Effects of protein oxidation on the texture and water-holding of meat: a review

Abstract

Protein oxidation readily occurs in postmortem muscle during storage and processing. Over the past decade new analytical methods have been developed and new aspects of protein oxidation in meat have been studied, such as the reaction mechanism, and impacts on eating quality and nutritional value. It is now evident that amino acid side chains in myofibrillar proteins undergoes modifications due to oxidative stress. In turn this will lead to formation of new protein-protein cross-links in structural proteins, however, also the overall level of fixed-charge groups attached to the peptide backbones is modified. Meat texture and water-holding are important quality attributes and they are affected by the oxidation of structural proteins. Different mechanisms have been suggested to explain the oxidation-induced quality changes, focusing mainly on reduced proteolysis and formation of cross-links. This review explores the current understanding of protein oxidation in fresh meat in relation to texture and water-holding. The consequences of protein oxidation at molecular level in relation to oxidation-induced cross-linking and changes in net charges of myofibrillar proteins, and the impacts on texture and water-holding are discussed.     

Mechanisms of meat batter stabilization: a review.

Comminuted meat products are a complex mixture of muscle tissue, solubilized proteins, fat, salt, and water. The two theories that have been presented to explain meat batters stabilization are reviewed. The emulsion theory explains stabilization by the formation of a protein film around fat globules, whereas the physical entrapment theory emphasizes the role of the protein matrix in holding the fat in place during chopping and subsequent heating. However, some aspects of stabilization cannot be explained adequately by either one of these theories. In this article the role of meat proteins, aqueous phase, and lipid phase are examined in light of past and recent research findings.     

Texture,colour and sensory evaluation of a conventionally and ohmically cooked meat emulsion batter

Samples of meat emulsion batter were steam or ohmically cooked (at voltage densities ranging from 3 to 7 V cm^?1) to standardized cook values (C_s) or to target end point temperatures (EPT). Higher ohmic voltage densities produced faster heating rates. Texture profile analysis (TPA) of ohmic and steam‐cooked frankfurters showed no significant difference (p ≥ 0.05) in any of the attributes assessed with the exception of springiness, which was significantly lower (p < 0.05) in ohmically cooked samples heated to similar C_s values, although this trend was less pronounced in samples cooked to similar EPT. Instrumental colour evaluations revealed that ohmically cooked samples (cooked both to similar C_s and EPT) differed from steam‐cooked in both a* and hue angle values (especially at 5–7 V cm^?1 (p < 0.05)). Although instrumental measurements revealed differences in selected texture and colour attributes, panellists were not able to distinguish between steam and similar EPT ohmically cooked samples (p < 0.05). Thus while subtle differences may exist in the eating quality of ohmic and steam‐cooked emulsions, these differences are unlikely to be of an order of magnitude to affect consumer acceptance of ohmically cooked meat emulsion products. Copyright © 2004 Society of Chemical Industry     

Effect of bamboo salt on the physicochemical properties of meat emulsion systems

This study was conducted to determine the effects of various bamboo salts on meat batter. To accomplish this, three different batters were prepared and compared: CON, which was prepared with NaCl, BS-2, which was prepared with bamboo salt that was baked twice, BS-9, which was prepared with bamboo salt that was baked nine times. The pH of both the uncooked and cooked BS-2 and BS-9 was higher than that of the CON (P < 0.05). The emulsion stability, cooking yield, water holding capacity (WHC) and apparent viscosity of BS-2 and BS-9 were higher than those of CON. The correlation coefficient between the viscosity value and WHC was high and positive (R² = 0.672). The hardness of all treatments was significantly increased with increased cooking temperature (P < 0.05). The hardness, gumminess and chewiness of CON were higher than that of BS-9 and BS-2. The overall acceptability score between CON and BS-9 was significantly different (P < 0.05). The bamboo salts effectively improved the physicochemical properties of the meat batter.     

Functional effects of lupin proteins in comminuted meat and emulsion gels

The mechanical and textural properties of gel network resulting by heating at 90 °C of comminuted meat systems, containing lupin seed protein isolate at a relatively low concentration (2%), were studied in an attempt to establish the role of the lupin proteins in the gel structure network development. These results are supported with data from SDS–PAGE analysis of the adsorbed protein at the fat particle surface of the system. The findings are considered in terms of lupin protein involvement in interactions, either at the fat particle surface, or within isolated pockets of high lupin protein content.     

