线粒体对肉色及其稳定性影响的研究进展

肉色是评价肉品品质最直观的指标,能够直接影响消费者的购买意愿。近40 年有较多学者对影响肉色及 其稳定性的因素进行了概述,但较少涉及线粒体对肉色及肉色稳定性的影响。线粒体与肌红蛋白的氧化还原状态密 切相关,它主要通过影响氧气消耗和高铁肌红蛋白还原来改变肉色及其稳定性,因此影响线粒体结构和功能的因素 也会影响肉色。本文对目前关于线粒体与肉色及其稳定性关系的研究进行综述,概括线粒体对肉色及其稳定性的直 接影响和基于线粒体影响肉色及其稳定性的因素,并阐述其影响机理。     

乳酸盐对冷却肉护色机理的研究进展

肉色是影响消费者购买决策的重要质量参数,肉色劣变带来的经济损失也不可估量,因此护色技术的研究至关重要。近几十年有较多学者对影响肉色及其稳定性的因素进行了概述,但较少涉及到乳酸盐对肉色及肉色稳定性的影响。乳酸盐作为三羧酸循环的中间代谢产物,主要通过其所处的乳酸-乳酸脱氢酶体系促进烟酰胺腺嘌呤二核苷酸(nicotinamide adenine dinucleotide,NADH)的再生进而提高高铁肌红蛋白(metmyoglobin,MMb)的还原,从而达到稳定肉色的作用。此外,脂质氧化也是影响肉色劣变的原因之一,乳酸盐还可通过间接影响脂质氧化调控肉色。因乳酸盐具有安全、健康等优点,目前其已成为肉品护色的研究热点,但其护色机理有待于进一步研究。该文综述了乳酸盐对冷却肉护色机理的最新研究进展,以期为冷却肉的护色提供参考。     

蛋白质氧化和翻译后修饰对肉品质的影响及机制研究进展

动物屠宰后，肌肉向可食肉转变的过程中涉及一系列的生化变化，它们相互影响并决定了肉的品质。其中氧化应激引起的蛋白质氧化以及蛋白质翻译后修饰对肉品质的形成具有重要影响，但鲜见对其机理系统的深入总结报道。本文综述了氧化应激与蛋白质氧化的关系，总结了动物屠宰后蛋白质氧化和翻译后修饰对肉的嫩度、持水性、肉色和营养价值等品质形成的影响及其作用机制，以期为未来肉品科学的研究提供理论参考。     

纳米银诱导微生物氧化应激及其抗菌机制

近年来,为解决致病菌的耐药性问题,多种新型抗菌剂应运而生。其中,银纳米粒子（AgNPs）的抗菌效果颇为突出,受到广泛关注。AgNPs抗菌性涉及生物膜、细胞损伤和基因表达等复杂的生物过程。氧化应激反应在这一生物过程中占据重要地位。在AgNPs胁迫下,微生物胞内产生过量的活性氧（ROS）,激发胞内的氧化应激,并产生以下3个方面的作用：破坏细胞壁、细胞膜及其内容物;影响氧化应激相关基因表达;影响蛋白质翻译过程和代谢通路的变化。基于此,本文将介绍AgNPs胁迫下微生物氧化应激的产生,重点阐述氧化应激在细胞、基因表达、转录组和蛋白组水平对微生物的影响机制,以便深入了解氧化应激在AgNPs抗菌中的作用。     

宰后牛肉色泽稳定性及其影响因素

介绍了宰后影响牛肉色泽稳定性的主要因素及其机理,肌红蛋白的氧化状态是决定鲜肉产品的最主要因素,高铁肌红蛋白还原酶活力对于肌红蛋白氧化状态及肉色稳定性的影响最大,而在宰后储藏过程中各种内源性抗氧化成分对肉色稳定具有重要作用.并建议引入体外孵化和预测模型等相关研究方法.关于影响因子的精确研究对提高肉品色泽品质具有重要意义.     

