骨架蛋白肌联蛋白、伴肌动蛋白、纽蛋白的降解对冷却猪肉持水性的影响

肉的持水性可用许多指标衡量,而汁液流失率(drip loss)是其中一个重要指标.持水性受很多因素影响,但目前对形成汁液流失的机理的认识还很有限.本文综述了近几年来国内外学者对持水性的研究,主要分析了宰后骨架蛋白(肌联蛋白、伴肌动蛋白、纽蛋白)的降解及钙激活蛋白酶系统降解骨架蛋白对持水性的影响,以期为宰后猪肉持水性提高和肉品质改善提供参考.     

影响冷鲜猪肉保水性因素的研究

肉的保水性是一项重要的肉质指标,保水性的高低与肉品质量和商品价值密切相关。主要分析了遗传、饲养、管理、运输应激、屠宰、宰后等方面因素,分别阐述了冷却肉在流通过程中汁液流失的影响,对研究提高肌肉保水性和降低滴水损失的技术具有极其重要的意义。     

基于微观结构和蛋白质组学分析影响猪肉持水性的差异蛋白

为探究宰后初期生鲜猪肉肌细胞微观结构和蛋白质组变化对持水能力的影响,将猪背最长肌样品按照汁液流失的高低分为高汁液流失组（High drip loss group≥5.93%, H组, n=3）和低汁液流失组（Low drip loss group≤0.81%, L组, n=3）,对两组样品的微观结构和蛋白质组进行比较。采用透射电镜（Transmission Electron Microscopy, TEM）观测细胞间隙,并用多肽体外标记技术（Tandem Mass Tag, TMT）鉴定高低汁液流失组间的差异蛋白。结果表明,宰后24 h时,H组的细胞外间隙极显著大于L组的细胞外间隙（P<0.01）。宰后肌肉中葡萄糖磷酸变位酶-1、热休克蛋白70（Heat shock protein 70, Hsp70）、锚蛋白、硒蛋白W和层黏连蛋白的表达量越高,汁液流失越低,持水性越好,而磷酸甘油变位酶和转酮醇酶的表达量越高,汁液流失越高,持水性越差。     

猪屠宰后正常肉与PSE肉中整联蛋白变化与持水性的相关性

采用蛋白印迹(Western blot)和组织学微观测量技术测定猪宰后正常肉和PSE肉(Pale,Soft,Exudative)中整联蛋白(integrin)降解情况和肌肉组织微观结构变化,并分析integrin对肌肉持水性的影响。结果显示:integrin在宰后逐步降解,正常肉和PSE(Pale,Soft,Exudative)肉样integrin的降解量差异不显著(p0.05)。同组内比较,正常组在宰后第24 h出现明显降解(p0.05);PSE组在宰后6 h出现显著降解(p0.05)。宰后2 d的integrin完整度与汁液流失率呈显著负相关(p0.05),宰后两组肉样的肌肉细胞间隙面积呈显著性增加(p0.05),PSE组细胞间隙显著高于正常组的细胞间隙面积。宰后猪肉样品在宰后1、6、24 h的细胞间隙面积与汁液流失率呈极显著正相关(p0.01)。实验结果表明:宰后integrin降解越少,细胞间隙面积越小,汁液流失率越小,肌肉持水力越强。     

宰后猪肉pH值、骨架蛋白表达水平和持水性之间的关系

以20 头猪的背最长肌为材料,分别于宰后45 min和3、9、12、24 h测定猪背最长肌的pH值和整联蛋白、黏着斑蛋白、踝蛋白表达水平,并测定汁液流失率,探讨它们之间的关系。结果显示：高pH组（pH45 min≥6.00,n＝6）的汁液流失率和踝蛋白表达水平低于低pH组（pH45 min≤5.78,n＝14）,整联蛋白和黏着斑蛋白表达水平高于低pH组。pH值和整联蛋白、黏着斑蛋白表达水平与汁液流失率呈负相关,踝蛋白与之相反。pH值和整联蛋白、黏着斑蛋白、踝蛋白表达水平分别解释了汁液流失率变异的77%、41%、44%和34%。上述结果表明：pH值和骨架蛋白变化都会对猪肉持水性产生影响,但pH值的降低对猪肉持水性的影响比骨架蛋白降解影响更大。pH值会通过影响细胞骨架完整性,进而影响最终产品的持水性。宰后45 min的pH值可以用于预测宰后猪肉的汁液流失率。     