鹰嘴豆分离蛋白对减盐猪肉糜凝胶品质的影响

为探究鹰嘴豆分离蛋白(chickpea protein isolate, CPI)不同添加量对2种盐含量(质量分数1.4%和2%)猪肉糜凝胶品质的影响,将猪瘦肉与猪背膘斩拌成肉糜,分别设置不同盐含量和鹰嘴豆分离蛋白的处理组并加热制成凝胶。测定猪肉糜凝胶的色泽、乳化稳定性、质构、水分分布和流变特性。结果表明,在不添加鹰嘴豆分离蛋白的条件下,1.4%食盐质量分数的猪肉糜凝胶的汁液流失和硬度值显著高于2%食盐浓度的猪肉糜凝胶;相同食盐浓度条件下,随着CPI添加量的增加,猪肉糜凝胶的a^*值、b^*值、硬度、弹性、咀嚼性以及不易流动水比例均显著增加(P<0.05),动态流变储能模量G′值升高,汁液流失率显著降低(P<0.05),并在CPI添加量为1.2%时达到最大值或最小值;在相同CPI添加量条件下,1.4%食盐1.2%CPI的猪肉糜凝胶的储能模量G′值高于2%食盐1.2%CPI的猪肉糜凝胶,且2组凝胶的不易流动水比例、乳化稳定性、质构特性无显著差异(P>0.05)。综上,鹰嘴豆分离蛋白的添加能够在降低食盐用量的同时提升猪肉糜的凝胶品质...     

Application of microbial transglutaminase in meat foods: A review

Microbial transglutaminase (MTG) is an enzyme isolated from a variant of Streptomyces mobaraensis that forms covalent cross-links between protein molecules. Studies are being conducted since last two decades on utilization of MTG in meat foods to improve their characteristics, such as gelation, water-binding, emulsion stability, purge loss, cooking loss, etc. MTG is one of the important topics of interest in meat processing industry due to its advantages in practical utilization and commercial exploitation. This review will discuss about the overall applications of MTG in manipulating the functional properties of meat and meat products by means of various processes such as restructuring, value addition, etc.     

Physico chemical,microstructural and sensory characteristics of low‐fat meat emulsion containing aloe gel as potential fat replacer

In this study, a possible use of aloe gel (AG) as a potential fat replacer in the manufacture of low‐fat meat emulsion was investigated. The low‐fat meat emulsions with added AG and vegetable oil (VO) in different proportions [AG7.5 (7.5% AG + 7.5% VO); AG5 (5% AG + 10% VO); AG2.5 (2.5% AG + 12.5% VO)] were compared with full‐fat meat emulsion [Control (15% VO only)]. A substantial fat reduction (P < 0.05) up to 50% as compared to full‐fat control meat emulsion was recorded without compromising other sensory attributes of meat emulsion. Microstructural properties as studied by scanning electron microscopy indicated more homogenous regular emulsion matrix with fewer cracks and more regular shaped oil droplets in AG‐added samples than the control samples.     

Analysis of soyabean proteins in meat products: a review

The use of soyabean proteins as meat extenders has spread significantly due to the interesting nutritional and functional properties that are present in soyabean proteins. Together with these, health and economical reasons are the major causes for the addition of soyabean proteins to meat products. Nevertheless, despite the good properties associated to soyabean proteins, there are many countries in which the addition of these proteins is forbidden or in which the addition of soyabean proteins is allowed up to a certain extent. Thus, the need of analytical methods enabling the detection of added soyabean proteins in meat products is obvious. Microscopic, electrophoretic, immunologic, and chromatographic methods are the most widely used for this purpose. However, the detection of soyabean proteins in meat products presents difficulties related to the composition (meat species, meat quality, soyabean protein source, presence of other non-meat proteins, etc.) and the processing of the meat products, and, although these analytical methods have tried to overcome all these difficulties, there is still not a method enabling quantitative assessment of soyabean proteins in all kinds of meat products.     

河南省居民肉及肉制品中铜摄入水平及其风险评估

目的以河南省肉及肉制品中铜为例,演示采用简单分布评估方法,评价河南省居民肉及肉制品饮食中铜摄入情况及其潜在的健康风险。方法 2014—2015年在河南省16个省辖市随机采集肉及肉制品309份,按照食品中铜测定的原子吸收光谱法标准操作程序进行检测,结合河南省2010—2012年开展的居民营养与健康状况监测中肉及肉制品的消费量数据,采用简单分布模型(确定性评估)方法,借鉴文献发表的肉及肉制品对膳食中铜的贡献率,计算河南省不同年龄组人群全膳食中铜摄入水平及其潜在的健康风险。结果肉及肉制品中铜的平均含量为0.556 mg/100 g,中位数为0.060 mg/100 g,不同肉及肉制品中铜平均含量最高为内脏(1.561 mg/100 g),铜平均含量最低的为猪肉(0.068 mg/100 g)。河南省居民每天通过进食肉及肉制品的铜平均摄入量为0.046 mg/d,高端(P95)摄入量为0.144 mg/d。利用文献报道的肉及肉制品贡献率外推全膳食中铜摄入量后发现,河南省居民全膳食中铜的平均和P95摄入量分别为0.638和1.977 mg/d。个体评估结果显示,全人群铜摄入量处于推荐摄入量(RNI)与可耐受最高摄入量(UL)之间的个体比例为21.12%(801/3 792),处于EAR和RNI之间的个体比例为8.10%(307/3 792),而低于平均需要量(EAR)、大于UL的人群比例分别为69.75%(2 645/3 792)和1.03%(39/3 792)。结论河南省全人群膳食中铜摄入量缺乏的风险较高,铜过量的风险较低。     

