Effect of high pressure treatment on the color of fresh and processed meats: A review

High pressure (HP) treatment often results in discoloration of beef, lamb, pork, and poultry. The degree of color changes depends on the physical and chemical state of the meat, especially myoglobin, and the atmospheric conditions during and after pressurization. A decreased redness is attributed to a large degree to the oxidation of the bright red oxymyoglobin or the purplish deoxymyoglobin into the brownish metmyoglobin, as well as to the denaturation of myoglobin. Surely, the high myoglobin content makes beef more exposed to this discoloration compared to the white chicken meat. In addition, HP treatment causes denaturation of myofibrillar proteins followed by aggregation, consequently, changing the surface reflectance and increasing lightness. Other intrinsic and extrinsic factors may affect the pressure-induced color changes positively or negatively. In this review, the pressure-induced color changes in meat are discussed in relation to modification of the myoglobin molecule, changes in the meat microstructure, and the impact of the presence of different chemical compounds and physical conditions during processing.     

Consumer preferences for pork chops with different levels of intramuscular fat

Pork chops with two different levels of intramuscular fat were distributed to consumers in the Dublin area for an in-home evaluation. Only regular pork consumers participated. The objective was to find out whether consumers perceived differences in the appearance and eating quality of the chops. Although an increase in the level of intramuscular fat may have a negative effect on appearance and ultimate purchase, consumers were no more likely to prefer the lower or the higher levels of intramuscular fat. It was also found that consumer ratings of the chops were not different for the important eating attributes of juicines, tenderness, and flavour. It was concluded that there would be no benefit in increasing the level of intramuscular fat to the upper limit available on the Dublin market, since consumer satisfaction in that market would not be increased.     

Consumer preferences for new fermented food products that mix animal and plant protein sources

Consumers are being encouraged to increase the proportion of plant protein in their diets to enhance the sustainability of food systems. One approach is to develop plant-protein-rich foods that are acceptable to consumers. This study examined French people’s reactions to cheese alternatives—new fermented products that mixed animal and plant protein sources. We conducted experimental sessions with 240 French participants to assess their responses to three fermented products containing different percentages of yellow pea and cow’s milk. First, we asked the participants to blind-taste the three products and solicited hedonic scores of products. We then provided the participants with simple information about the products’ composition and asked them to taste and score the liking of the products a second time. We also asked consumers to estimate their willingness to pay (WTP) for each product before and after revealing additional information about the nutritional or environmental benefits of consuming pea-based foods. The product with the lowest percentage of pea and the highest percentage of milk received the highest hedonic scores, and WTP was correlated with the hedonic scores. The additional information about the nutritional and environmental benefits of pea-based foods led to significant increases in WTP for two of the fermented products, but not for the least preferred product, namely the one with the highest percentage of pea. This finding suggests that participant reactions to information depended on hedonic preferences.     

Chromatographic Methods for the Determination of Carbohydrates and Organic Acids in Foods of Animal Origin

Carbohydrates are ubiquitous and range from simple monosaccharides to large complex polysaccharides. Organic acids are compounds with acidic properties. Both occur naturally in many foods and in fermented products. Organic acids are usually derived from the hydrolysis of carbohydrates by microorganisms such as lactic acid bacteria. These bacteria convert carbohydrates into energy required for growth, since they are not equipped with the enzymes necessary for respiration and are unable to perform oxidative phosphorylation. Determination of carbohydrates and organic acids in foods of animal origin is important, since they contribute to flavor and texture. Their presence and proportions can affect the chemical and sensory characteristics of a food matrix and they can provide information on nutritional properties of food and the means to optimize selected technological processes. Furthermore, the levels of carbohydrate and organic acid are important to monitor bacterial growth and activity. Actually, these compounds can be quantified by several methods including high‐performance liquid chromatography (HPLC) and gas chromatography (GC). High‐performance liquid chromatography has been widely used to analyze carbohydrates and nonvolatile organic acids, while gas chromatography has been used to determine the volatile organic acids in complex matrices. This contribution provides an overview of chromatographic methods (HPLC and GC) used to analyze carbohydrates and organic acids in foods of animal origin.     