牛肉肉色的影响因素及其控制技术研究进展

肉色及其稳定性是新鲜牛肉的重要品质指标之一,也是影响消费者选择购买的关键因素。现有研究表明多种因素都会对肉色及其稳定性产生影响。本文综述了在宰前影响机体内抗氧化物质及其浓度的因素(品种、性别、日粮因素和动物管理等)以及宰后因素(成熟时间、不同部位肌肉和肌浆蛋白)对牛肉肉色的影响及其机理,同时总结了部分包装方式、冷杀菌技术(低温等离子体、脉冲电场)和添加外源物对改善牛肉产品肉色及其稳定性的作用。本文可为提高牛肉肉色稳定性和牛肉品质提供相关理论指导。     

迷迭香结合气调包装对牛肉肉色稳定性的影响

生鲜肉在冷藏过程中肌红蛋白会发生氧化导致肉色变暗,迷迭香酸提取物和一氧化碳气调包装(CO-MAP)均可降低肌红蛋白氧化程度,使牛肉保持良好的色泽。研究主要探讨迷迭香提取物结合CO-MAP对冷鲜牛肉肉色稳定性的影响,利用动力学方程筛选迷迭香提取物的最佳添加浓度。结果发现,CO-MAP可显著抑制冷鲜牛肉储藏过程中OMb和MMb的生成,0.4%CO+30%CO_2+69.6%N_2对MMb抑制效果好。添加迷迭香提取物能更好稳定肉色,其中0.015%CAP20对MMb的抑制最为显著(p0.05),a~*显著提高,b~*显著降低(p0.05)。研究表明,迷迭香提取物结合CO-MAP可降低肌红蛋白氧化程度,使牛肉保持良好的色泽,这为日后研究天然抗氧化剂对肉色稳定性的影响提供了理论依据。     

高氧气调包装贮藏牛排肉色稳定性的蛋白质组学

为进一步了解高氧气调包装牛排贮藏过程中肉色稳定性变化的机理,本研究比较了腰背最长肌牛排在各贮藏时间点（0、5、10、15?d）的肉色指标变化以及蛋白质组学变化。结果发现高氧气调包装牛排的肉色稳定性随贮藏时间延长不断降低,这可能是贮藏期间牛排的高铁肌红蛋白还原能力和氧气消耗率显著下降所致;通过蛋白质组学分析,共发现了20?个在贮藏过程中发生显著变化的差异蛋白,其中有15?个蛋白与肉色密切相关,它们主要是一些参与糖酵解和能量代谢的酶类（丙酮酸激酶、3-磷酸甘油醛脱氢酶、果糖-二磷酸醛缩酶、果糖-1,6-二磷酸酶同工酶2、苹果酸脱氢酶和黄素还原酶）,这些代谢酶的表达量随贮藏时间延长发生了不同程度的下调,减少了烟酰胺腺嘌呤二核苷酸和还原型烟酰胺腺嘌呤二核苷酸磷酸的产生,进而降低了肉色稳定性;另外,高氧气调包装贮藏过程中肉色稳定性的降低可能也与肌红蛋白的表达量下调有关;高氧环境还可能会促使抗氧化蛋白2、热休克蛋白以及DJ-1蛋白的表达量上调以抵御肉品的氧化应激反应,这些蛋白也都与肉色指标紧密相关。这些发现表明贮藏期间高氧气调包装对牛排蛋白质组的影响将直接决定其肉色稳定性的变化。     

电刺激对牛肉品质影响研究进展

电刺激是一种通过给畜禽胴体进行电流刺激而加快肉类成熟的技术。该项技术对于宰后牛肉品质有重要影响。目前已有学者对电刺激的作用机理进行了广泛研究,最近在pH-温度窗口理论以及电刺激对肉色和保水性的影响方面有了最新进展。文中首先介绍了pH-温度窗口理论,随后总结了电刺激对胴体的pH值变化、细胞骨架蛋白降解以及肌原纤维结构变化等方面的影响及因此对牛肉品质产生的影响,以此对国内肉牛屠宰企业合理运用电刺激技术提供理论指导。     

乳酸钙对牛肉糜色泽稳定性的影响

为研究乳酸钙对牛肉糜色泽稳定性的影响,将牛背最长肌绞碎成肉糜,分别添加0.1%、0.3%、0.5%的乳酸钙溶液,研究在(4±1)℃的冷藏条件下,肉糜肉色稳定性、色素含量、脂肪氧化及高铁肌红蛋白还原酶活性随时间的变化。结果表明：在7d的贮藏期内,添加不同质量分数乳酸钙均可有效抑制高铁肌红蛋白的生成和脂肪氧化的发生,并显著提高高铁肌红蛋白还原酶活性和肉色稳定性,但会使肉糜L*值显著降低(P＜0.05)。其中0.3%的乳酸钙对稳定肉色有显著作用,护色效果明显。     