Conjugated linoleic acid in meat and meat products: A review

Conjugated linoleic acid (CLA) consists of a group of geometric and positional isomers of linoleic acid to which anticancerogenic, antidiabetic, and antiatherogenic effects, as well as effects on immune system, bone metabolism, and body composition are attributed. CLA is found predominantly in milk and meat of ruminants due to the importance of rumen micro-organism in the formation of CLA and its precursors. This review attempts to give an overview of the available data on intramuscular CLA concentrations in meat and meat products originating from different animal species. The factors influencing these concentrations are discussed and the estimated human daily intakes as well as the percentage provided by meat are reported.     

食品添加剂与肉制品加工

食品添加剂是肉制品行业加工中非常重要的加工助剂,新版GB 2760-2007非常明确的列出食品添加剂的功能、添加量、使用范围等,本文根据实践经验对食品添加剂的使用和功能认识方面所遇到的一些问题作出阐述.     

Irradiation effects on meat flavor: A review

Irradiating fresh meat, even at low doses, can result in off-odors and flavors which have been described as rotten egg, bloody, fishy, barbecued corn, burnt, sulfur, metallic, alcohol or acetic acid. The odors vary with the type of meat, temperature during irradiation, oxygen exposure during and/or after the irradiation process, packaging and presence of antioxidative substances. Irradiation can induce formation of isooctane-soluble carbonyl compounds in the lipid fraction and low molecular weight, acid-soluble carbonyls in the protein fraction of meat. Increasing irradiation dose increases these compounds however, cooking reduces them. Among the volatile components, 1-heptene and 1-nonene are influenced most by irradiation dose, and aldehydes (propanal, pentanal, hexanal) are influenced most by packaging type (aerobic vs vacuum). Sulfur-containing volatiles formed from sulfur-containing compounds (primarily amino acids) also contribute to irradiation odor. Dimethyltrisulfide is one of the most potent off-odor compounds, contributing fishy, putrid odors, followed by bismethylthiomethane (sulfurous). Reducing the temperature during the irradiation process reduces the effects on odor/flavor because free radical generation and dispersion are reduced. Ultimately, radiolysis of water into free radical species (OH,H, H(3)0(+), e(aq)(-)) may be the initiators of both lipid oxidation breakdown products and sulfur-containing volatiles responsible for irradiation odor. Methods to decrease the detrimental effects of irradiation include oxygen exclusion (vacuum packaging), replacement with inert gases (nitrogen), addition of protective agents (antioxidants), and post-irradiation storage to allow flavor to return to near-normal levels (re-packaging or double packaging in oxygen permeable film).     

糊的组成成分对挂糊油炸肉制品品质影响的研究进展

挂糊油炸肉制品作为一类重要的传统食品,具有色泽金黄、外壳酥脆等特点,深受消费者的喜爱。随着人们消费水平的提高和健康意识的增强,具有低吸油率和高食用品质(外脆里嫩)的油炸制品引起了科研人员的广泛关注。糊的组成、油炸工艺条件、油炸用油等均会影响挂糊油炸肉制品的品质。其中,糊的组成成分是重要的影响因素。通过查阅国内外大量文献,详述了淀粉、蛋白质、食用胶等糊的组成成分对挂糊油炸肉制品品质影响的研究进展,可为油炸食品的原料选择提供一定的科学依据,从而利于挂糊油炸肉制品的工业化生产。      

Ultrasound applications in poultry meat processing: A systematic review

Ultrasound (US) is classified as a nonthermal treatment and it is used in food processing at a frequency range between 20 kHz and 1 MHz. Cavitation bubbles occur when the US strength is high enough to generate rarefaction that exceeds the intermolecular attraction forces in the medium. Currently, US is widely used in meat industries to enhance procedures, such as meat tenderization, emulsification mass transfer, marination, freezing, homogenization, crystallization, drying, and microorganism inactivation. In addition, combining ultrasonic energy with a sanitizing agent has a synergistic effect on microbial reduction. When poultry meat is treated using US, the expected quality is often better than the traditional methods, such as sanitization and freezing. US can be considered as a novel green technology for tenderizing and decontamination of poultry meat since both Escherichia coli and Salmonella are sensible to US. US improves the physical and chemical properties of meat proteins and can lead to a decrease in the α-helix in intramuscular protease complex in addition to a reduction in the viscosity coefficients. Therefore, ultrasonic treatment can be applied to enhance the textural properties of chicken meat. US can also be used to improve the drying rate when used under vacuum, compared with other traditional techniques. This review focuses on the potential of US applications in the management of poultry industries as the demand for good quality meat proteins is increasing worldwide.     