蛋白质氧化对肉类成熟的影响研究进展

在肉的宰后成熟过程中会伴随着肌肉蛋白质的氧化并导致肉的食用品质劣变。本文综述近年来在肉品领域关于蛋白质氧化的研究成果,主要阐述肌肉蛋白质氧化机制以及蛋白氧化对肉宰后成熟的影响,包括对肉色、嫩度、持水力及营养价值等食用品质指标的影响,旨在为有关肉类蛋白氧化研究提供一定的参考,并对未来的研究方向进行展望。     

畜禽宰后肌肉能量代谢与肉品质研究进展

畜禽宰后肌肉通过糖酵解等能量代谢途径提供ATP满足能量需要,产物乳酸的生成会降低pH。糖酵解的速度和程度影响了pH的下降速度和程度,进而调控肉品色泽、嫩度、持水性、多汁性、风味等品质。本文综述了畜禽宰后肌肉能量代谢的基本路径,论述了腺苷酸激活蛋白激酶对糖酵解的调控机理及其对肉品质的影响,并着重叙述了白肌肉(pale soft and exudative meat,PSE)的预防措施,为在生产过程中肉品质调控提供思路。     

宰后糖酵解对肉品质影响的研究进展

宰后糖酵解作用在肌肉宰后变化过程中起到至关重要的作用。糖酵解系统的各组分,如肌糖原,糖酵解酶等,以及糖酵解潜力和糖酵解速率都是影响宰后肉质量变化的主要因素,它们的变化影响极限pH值(pHu)或受极限pH值(pHu)影响,进而影响色泽、嫩度、持水性、多汁性、风味等直接反映肉品质的指标。本文针对宰后糖酵解对肉品质影响的研究进展作一综述。     

磷脂酶活性对冷却肉持水性的影响

对正常肉和PSE肉样的肉质特性和磷脂酶活性进行了测定和分析。宰后PSE肉的pH1h和pH24h低于正常肉,而L值(宰后1h、24h)、脂肪氧化程度、汁液流失率、贮藏损失、蒸煮损失和磷脂酶A2总活性明显高于正常肉。冷却肉的汁液流失率与pH1h和pH24h呈强负相关,与T1h、磷脂酶A2总活性和非钙依赖型磷脂酶A2呈显著正相关。结果说明,宰后的低pH、宰后早期肌肉高温和磷脂酶A2活性对冷却肉汁液流失有重要作用。     

冷却肉肌肉保水性及其影响因素

本文主要介绍了冷却肉、肌肉保水性及影响肉保水性的因素,从遗传因素、饲养因素、管理因素、运输应激、屠宰因素、宰后因素等方面分别阐述了冷却肉在流通过程中汁液流失的影响因素,对研究提高肌肉保水性和降低滴水损失的技术具有极其重要的意义。     

The effect of ageing on the water-holding capacity of pork: role of cytoskeletal proteins

The water-holding capacity (WHC) of pork decreases post-mortem but has been shown to increase during subsequent ageing. In order to test a hypothesis that water-holding capacity increases during ageing due to degradation of the cytoskeleton, WHC was followed 10 days post-mortem and related to the extent of proteolysis of cytoskeletal proteins. A fast method for measuring WHC in small meat samples was developed by the use of centrifugation. The WHC of fresh pork decreases in the first part of post-mortem storage after which it increases to the level of 1 day PM. No changes in total water content of the meat were observed which could explain changes in WHC during ageing. Vinculin and desmin degrade gradually during ageing while talin degrades rapidly. These observations are consistent with the hypothesis that degradation of the cytoskeleton slowly removes the linkage between lateral shrinkage of myofibrils and shrinkage of entire muscle fibres, so removing the force that causes flow into the extracellular space. Inflow of previously expelled water is then possible, so increasing WHC as observed in later periods of storage.     