Protein Oxidation: Basic Principles and Implications for Meat Quality

The involvement of oxidized proteins to the development of biological diseases has been studied for a few decades, but the effects and the mechanisms of protein oxidation in food systems are largely unknown. Protein oxidation is defined as the covalent modification of a protein induced either by the direct reactions with reactive oxygen species (ROS) or indirect reactions with secondary by-products of oxidative stress. ROS can cause oxidation in both amino acid side chains and protein backbones, resulting in protein fragmentation or protein–protein cross-linkages. Although all amino acids can be modified by ROS, cysteine, and methionine that are the most susceptible to oxidative changes due to high reaction susceptibility of the sulfur group in those amino acids. Oxidative modifications of proteins can change their physical and chemical properties, including conformation, structure, solubility, susceptibility to proteolysis, and enzyme activities. These modifications can be involved in the regulation of fresh meat quality and influence the processing properties of meat products. Oxidative stress occurs when the formation of oxidants exceeds the ability of antioxidant systems to remove the ROS in organisms. Increased levels of protein oxidation have been associated with various biological consequences, including diseases and aging, in humans and other animal species. The basic principles and products of protein oxidation and the implications of protein oxidation in food systems, especially in meat, are discussed in this review.     

不同包装方式下蛋白质氧化对鲜肉品质的影响研究进展

蛋白质氧化是活性氧或氧化应激的副产物引起蛋白质的共价修饰。蛋白质氧化的结果主要是引起氨基酸侧链基团的修饰、蛋白质肽链骨架的断裂以及蛋白质分子内和分子间的交联或聚集,从而改变蛋白质的分子结构与功能,最终导致鲜肉品质的变化。目前,鲜肉在市场上的主要包装方式有托盘包装、真空包装、真空贴体包装和气调包装4 种。不同包装方式在冷藏期间由于含氧量的不同引起蛋白质氧化程度不同,进而对鲜肉的品质产生重要影响。本文对市场上常用的鲜肉包装方式、蛋白质氧化的定义和机理以及不同包装方式下蛋白质氧化对鲜肉品质的影响进行综述。     

Reducing lipid peroxidation for improving colour stability of beef and lamb: on-farm considerations

Meat colour and lipid stability are important sensory properties. Myoglobin oxidation is correlated with lipid oxidation, and one can exacerbate the occurrence of the other. Approaches to reduce both oxidative processes could focus on minimising oxidising agents in meat. In on-farm practices, dietary supplementation of antioxidants is a useful approach for improving lipid stability and then meat colour stability, and further improvement could be a combination of using hydrophobic and hydrophilic antioxidants. Genetic variations in the endogenous antioxidant systems could be identified for the development of a breeding strategy to bring a long-term benefit to the meat industry. To have a better understanding of oxidative stress and oxidation of long chain unsaturated fatty acids in live animals, the isoprostanes could be measured as an effective marker in vivo.     

快速冷却对兔肉背最长肌肉品质的影响

为探讨快速冷却对兔肉食用品质的影响,选取24只獭兔进行屠宰,取背最长肌,按试验设计进行快速冷却和常规冷却处理后测定肉品质相关指标。结果表明：快速冷却(－12℃±1℃,30min;0～4℃储藏至24h)能加快兔肉温度下降速率,减缓pH值下降速率;使肉色泽改善,提高肉的保水性;成熟7d内显著降低肌肉脂肪氧化,但对兔肉的嫩度没有影响。     

Dietary corn germ containing phytic acid prevents pork meat lipid oxidation while maintaining normal animal growth performance

The effects of dietary defatted corn germ meal (DCGM) containing phytic acid (PA) on pig health during development and on its Longissimus dorsi m. (LD) lipid oxidative stability has been evaluated. Rations of DCGM were prepared at the level of substitution of 0%, 10%, 20% and 40% and offered to twenty four animals of Landrace x Large White crossbreds throughout 25 days before slaughtering. Animals were sacrificed at an average weight of 91.24 kg (±0.950) and samples for meat lipid oxidation analysis were taken after seven days under refrigeration at 3 °C. Animals fed with DCGM did not show any significant difference, in comparison to the control, in carcass characteristics, such as cold carcass weight, backfat depth, muscle depth, lean meat percentage and carcass dress yielding (p  0.05). Finally, no difference in meat proximate chemical composition was detected solely arising from lipid oxidation since LD from DCGM-treated pigs revealed an inhibition of 63.0%.     

