牛肉嫩化技术的研究进展

肉品嫩度是肉的首要食用品质,它是消费者评判肉质优劣的最常用指标。肉嫩度的改善,多年来一直是国内外肉品科学研究的热点之一。宰后肉类的后期成熟和嫩化处理,是改善肉品嫩度的关键环节。对影响肉嫩度的宰前和宰后因素、目前嫩化方法及嫩化机制进行综述,最后对肉的嫩化趋势作出展望。     

宰后僵直温度对肉嫩度的影响

肉的嫩度差和不一致性是肉类屠宰加工工业面临的两大难题。宰后24 h内的胴体/肌肉的温度决定肉嫩度的水平。研究论述了宰后僵直温度对肌肉收缩与成熟过程内源蛋白酶的影响,探讨了宰后温度对肉嫩度影响的机制,进而讨论了p H-温度窗口,以期为屠宰加工企业优化胴体冷却温度提供参考。     

低压电刺激和高压电刺激对肉品质的影响

电刺激可以改变肉的品质，不论高压电刺激还是低压电刺激都对肉的嫩度有重大改善，虽然改善嫩度最好的处理是在宰后２０分钟时用高压电刺激，然后速冻，但失水多、外观品质下降大。宰杀后２０分钟低压电刺激也改善了肉嫩度，并且不影响肉的外观，失水量也没高压刺激多。宰后立即低压电刺激则增加了水损失。因此，宰后２０分钟低压电刺激对肉品质改善是最佳的。电刺激后的肉在第３天或第１０天嫩度进一步改善，而不经电刺激的肉一直坚     

动物宰后肌内胶原蛋白变化与肉嫩度关系分析

动物肌内结缔组织对肉的嫩度起到重要的影响作用,这些影响主要是通过肌内膜和肌束膜内胶原蛋白的变化而影响肉的嫩度,表现为胶原蛋白的含量、热溶解性、交联程度以及热变性程度等.而胶原蛋白的这些特性还受到动物宰前和宰后诸多不同因素的影响,进而影响到肉的嫩度,本文综述了胶原蛋白在宰后成熟、加热烹调、超声波和高压嫩化处理以及弱有机酸结合NaCl腌制中的变化,分析和阐述了胶原蛋白的变化对肉嫩度的影响.     

宰后肉的嫩化机制及其影响因素

宰后肉类的后期成熟和嫩化处理,是改善肉品质（嫩度）的关键环节。本实验阐述了影响宰后肉嫩度的因素（pH值、胶原蛋白和钙激活酶）和相关嫩化机理（有机酸、电刺激、盐类、外源酶和内源酶、超声波、高压和吊挂拉伸的嫩化机理）。     

肉类嫩化的理论、方法及前景

近十多年来,肉类嫩化理论及加工工艺研究一直是肉品学科中的热点之一。了解肉的嫩化机理可以更好地加速肉嫩化的过程。嫩化技术为宰后嫩化技术和宰前嫩化技术。牲畜宰前肉的嫩化如适龄牲畜在出栏前,日粮中适当加入VD3、VE,或使牲畜适当运动。综述了电刺激、钙处理、外源酶处理、机械嫩化、pH处理、高压处理、冲击波处理等影响肉类嫩度与品质的因素及嫩化的技术理论和方法。     

应用蛋白质组学研究肉品品质形成的机理

品质是肉品食用价值和商业价值的基础。基因型、宰前管理及宰后处理等诸多因素影响动物组织的新陈代谢和宰后肌肉到食用肉转变过程中的生化过程,在上述过程中肌肉蛋白质组的变化贯穿始终,最终决定肉的品质。文中综述牛肉、猪肉和鸡肉在品质形成过程中蛋白质组的变化,阐述了肌肉到食用肉的转变过程中发生的分子变化,及其宰前因素和宰后加工对肉品品质(如嫩度、肉色、脂肪沉积)的影响及其机理。     

影响肌肉嫩度的因素及常用的嫩化方法

肉的品质受多方面因素的影响,其中最重要的一个因素就是嫩度,它直接影响着肉的食用价值和商品价值,反映着肉中各种蛋白质的结构特性。影响肉嫩度的因素有很多,本文从宰前因素和宰后因素对肌肉嫩度的影响以及常见的嫩化方法作了阐述。     

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。     

宰前处理对畜禽肉品质影响的研究进展

综述了宰前运输、禁食、静养及致晕方式对畜禽宰后肌肉pH、肉色、持水力及嫩度等肉质特性的影响。宰前处理产生的应激反应会改变畜禽宰前体内糖原含量,改变宰后肉中糖酵解和蛋白质降解程度。宰前处理也可能通过应激激素和宰后肉pH变化来影响肉中内源蛋白酶活性,从而导致肉质差异。其中宰前处理造成的宰后糖酵解改变是影响肉质的主要因素。开展针对不同畜种的宰前处理研究,制定出一套适合我国生产实际的宰前处理操作规范,可以避免宰前处理对肉质造成的消极影响,为优质肉的生产提供保障。     

