Determination of soybean proteins in commercial heat-processed meat products prepared with chicken,beef or complex mixtures of meats from different species

The addition of foreign proteins (mainly soybean proteins and milk proteins) to heat-processed meat products is a common practice. This work approaches the determination of additions of soybean proteins in heat-processed meat products prepared with chicken meat, beef meat, and complex mixtures of meats from different species (chicken, pork, beef, and turkey) by perfusion reversed-phase high-performance liquid chromatography. The applied method was previously developed for the determination of soybean proteins in pork and turkey meat products but it has never been tested for the determination of soybean proteins in other heat-processed meat products containing other kinds of meats. This paper demonstrates the validity of this method for the detection of soybean proteins in heat-processed meat products containing different varieties of meats and even in the presence of other foreign proteins such as milk proteins. The specificity and existence of matrix interferences have been checked for these samples and accuracy has been evaluated by the comparison of the soybean protein contents determined by the proposed method and the official ELISA method.     

Species-specific expression of various proteins in meat tissue: Proteomic analysis of raw and cooked meat and meat products made from beef,pork and selected poultry species

The aim was to search for proteins differentiating the six species (cattle, pig, chicken, turkey, duck and goose) and relatively stable during the meat aging and only slightly degraded in ready-made products. The two-dimensional electrophoresis was used for analysis of the protein profiles from raw meat and frankfurters and sausages (15 products). The observed species-specific differences in protein expression in raw meat were retained in processed products after finishing the entire technological process. Regulatory proteins, metabolic enzymes, some myofibrillar and blood plasma proteins were identified, which were characterised by the electrophoretic mobility specific to the given species. Large differences in the primary structure were observed in serum albumin, apolipoprotein B, HSP27, H-FABP, ATP synthase, cytochrome bc-1 subunit 1 and alpha-ETF. Some of these proteins have potential to be used as markers in authentication of meat products.     

Proteomic approach for the detection of chicken mechanically recovered meat

Mechanically recovered meat is cheaper than raw meat and thus has been incorporated into many meat-derived products. EU regulations exclude mechanically recovered meat from the definition of meat; as a consequence analytical procedures are needed to differentiate it from hand-deboned meat. The present pilot study has utilized a proteomic approach to find potential markers for the detection of chicken mechanically recovered meat. Intact proteins were extracted from raw meat and then analyzed with OFF-GEL electrophoresis followed by SDS-PAGE and identification of potential markers by nano-LC-MS/MS. It was shown that it is possible to extract, separate and identify key proteins from processed meat material. Potential chicken mechanically recovered meat markers--hemoglobin subunits and those similar to myosin-binding protein C were also identified.     

Identification of meat species by TaqMan-based real-time PCR assay

In this study, a convenient, sensitive and specific real-time PCR assay was described for the species identification and their quantification in raw and cooked meat products. Specific primers and TaqMan probes were designed on the mitochondrial ND2, ND5 and ATP 6-8 genes for donkey, pork and horse, respectively, and the performance of the method was tested. In the results, no cross-reaction was observed between the donkey and pork species specific primer-probe systems and non-target species (bovine, ovine, chicken and turkey). Only one cross reaction was observed between the horse species specific primer-probe set and 100 ng pork DNA at the ct 33.01 level (corresponding to 0.01 ng horse DNA). The real-time quantitative assay used in this study allowed the detection of as little as 0.0001 ng template DNA from pure meat for each species investigated and experimental meat mixtures. In conclusion, it can be suggested that the TaqMan probe assay used in this research might be a rapid and sensitive method for the routine meat species identifications studies in raw or cooked meat products.     

Partial purification of horse-specific soluble muscle proteins by immunoadsorption chromatography

Immunoadsorption chromatography has been used to isolate horse-specific soluble muscle proteins from crude horse protein extracts. Horse-specific polyclonal antibodies against soluble horse muscle proteins immobilised on a Protein A-Sepharose CL-4B matrix were used to adsorb the corresponding antigens. Analysis of the crude soluble horse muscle proteins by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) showed the existence of 20 protein subunits in the gel. SDS-PAGE of the proteins recovered by affinity chromatography showed nine protein subunits, three of which were enriched after the immunopurification step. These affinity-recovered horse-specific soluble muscle proteins may be used as antigens in the development of monoclonal antibodies to detect and quantify horse meat in raw, unheated meat mixtures.     