Natural antioxidants against lipid–protein oxidative deterioration in meat and meat products: A review

Oxidation is a well-known non-microbial cause of quality loss in meat. Oxidative stress occurs due to uneven generation of free radicals reactive oxygen species (ROS) and reactive nitrogen species (RNS) which triggers oxidative and/or nitrosative stress and damage of macromolecules including the lipid and protein fractions. Failure of synthetic antioxidants to combat multiple health risks associated with this stress and maintenance of functional integrity of oxidised meat hitherto remains a challenge to the meat industry. A search for a viable alternative amidst the unexploited novel sources of natural antioxidants stands as a sustainable option for preserving the meat quality. In this paper, the potential use of bioactive compounds in medicinal plants is reviewed as phytoremedy against lipid–protein oxidation. Synergistic antimicrobial potentials of these natural antioxidants are also revealed against oxidative deterioration in meat and meat products and, for enhancing their functional properties.     

The restriction of grazing duration does not compromise lamb meat colour and oxidative stability

Over 72 days, 33 lambs were fed: concentrates in stall (S), grass at pasture for 8 hours (8 h), or grass at pasture for 4 hours in the afternoon (4h-PM). The 4h-PM treatment did not affect the carcass yield compared to the 8h treatment. Meat colour development after blooming was unaffected by the treatments. The 4 h-PM treatment increased the proportion of polyunsaturated fatty acids (PUFA; P<0.0005) and of the highly peroxidizable fatty acids (HP-PUFA; P<0.001) in meat compared to the 8h treatment. The S treatment increased lipid oxidation (higher TBARS values) and impaired colour stability (higher H* values) of meat over storage compared to the 8h and 4 h-PM treatments (P<0.0005 and P=0.003, respectively). No difference in meat oxidative stability was found between the 8h and the 4h-PM treatments. In conclusion, growing lambs can tolerate a restriction of grazing duration without detrimental effects on performances and meat oxidative stability.     

钙盐对肉与肉制品肉色的影响及其机理研究进展

在肉类工业中,钙盐常用于改善生鲜肉的嫩度,或者作为肉制品营养强化剂或低钠肉制品的部分替代盐类应用在肉制品中。但研究发现,钙盐处理在以上应用过程中容易导致肉色的劣变。然而,在目前关于钙盐与肉色关系的研究中,有许多结论存在争议,这可能与钙盐种类、添加剂量、加工方法以及诸多环境因素有关。因此,为进一步明确钙盐对肉色影响的机制和当前的研究进展,本文从钙盐与脂质氧化和高铁肌红蛋白还原活性的关系等方面探讨了钙盐影响肉色的可能机制,并对近年来钙盐对肉与肉制品肉色和肉色稳定性影响的研究进展进行了概述,以期为未来钙盐在肉类工业中的合理应用提供借鉴。     

Effect of different dietary levels of natural-source vitamin E in grow-finish pigs on pork quality and shelf life

Improving pork quality and shelf life is important in today’s swine industry because higher levels of DDGS are incorporated into pig diets. Relatively high level of poly-unsaturated fatty acids (PUFA) in DDGS may increase pork susceptibility to lipid oxidation and thus reduce pork shelf life. Antioxidants such as vitamin E may delay the onset of pork lipid oxidation when used as an ingredient in the diet. This experiment examined carcass characteristics, meat quality, shelf life, and color stability in pork from pigs (n = 150) fed five levels of a natural vitamin E (Nova-E) and one level of synthetic vitamin E. Natural vitamin E and synthetic vitamin E had no effect on carcass characteristics or meat quality. Increasing dietary natural vitamin E from 10 to 200 mg/kg decreased lipid oxidation. Lipid oxidation of pork chops and ground pork was similar between pigs fed 40 mg/kg and higher levels of natural vitamin E, indicating no additional benefits from supplementing beyond 40 mg/kg natural vitamin E. Supplementing 200 mg/kg synthetic vitamin E decreased pork lipid oxidation when compared to supplementing 10 mg/kg natural vitamin E. High levels of natural vitamin E or synthetic vitamin E, however, did not prevent discoloration of loin chops. These data indicate that natural vitamin E was effective to help reduce lipid oxidation and the effective minimal level of dietary supplementation appeared to be 40 mg/kg.