Influence of cooking conditions on cooking loss and tenderness of raw and marinated chicken breast meat

The influence of different cooking treatments on tenderness and cooking loss, as main quality characteristics of chicken breast meat, was investigated. Industrial skinless chicken breast meat samples were designated as raw and marinated and cooked in the oven by hot air and hot air-steam mixture at 130, 150 and 170 °C, for 4, 8 and 12 min. Cooking losses were evaluated by weight changes before and after cooking, and tenderness changes were determined on cooked samples by measuring shear force using instrumental texture analysis. Results showed that marination, followed by air-steam cooking is the best combination to obtain the most tender chicken breast slices. The time and temperature of cooking showed similar effects on cooking loss and tenderness: short cooking time (4 min) and temperatures of 130–150 °C resulted in lower cooking losses and best meat tenderness, in both not marinated and marinated meat. Statistically significant correlations between tenderness and cooking loss indicated that the cooking loss correlated better with cooking time than with cooking temperature. An opposite phenomenon was observed for meat tenderness.     

牦牛肉品质特性研究进展

牦牛肉是我国青藏高原的重要畜牧产品之一,在当地居民的膳食及高原地区的经济发展中占据重要地位。了解牦牛肉的肉质特性对于牦牛肉的精深加工和牦牛资源的合理开发有重要意义。本文综合近几年国内外相关研究,从营养品质、食用品质和加工品质3 个方面对牦牛肉的品质特性进行概述和分析,以期为牦牛肉的品质改善和产品开发提供参考和思路。牦牛肉营养价值高、绿色无污染、市场潜力大,但嫩度较差,今后需借助适当饲养方式和宰后处理方式对其嫩度进行改善。     

Tenderisation of meat by pressure-heat involves weakening of the gap filaments in the myofibril

These results confirm previous Australian experience that pressure-heat (P-H) treatment tenderises rigor meat effectively only after considerable periods at elevated temperatures; that prior ageing abolishes the effect; and that cold shortened meat is effectively tenderised. Yield point is also profoundly affected by P-H, although this effect is not related to tenderness. As predicted by the new G-filament theory of meat tenderness, P-H greatly weakens the G-filaments. These then break on extension by 50% but not if subsequently cooked. However the tensile properties of cooked meat support the weakening of G-filaments. A problem is that mild P-H treatments which are ineffective at tenderising, produce the same histological damage as harsher tenderising treatments. This paper reviews the considerable body of results on the P-H treatment of rigor meat that have now accumulated. The effects of pressure on the various filaments is discussed. The nature of the changes induced in the G-filaments remains obscure.     

包装方式和宰后不同时间包装对羊肉品质的影响

为探究包装方式和宰后不同时间包装对羊肉贮藏品质的影响,本研究对宰后1 h热分割羊肉和冷却成熟24 h后的分割羊肉分别进行热收缩包装、真空包装、贴体包装、50%（体积分数,下同）O2+50%CO2气调包装,测定其在（2±2）℃贮藏过程中pH值、色泽、贮藏损失率、蒸煮损失率、离心损失率、剪切力、挥发性气味的变化。结果表明：与宰后24 h包装相比,宰后1 h包装羊肉pH值在贮藏14 d时更高,但其贮藏期间色泽较好,色泽稳定性更高,贮藏损失率更低。从整体来看,3种真空处理（热收缩包装、真空包装、贴体包装）羊肉嫩度均优于气调包装羊肉,且宰后1 h包装时真空条件处理对羊肉嫩化效果最好,宰后24 h羊肉在贮藏前期气调包装对羊肉嫩化效果较好;而无论何时包装,热收缩包装和气调包装羊肉贮藏损失率均显著小于其他处理组（P<0.05）,在贮藏前期色泽及稳定性较好,但贮藏后期色泽稳定性下降明显,气调包装羊肉在14 d时已部分发绿,贮藏21 d时挥发性气味变化显著。综上,宰后1 h包装有利于提高羊肉贮藏期间色泽及持水力,改善真空处理羊肉嫩度,宰后24 h包装可提高50%O2+50%CO2气调包装羊肉贮藏前期...     