Monoclonal Antibodies to Porcine Thermal-Stable Muscle Protein for Detection of Pork in Raw and Cooked Meats

Four hybridoma cell lines secreting monoclonal antibodies (MAbs) specific to porcine thermal-stable muscle proteins (TSMPs) were developed. The MAbs reacted with three protein bands (20.5, 22 and 24 kD) from raw pork extract; the protein band (24 kD) which was also present in cooked pork was identified as porcine-specific TSMP. Epitope analysis indicated four MAbs recognized same or closely located antigenic sites on the pork TSMP. The developed MAb-based indirect enzyme-linked immunosorbent assay (ELISA) enabled the detection of pork in raw and cooked heterogeneous meat mixtures as low as 10 g/kg. The curvilinear relations of second-degree polynomial (r² > 0.995) between pork concentrations and ELISA responses enabled quantifying degree of adulteration of pork in meat products.     

Utilization of structurized oilseed proteins in minced meat products

The effect of protein isolate mixtures of sunflower and soya bean seeds on the structural and mechanical properties and the biological value indicer of chopped meat products has been studied. The possibility of using the structurized oilseed proteins in chopped meat products at the rate of 30–50 per cent has been shown.     

Influence of sunflower flour on the extrusion behaviour of soya grits and the functional properties of the extrudates (Short communication)

Texturizing is the key to produce meat-like products from vegetable proteins; by application of texturized protein products it is possible to increase the substitution rate of meat in meat products, because such products have their own structure, and their addition will not cause such a structure loss as it is connected with addition of proteins as a powder. Thermoplastic extrusion is a relatively simple procedure to process flours to structurates [1, 2]. Our aim was to study the extrusion of mixtures of soybean and sunflower flours, because the amino acid compositions of the two proteins supplement each other.     

Protein and lipid oxidation in meat: A review with emphasis on high-pressure treatments

BackgroundHigh-pressure (HP) treatment is considered a food safety process that can stabilize meat by inactivating microorganisms. However, HP treatment can induce modifications of components, such as lipids and proteins, and favor their oxidation by promoting the formation of radicals. Oxidation is one of the most important factors in the non-microbial degradation of meat. Lipid oxidation has been extensively investigated in meat because the products of the reaction can readily react with proteins, leading to organoleptic modifications and the loss of nutritional value. In contrast, the interest in protein oxidation is more recent.Scope and approachThe objective of this work is to review the literature on the effect of HP treatment on lipid and protein oxidation in comparison with that of classical meat processing to identify a possible link between protein and lipid oxidation and the underlying mechanisms.Key findings and conclusionsMicroorganisms were efficiently inactivated after treatment at pressures above 400 MPa. This pressure seems to be critical for the initiation of lipid oxidation, which was probably related to the no hemic iron in the meat, rather than the hemic compounds. Lipid and protein oxidation are closely related, as shown by the observed pattern of each reaction, which depends on the type of meat, the treatment used, and the methods used to assess the reactions. As it was observed to be for cooked meat products, the impact of HP could be greater for meat products that underwent cold storage. Better control of the quality of meat products subjected to HP treatments requires that the entire process, extending from the raw product to its conservation and consumption, be considered.     

Survey of authenticity of meat species in food products subjected to different technological processes,by means of PCR-RFLP analysis

Polymerase chain reaction (PCR) coupled to restriction-fragment length polymorphism analysis (RFLP) was considered for exploring the incidence of incorrect labelling in food products containing one or more meat species. Universal primers CYT b1/CYT b2, which amplify a variable region of the mitochondrial cytochrome b of vertebrates, and endonucleases PalI, MboI, HinfI and AluI were used for this purpose. Fifty food products, nine of them raw or cured and the other 41 subjected to a variety of technological processes such as pre-cooking and freezing, cooking and smoking, dehydration or sterilisation, were investigated. Twenty of the 50 products declared mixtures of meat species on their labels. Fifteen (30%) of the 50 food samples investigated displayed an incorrect qualitative labelling. While this affected only one (11.1%) of the nine raw/cured products, 14 (34.2%) of the 41 products subjected to some type of heat-processing were not correctly labelled. The undeclared presence of turkey was the most frequent concern, since it was detected in seven food products. The complete absence of a declared species of high commercial value—such as beef or roe-deer—was observed in another four cases. The PCR-RFLP method used here proved to be a rapid and easy-to-perform two-step analytical approach to achieve qualitative meat species identification in raw and cooked food products containing one or more different species.     