Optimization of replacing pork back fat with grape seed oil and rice bran fiber for reduced-fat meat emulsion systems

The effects of reducing pork fat levels from 30% to 20% and partially substituting the pork fat with a mix of grape seed oil (0%, 5%, 10% and 15%) and 2% rice bran fiber were investigated based on chemical composition, cooking characteristics, physicochemical and textural properties, and viscosity of reduced-fat meat batters. For reduced-fat meat batters containing grape seed oil and rice bran fiber the moisture and ash contents, uncooked and cooked pH values, yellowness, cohesiveness, gumminess, chewiness, and sarcoplasmic protein solubility were higher than in the control samples. The reduced-fat samples with increasing grape seed oil concentrations had lower cooking loss, emulsion stability, and apparent viscosity. The incorporation of grape seed oil and rice bran fiber successfully reduced the animal fat content in the final products while improving other characteristics.     

Flavor challenges in extruded plant-based meat alternatives: A review

Demand for plant-based meat alternatives has increased in recent years due to concerns about health, ethics, the environment, and animal welfare. Nevertheless, the market share of plant-based meat alternatives must increase significantly if they are to support sustainable food production and consumption. Flavor is an important limiting factor of the acceptability and marketability of plant-based meat alternatives. Undesirable chemosensory perceptions, such as a beany flavor, bitter taste, and astringency, are often associated with plant proteins and products that use them. This study reviewed 276 articles to answer the following five research questions: (1) What are the volatile and nonvolatile compounds responsible for off-flavors? (2) What are the mechanisms by which these flavor compounds are generated? (3) What is the influence of thermal extrusion cooking (the primary structuring technique to transform plant proteins into fibrous products that resemble meat in texture) on the flavor characteristics of plant proteins? (4) What techniques are used in measuring the flavor properties of plant-based proteins and products? (5) What strategies can be used to reduce off-flavors and improve the sensory appeal of plant-based meat alternatives? This article comprehensively discusses, for the first time, the flavor issues of plant-based meat alternatives and the technologies available to improve flavor and, ultimately, acceptability.     

高静压对添加酪朊酸钠鸡肉糜制品特性及其微观结构的影响

在肉制品加工中运用高静压技术对其改性将得到发展。研究侧重在50～600MPa和5～40min范围内单因素考察添加1.5%酪朊酸钠鸡肉糜制品保水性、质构、凝胶强度、色泽特性的影响,并从微观结构上分析其作用机理。结果表明:与未受压的对照样比较,200～500MPa和10～30min都能显著增强其保水特性(p<0.01),过低压力50MPa和过高压力600MPa有明显降低保水性现象(p<0.01);制品质构特性(硬度、咀嚼性)随着压力增大而增大;凝胶强度也同样随着压力增加而增加,但在600MPa出现明显劣化(p<0.01),从侧面反映了保水性变化特点;制品色泽(白度、彩度)基本上随着压力增大和时间延续均分别逐渐增大和下降;而保压时间对鸡肉糜制品的保水性、质构与凝胶强度的影响相对有限。综合分析,300MPa、20min的高静压条件处理可获得较高出品率、较好质构特性和色泽的添加酪朊酸钠鸡肉糜制品。     

Authentic sheep meat in the European Union: Factors influencing and validating its unique meat quality

Authentic meat products are gaining attention through their unique quality characteristics linked to their origin. Various factors are known to influence the quality of fresh meat. This review describes the different Protected Designation of Origin (PDO) and Protected Geographical Indication (PGI) lamb types and discusses the factors which influences its unique sensory and chemical characteristics. Flavour, aroma, texture and colour play an integral part in the sensory quality of denomination of origin fresh meat products. For authentic fresh sheep meat the sensory (as well as chemical) quality is largely influenced by diet followed by breed, age and gender. However, diet forms the link with the geographical area of origin, which together with the traditional production system and sheep breeds used, lends the product its authentic nature. This review shows how diet linked to origin can affect the quality of the meat and furthermore how other factors such as breed can also have an effect. Research relating to the authentic lamb types were evaluated and the shortcomings highlighted in order to assist with the development of PDO and PGI specifications in the future. © 2016 Society of Chemical Industry