme function. This enables the optimal conditions for tenderizing fresh meat to be established, and the elimination or reduction of any negative impacts on other quality attributes.

[Supplementary materials are available for this article. Go to the publisher's online edition of Critical Reviews in Food Science and Nutrition for the following free supplemental files: Additional text, tables, and figures.]     

牛肉的外源性蛋白酶嫩化技术研究进展

牛肉嫩度是一项肉质评定的重要指标,也是消费者评判肉质优劣的最常用指标.外源性蛋白酶嫩化技术具有方法简单,条件要求相对低,能显著提高牛肉的品质等优点,且处理后的牛肉具有柔软、适口、多汁和易于咀嚼等特点,多年来一直受到肉类加工行业的重视,并已得到了广泛的研究和应用.本文主要论述了外源性蛋白酶对牛肉的嫩化机理和近年来在利用各类外源性蛋白酶嫩化处理牛肉的研究上取得的进展,以期为牛肉嫩化的研究提供参考.     

细胞凋亡对肌肉宰后嫩化的贡献

嫩度是肉品最重要的品质指标,而成熟是改善肉的嫩度的重要途径。肉成熟嫩化的原因普遍认为是肌细胞的细胞骨架降解造成的。目前,细胞骨架降解的机理研究方面报道较多的是钙激活酶系统、组织蛋白酶系统和蛋白酶体,而有关细胞凋亡酶在肉成熟中的作用国内外还鲜见报道。本文综述了宰后肌细胞内生理条件的变化,以及细胞可能选择的死亡方式,即凋亡;概述了能作为caspase酶家族底物的几类主要的肌细胞骨架蛋白;对常用的几类诱导细胞凋亡的细胞毒素进行了介绍;最后,对细胞毒素注射应用于宰后牛肉品质形成机理研究的潜在意义进行了探讨。     

POSSIBLE ROLE OF MUSCLE PROTEINS IN FLAVOR AND TENDERNESS OF MEAT

Evidence suggests that both the myofibrillar proteins and collagen play important roles in meat flavor and tenderness. The probable contributions of the purified proteins to flavor are reviewed in terms of their amino acid composition, especially the sulfur containing and certain other amino acids that have been implicated in meat flavor development. Myofibrils solubilized in sodium dodecylsulfate (SDS) undergoproteolysis on warming to room temperature overnight or on storing for several days at 0–4°C as demonstrated by extra protein bands. The extra proteins appear to be due to the presence of indigenous muscle proteases. The implications of some indigenous muscle proteases are reviewed in terms of their probable role in tenderization of postmortem meat.     

Physical Interventions to Manipulate Texture and Tenderness of Fresh Meat: A Review

Meat tenderness is a major eating quality attribute that ensures consumer satisfaction and repeat purchase of red meat. The variability in meat tenderness is related to several factors that are spread across the production chain (biological, on farm, processing, and consumer factors), which can lead to inconsistent tenderness in fresh red meat products. The tenderization process is dictated by physical and biochemical factors, which appear to affect the proteases involved in protein degradation and, consequently, they regulate the rate and extend of tenderization in meat. Several physical, chemical, and biochemical interventions have been investigated to improve the tenderness of meat. The present review discusses the physical interventions used to manipulate the texture of meat and their mechanism of action, optimal tenderizing conditions, and their effects on other meat quality attributes (colour stability, lipid oxidation, and water holding capacity). Attention should be paid to other quality attributes for full evaluation of the differing interventions.     

牛肉嫩化与保鲜技术研究进展

本文概述了牛肉的各种嫩化与保鲜方法,主要包括盐类处理嫩化、酶法嫩化、超声波嫩化、高压嫩化以及复合保鲜剂保鲜、涂膜保鲜和气调保鲜,并阐明了它们的作用机理,为牛肉嫩化、保鲜的进一步研究提供参考。     

Functional characterization of purified pear protease and its proteolytic activities with casein and myofibrillar proteins

This study was performed to characterize pear protease proteolytic activity and investigate the use of pear protease as a meat tenderizer. Pear protease was purified and stabilized by 5% dextrin during lyophilization (dry) or concentration (liquid). Pear protease was further characterized with respect to pH, thermodynamics, and enzyme kinetics. Pear protease was stable at a pH range of 5-8 with an optimum pH of 6.5. From Arrhenius plots, liquid protease showed higher temperature dependency (23.49 kJ/mol) than dry protease (18.62 kJ/mol) due to its higher activation energy. The kcat/Km, catalytic efficiency of enzyme, was similar with 2.9 and 2.7 µM/min with dry and liquid proteases. Pear protease was evaluated for its proteolytic activities with casein and beef myofibrillar proteins by individually and combination with fig and kiwifruit proteases. These result indicated that pear and kiwifruit proteases could be complementary to be a desirable product for meat tenderization.