肉及肉制品持水性测定方法的研究进展

本文对测定猪肉持水性的方法进行了综述,并对各种测定方法的优劣进行了评价。结合现代肉类工业发展的特点,认为对于鲜肉持水力的测定选择EZ-driploss法和核磁共振法比较合适,而对于肉制品则可以选择拿破率和蒸煮损失法测定。     

屠宰因素对肌肉保水性影响的研究进展

肉的保水性是肉的重要品质指标之一,与肌肉的其它品质指标如颜色、风味、嫩度等有着密切联系。研究肌肉保水性的影响因素对于改善肉的整体品质和减少因滴水损失造成的经济损失具有重要价值。影响肌肉保水性的因素很多,而目前国内相关研究很少,本文综述了近年来屠宰因素对肌肉保水性影响方面的国内外最新研究进展。     

Effect of salt and phosphate on the quality of Buffalo and Goat meats

A study was conducted on the effect on certain quality parameters of adding sodium chloride (2·5%) and tetrasodium pyrophosphate (1%) to hot minced buffalo and goat meats. The effects on buffalo meat were observed in chilled and frozen conditions, those on goat meat in hot and chilled conditions. These treatments significantly increased pH, water-holding capacity (WHC) and emulsifying capacity (EC) and decreased cooking loss in both types of meat. Chilled and frozen conditions did not affect buffalo meat quality but salt additions to hot minced goat meat were superior to such additions to chilled minced meat in respect of EC and the extraction of salt-soluble proteins. Buffalo meat had poorer WHC and EC than goat meat and salt additions had a greater effect in improving EC. With goat meat, the treatment resulted in an increased WHC with a greater increase in pH. Significant correlations were observed among quality parameters.     

Factors affecting the water holding capacity of red meat products: a review of recent research advances

The water holding capacity of meat products is a very important quality attribute which has an influence on product yield, which in turn has economic implications, but is also important in terms of eating quality. A number of pre-and post-mortem factors influence the water holding capacity (WHC) of meat. During the growth and development of meat animals, genotype and animal diet are important due to their direct influence on muscle characteristics. In the immediate pre-slaughter period, stresses on the animal such as fasting, and different stunning methods are likely to influence meat WHC. In the post-slaughter period chilling, ageing, injecting non-meat ingredients, as well as tumbling have important influences on WHC. Furthermore, cooking and cooling procedures for the final meat products can also affect the WHC of the product, in particular the cooking and the cooling methods, the heating and the cooling rate, the cooking temperature, and the endpoint temperature. This paper provides an overview of recent research on important intrinsic and extrinsic factors that affect the WHC of beef, pork, and lamb products, and reveals explanations and solutions to some of the critical problems related to WHC and product quality.     

Influence of the season on the relationships between NMR transverse relaxation data and water‐holding capacity of turkey breast meat

In the last few years the poultry industry has seen a significant deterioration in meat quality properties during the summer season. The objective of this study was to evaluate the seasonal effect (summer and winter) on turkey meat quality assessed by both conventional and low‐resolution nuclear magnetic resonance (LR‐NMR) analysis. Eighty‐eight breast muscle samples (35 winter and 53 summer) from BUT‐Big 6 turkeys belonging to 16 different flocks, were randomly collected from a commercial processing plant. The samples were analysed for transverse relaxation times (T₂) by LR‐NMR and for initial pH (15 min post mortem), ultimate pH (24 h post mortem) and pH after cooking, temperature at 15 min post mortem, water‐holding capacity (WHC, drip loss, filter paper press wetness and cooking loss) at 24 h post mortem, colour of raw and cooked meat and chemical composition (moisture, lipids and proteins). The results indicate that, during the summer season, turkey breast meat undergoes a relevant WHC decrease. Cluster analysis of the raw LR‐NMR data evidenced the presence of two groups corresponding to samples harvested in each different season. Correlations between the LR‐NMR signal and the conventional parameters measuring WHC were obtained by a recently proposed type of principal component regression (PCR) termed relative standard deviation PCR. Copyright © 2004 Society of Chemical Industry     