Effect of Pulsed Electric Field Treatment on Cold-Boned Muscles of Different Potential Tenderness

Despite the release of several reports highlighting the potential benefits of pulsed electric field (PEF) technology in food processing, there are limited studies on the use of PEF in meat processing, in particular with fresh meat. The effect of PEF on the quality of beef loins (Musculus longissimus lumborum, LL) at 1 day postmortem and topsides (Musculus semimembranosus: SM) at 1 and 3 days postmortem was investigated using a range of treatment combinations [voltages (5 and 10 kV) and frequencies (20, 50 and 90 Hz)]. The investigated parameters were purge loss, cooking loss and meat tenderness (shear force) to identify the optimum PEF treatment conditions for each muscle to evaluate the economic (in terms of purge and cooking losses) and texture benefits of PEF treatments. The tenderness of the loin samples was found to benefit from PEF treatment (19.5 % reduction in the shear force) regardless of the electrical input, whereas the level of tenderness of the topsides was increased by increasing the treatment frequency (4.1, 10.4 and 19.1 % reduction in the shear force at 20, 50 and 90 Hz, respectively). Higher purge loss (%) and lower cooking loss (%) were found in PEF-treated samples. It is interesting to observe that the level of SM tenderness improvement was not dependent on the meat postmortem time up to 3 days which allows greater flexibility in the use of PEF technology.     

肉类嫩度形成机理及嫩化调控研究进展

嫩度是原料肉的重要品质指标之一,与肉制品的出售价格及消费者满意程度和重复购买的意愿紧密相关。近年来,新兴的植物肉、细胞培养肉等人造肉追求模拟传统肉制品的感官体验,其中包括肉类独特的质地。本文对肉类嫩度的主要影响因素及近年来的研究进展进行综述。首先,简要介绍嫩度的定义及测定方法;其次,围绕肌节长度、结缔组织和蛋白酶解三方面重点介绍肉类嫩度的影响因素及机理;最后,简述肉类嫩度的调控方法及最新的研究进展,以期为传统肉品领域以及模拟肉、3D打印肉等相关研究开发提供参考。     

Effect of replacing soybean meal by extruded chickpeas in the diets of growing-finishing pigs on meat quality

The main objective of this study was to evaluate the effect of the replacement of soybean meal by extruded chickpeas in diets of growing-finishing pigs on meat quality. In a 17wk study 48 growing-finishing crossbred pigs were fed ad libitum. The experimental design included four treatments, each one of 12 pigs; the ECKP0 treatment was fed with diet containing soybean meal and no chickpeas (control), while treatments ECKP100, ECKP200 and ECKP300 were fed with diets containing 100, 200 and 300kg/t of extruded chickpeas, respectively. The lean meat quality of the longissimus lumborum et thoracis muscle was evaluated by chemical analysis (moisture, protein, fat and ash), fatty acid profile, pH measurement, cooking loss, color evaluation, and sensory evaluation. Odor and taste, tenderness, juiciness, and overall acceptability were scored on 1-10 scales by a group of 10 experienced assessors after a standard cooking regime. Small differences were observed between control and experimental groups in chemical composition (P>0.05). Fatty acid profiles, pH measurements and color evaluation did not differ among treatments (P>0.05), while cooking loss was significantly lower in the control group (P<0.05). The taste panel gave slightly higher scores for the tenderness and juiciness for the control group compared with the chickpea treatments (P<0.05). No differences were observed between control and experimental groups in taste scores (P>0.05). It is concluded that the replacement of soybean meal by extruded chickpeas, when substituted isonitrogenously and isoenergetically at inclusion levels up to 300kg/t of pig, does not influence significantly meat quality.     

Effect of calcium infusion on tenderness and ageing rate of pork m. longissimus thoracis et lumborum after accelerated boning

The effect of calcium chloride infusion at either 0.5 or 6 h post slaughter on tenderness, ageing rate and meat quality of pork longissimus muscle that had been boned at rigor or had undergone accelerated processing and conditioning at either 0?°C or 14?°C was investigated. The time of calcium infusion had no effect on the initial WBSF values or the aging rate. However, calcium infusion overall resulted in lower WBSF initially (1-day post-mortem) and also after 6 days ageing at 2?°C regardless of the processing procedures used. Calcium infusion did not, however, increase the ageing rate compared to comparable treatments that had not been calcium infused. Based on this observation and the myofibrillar fragmentation index results, it was concluded that the increased tenderness due to calcium infusion was not due to increased proteolysis as has been previously postulated, but was due to either a direct effect of calcium on tenderness, or an indirect effect of calcium via increased post-mortem glycolysis and pH decline rate resulting in reduced cold shortening. Calcium infusion had detrimental effects on drip loss and meat colour.     

宰后肌肉蛋白质变化与嫩度的关系

肉的嫩度受很多因素影响,但目前对其机理的认识仍非常有限。本文综述了近年来国内外学者对肉嫩度的研究,主要分析了宰后蛋白质变化对肉嫩度的影响,以期为肉嫩度的提高和品质的改善提供参考。