Novel TaqMan real-time polymerase chain reaction assay for verifying the authenticity of meat and commercial meat products from game birds

Species-specific real-time polymerase chain reaction (PCR) assays using TaqMan probes have been developed for verifying the labeling of meat and commercial meat products from game birds, including quail, pheasant, partridge, guinea fowl, pigeon, Eurasian woodcock and song thrush. The method combines the use of species-specific primers and TaqMan probes that amplify small fragments (amplicons <150 base pairs) of the mitochondrial 12S rRNA gene, and an endogenous control primer pair that amplifies a 141-bp fragment of the nuclear 18S rRNA gene from eukaryotic DNA. Analysis of experimental raw and heat-treated binary mixtures as well as of commercial meat products from the target species demonstrated the suitability of the assay for the detection of the target DNAs.     

Modification of technological properties of fish protein concentrates

Fish protein concentrates are mixtures of cross‐linked and aggregated molecules of different muscle proteins. The final conformation of the components of the mixtures is formed as a result of procedures applied to convert the raw material into a product of desirable and stable sensory properties, containing less than 0.1% of lipids. To achieve this end usually extraction with hot organic solvents, mainly isopropyl alcohol and 1,2‐dichloroethane, followed by air drying are employed. These conditions bring about denaturation of many of the proteins followed by aggregation of the molecules due to the interaction of reactive functional groups in extended polypeptide chains. In the final product a large proportion of hydrophobic groups is exposed to the solvent and the proteins exhibit an extremely low water affinity. Such concentrates, although valuable as protein supplements, have only limited suitability as active components of various processed foods, as they have poor technological value. They are insoluble or have a very low water dispersibility and swelling ability, do not form gels after heating, or have any significant fat‐emulsifying capacity. Changing the dissociation or number of ionic groups of the molecules prior to extraction, e.g., by acidifying or acylating, can partially reduce the denaturing effect of heat and organic solvents and thus improve the functional properties of the product. An upgrading of the quality of concentrates produced by hot extraction can be achieved by partial enzymatic or chemical deaggregation, hydrolysis followed by the plastein reaction, or formation of suitable derivatives. The best results have been obtained by partial hydrolysis of acylated proteins or precipitation of the aggregated products using sodium hexametaphosphate. The functional properties of such products are comparable to those of vegetable protein isolates used as meat extenders. Various protein products of high technological value can be also obtained by enzymatic hydrolysis of the raw material, followed by separation of the lipids without organic solvent extraction. Such products, however, have a distinct odor and flavor and must be stabilized because of residual lipids.     

Quantitation of Soy Protein in Frankfurters by Gel Electrophoresis

A modified Laemmli procedure was utilized to obtain gel electrophoretie resolution of protein components in soy and beef isolates and in processed meat products containing soy protein isolate (SPI). Height and area ratios of selected soy and beef components (α', α-subunits of β-conglycinin and actin) were calculated from densitometric scans and compared with similar ratios calculated for soy and beef mixtures of known composition. This method permitted the quantitation of soy protein (±0.14%) in raw and pasteurized frankfurters and should be applicable to other selected soy-containing meat products.     

Detection of chicken and turkey meat in meat mixtures by using real-time PCR assays

In this study, TaqMan-based real-time Polymerase Chain Reaction (PCR) techniques were developed for the detection of chicken and turkey meat in raw and heat-treated meat mixtures. Primers and TaqMan probe sets were designed to amplify 86 bp and 136 bp fragments for the chicken and turkey species, respectively, on the mitochondrial NADH dehydrogenase subunit 2 gene. In the results, it was possible to detect each species at the level of 0.1 pg template DNA with the TaqMan probe technique without any cross-reactivity with nontarget species (bovine, ovine, donkey, pork, and horse) while the detection level was 1 pg template DNA using conventional PCR. The TaqMan probe assays used in this study allowed the detection of as little as 0.001% level of both species in the experimental meat mixtures, prepared by mixing chicken and turkey meat with beef at different levels (0.001% to 10%). In conclusion, TaqMan probe assays developed in this research are promising tools in the specific identification and sensitive quantification of meat species even in the case of heat-treated meat products, and suitable for a rapid, automated, and routine analysis.     

植物蛋白肉的原料开发、加工工艺与质构营养特性研究进展

植物蛋白肉以植物蛋白质为主要原料,通过重塑蛋白质的解离聚合行为形成类肉纤维结构,同时添加油脂、色素、粘合剂等非动物来源食品配料,加工定制出接近真实动物肉的形态色泽与风味口感.由于能够有效解决肉类供应不足问题,食品安全性高、生产方式绿色可持续,植物蛋白肉作为肉类替代食品发展迅猛,受到食品工业的广泛关注.本文将对植物蛋白肉...     