宰前处理和冷却方式对猪肉品质的影响

本文对宰前处理方式、致晕方法和冷却方式对猪肉品质(肉色、滴水损失/持水性-WHC和电导率)的影响进行了比较总结,旨在对屠宰行业在控制肉品质,减少PSE发生方面提供参考。     

Centrifugal drip is an accessible source for protein indicators of pork ageing and water-holding capacity

Achieving an improvement in water-holding capacity (WHC) of pork and a reduction in the incidence of pale, soft and exudative (PSE)- and dark, firm and dry (DFD)-like meat is a major challenge for the swine industry. Using proteomics, we sought to identify proteins associated with WHC and to monitor postmortem protein degradation. Twenty longissimus samples were categorised into WHC phenotypes. The centrifugal drip was subjected to SDS-PAGE and mass-spectrometry. Forty-four proteins were identified in the centrifugal drip proteome. Changes occurred in volume of five bands across the ageing period, with most significant changes representing increases between day 3 and day 7. Seven proteins were identified in these bands, most with functions in glycolysis. One band significantly differed in abundance across WHC phenotypes. Peptide signatures of the heat shock protein family were identified in this band.     

肌原纤维蛋白热诱导凝胶特性研究进展

肌原纤维蛋白质是肌肉中一类重要的结构蛋白质群,它对于肉食制品的品质和特性具有非常重要的影响.肌原纤维蛋白的凝胶特性是形成肉制品独特的质构、保水性、乳化性以及感官特性的决定性因素.本文介绍了肌原纤维蛋白凝胶机制、功能特性及其影响因素,为进一步了解肉制品加工特性提供一定理论指导.     

滩羊肉宰后成熟期间ATPase活力变化对微观结构及保水性的影响

为研究宰后成熟期间ATPase活力变化对滩羊肉微观结构以及保水性的影响,以6 月龄滩羊背最长肌（Longissimus dorsi）为研究对象,分析其4 ℃成熟0、1、2、4、8 d时Na＋-K＋-ATPase、Ca2＋-ATPase、Caspase-3活力以及肌肉微观结构、pH值与滴水损失率的变化情况。结果表明：随成熟时间延长,Na＋-K＋-ATPase与Ca2＋-ATPase活力先升高后降低,成熟1 d时达到最大值;Caspase-3活力先升高后降低,成熟2 d时达到最大值;滴水损失率先升高后降低,pH值先降低后有所回升;总蛋白、低盐溶性蛋白及高盐溶性蛋白质量浓度均逐渐减少,水溶性蛋白质量浓度成熟2 d后显著降低（P＜0.05）;成熟至8 d时,肌原纤维断裂,肌纤维之间、肌束之间、肌纤维及肌膜之间形成间隙,Z线断裂,H带消失;相关性分析结果表明Na＋-K＋-ATPase活力与各指标均呈极显著相关性（P＜0.01）,Ca2＋-ATPase活力与pH值、Na＋-K＋-ATPase及Caspase-3活力均呈极显著相关性（P＜0.01）。结论：滩羊肉宰后成熟过程中Na＋-K＋-ATPase与Ca2＋-ATPase活力变化可能促使下游Caspase-3激活,Caspase-3水解结构蛋白可能导致肌肉组织在不同部位形成间隙,在重力作用下肌肉中的水分流入间隙中,引起滩羊肉滴水损失升高,保水性变差。