PCR identification of beef, sheep, goat, and pork in raw and heat-treated meat mixtures

A PCR assay has been developed for the specific and qualitative detection of pork (Sus scrofa domesticus), beef (Bos taurus), sheep (Ovis aries), and goat (Capra hircus) in raw and heat-treated meat mixtures. A forward common primer was designed on a conserved DNA sequence in the mitochondrial 12S ribosomal RNA gene (rRNA), and reverse primers were designed to hybridize on species-specific DNA sequences of each species considered. The different sizes of the species-specific amplicons, separated by agarose gel electrophoresis, allowed clear species identification. Analysis of experimental meat mixtures demonstrated that the detection limit of the assay was 1% (wt/wt) for each species analyzed. This assay can be useful for the accurate identification of these species, avoiding mislabeling or fraudulent species substitution in meat mixtures.     

冷等离子体对肉蛋白的影响及其在肉品保藏加工中的应用研究进展

冷等离子体主要通过产生的活性氮或活性氧对肉品杀菌并降低内源酶活性,从而达到肉品保藏的目的,活性氮的存在使其可作为肉制品中亚硝酸盐的替代物,但活性粒子对肉品成分尤其是对蛋白质和脂肪的影响不容忽视,过度氧化最终导致肉品品质劣变。本文综述国内外关于冷等离子体技术在肉蛋白及肉品中的作用形式,及其对肉蛋白中肌原纤维蛋白和肌红蛋白结构和功能的调控作用及相关机制,并概述冷等离子体技术在肉品保藏加工领域的应用研究现状,以期为冷等离子体技术在肉品工业中的广泛应用提供参考。     

IDENTIFICATION OF POULTRY MEAT FROM PORK AND BEEF ON THE BASIS OF THE TITIN PEVK REGION USING PCR

The possibility of distinguishing three kinds of meat species (chicken, porcine and bovine) alone or in two-component meat mixtures was investigated using the polymerase chain reaction. The contribution of each component in the meat mixtures ranged from 1 to 100%. The identification of meat was performed on the basis of the sequence coding the PEVK region of titin and by employing polymerase chain reaction. DNA was isolated from raw, fresh and chilled meat. The data presented in this study suggest that it is possible to detect chicken meat, pork and beef in meat mixtures on the basis of PEVK region by using PCR.

PRACTICAL APPLICATIONS

The polymerase chain reaction (PCR) is a precise and quick technique that has many practical applications. Using PCR with primer sets designed on the basis of the PEVK region present in titin can be a convenient tool for species identification, especially for chicken meat mixed with pork and beef meat in two-component meat mixtures. Reliable and sensitive methods for species differentiation can give consumers confidence about authentic meat product composition.     

植物蛋白肉的加工及品质特性研究进展

由于动物蛋白需求增加导致的环境压力增大、供给压力增大以及人体健康等问题,近年来植物蛋白肉受到国内外研究人员的广泛关注,成为食品行业的新风口。植物蛋白肉是以植物原料或其制品为蛋白质、脂肪的主要来源加工制成的具有与动物蛋白的质构、风味、形态等品质特征类似的替代肉制品。目前国内外已有多种加工方式来制备生产植物蛋白肉,但植物蛋白肉的品质与动物蛋白相比仍具有一定的差距,因此探究植物蛋白肉品质特性以及提升方法刻不容缓。本文总结了植物蛋白肉生产原料、加工技术及加工中的化学变化;阐述了植物蛋白肉的结构特性、质构及感官特性、营养特性等品质特性及分析评价方法;最后提出了改善植物蛋白肉品质的研究方向,以期为植物蛋白肉产品品质提档升级提供参考。     

Detection of mechanically recovered meat and head meat from cattle in ground beef mixtures by multivariate analysis of isoelectric focusing protein profiles

The present work investigates the possibility of constructing a multivariate calibration model for predicting the composition of ground beef with respect to different meat quality types, based on intensity profiles from isoelectric focusing of water-soluble proteins. Beef mixtures containing various amounts of mechanically recovered meat, head meat and production meat from beef, were analysed by isoelectric focusing in immobilised pH-gradients. The gels were photographed and the images transferred to a digital format. By simple image processing procedures, background colour was virtually eliminated and signal strength was improved to a considerable degree. Multivariate analysis of protein profiles from the gels gave models explaining 75 to 90% of variance in sample composition. Manually deboned meat was explained to the highest degree, and with a precision of 7%. Two different qualities of mechanically recovered meat could be detected even when treated as one category. The present approach needs further refinement, but seems applicable for detecting intentional substitution of high quality meat products with low-price raw materials. One advantage of the approach is that evaluation of samples is not dependent on specific knowledge on the individual components to be analysed, so that such analytical methods are relatively easy to implement in any standard laboratory.