Analysis of Livestock Product Consumption Coastal Household in North Minahasa Regency

This study aims to analyze the effect of income on consumption of farm products. The research method that has been used is the survey method. Determination of sampled by purposive sampling, namely the coastal areas. Determination of the respondents were done by simple random sampling. Households that consume chicken eggs as much as 96.36 percent, chicken meat 88.18 percent and pork 75.45 percent. Regression analysis showed that consumption of chicken eggs, chicken meat and pork respectively partially influenced by household income. In conclusion, household income significantly affect the consumption of chicken eggs, chicken meat and pork in North Minahasa regency.     

Rapid multi-residue and multi-class qualitative screening for veterinary drugs in foods of animal origin by UHPLC-MS/MS

Multi-class UHPLC-MS/MS was developed for the analysis of more than 160 regulated or banned compounds of various classes: anthelmintics including benzimidazoles, avermectins and others; antibiotics including amphenicols, beta-lactams, macrolides, pyrimidines, quinolones, sulphonamides and tetracyclines; beta-agonists; corticosteroids; ionophores; nitroimidazoles; non-steroidal anti-inflammatory agents; steroids; and tranquillisers. Samples were extracted with acetonitrile, without any additional purification step, and analysed by using UHPLC-MS/MS. Validation was done in accordance with the guidelines laid down by European Commission Decision 2002/657/EC for qualitative screening methods. This simple method proved applicable to routine screening for residues in egg, honey, milk and muscle samples at half the maximum concentration permitted by the European Union for each drug. In most cases, the target value was set at 5?µg?kg^?1 for unauthorised compounds.     

螺旋输送转速对肉料绞切加工品质的影响

为了考察绞切加工过程中绞肉机螺旋输送转速对肉糜品质的影响情况,以肉糜的p H、挥发性盐基氮（TVB-N）、持水能力和色泽等指标为评价依据,对不同螺旋输送转速下的猪肉和牛肉肉料绞切加工品质进行了实验研究。研究结果表明,转速对肉糜p H和TVB-N值的影响不明显,肉糜的p H总体变化比较稳定,TVB-N值则呈缓慢上升趋势。螺旋输送转速不会对绞切加工的肉糜持水能力和色泽产生明显影响,对于同一类肉糜,不同转速下得到的样本水分质量损失随贮藏时间的变化趋势十分接近。综合分析表明,对于实验样机,转速为140 r/min时获取的猪肉糜加工品质最为理想,而对于牛肉的最佳驱动转速是160 r/min。      

A review of methodology for the analysis of pyrethrin and pyrethroid residues in food of animal origin

Pyrethrin and pyrethroid pesticides are commonly used in crop protection and animal health, to control pests. As a result, they can potentially transfer into food if good agricultural practice is not followed or even due to accidental contamination. The analysis of these compounds has been widely reported in crops and the environment. However, the analysis of pyrethrin and pyrethroids has not been reported frequently in foods of animal origin, particularly animal tissues. The focus of this review is to report on pyrethrin and pyrethroid analysis including key aspects such as chemistry, choice of target matrix, sample preparation, chemical analysis, legislation and method validation. This review shows that most methodologies for the analysis of these compounds are based on gas chromatography with the trend in recent years to move towards GC-MS or GC-MS/MS based platforms. This review shows that these compounds can also be satisfactorily analysed by LC-MS/MS, which can be advantageous because of shorter chromatographic run times. A wide range of sample preparation procedures have been applied in analytical methods and more complex protocols are required for GC applications, whereas more crudely prepared extracts can be analysed by LC-MS/MS. This review demonstrates that pyrethrin and pyrethroid residues should be included as analytes in multi-class analytical methods for pesticides and veterinary drug residues in animal derived foods.     

Consumers' preferences for beef in the Spanish region of Extremadura: a study using conjoint analysis

The study of consumers' preferences is of great interest in the beef sector, where the BSE crisis generated deep changes in the basic conditions of demand for meat and in the behaviour of consumers. Previous qualitative research showed that ‘price’, ‘origin’, ‘production system’ and ‘labelling’ were the main attributes affecting preferences for beef in Extremadura (SW Spain). The data were obtained by a survey carried out between February and April 2002 with a sample of 575 regular consumers of beef. Conjoint Analysis has been used to estimate the relative importance of those attributes and to determine the existence of consumer segments with similar preference profiles. Results show that the origin of the product is the most important attribute for the choice of beef, followed by quality labelling, production system and price. Three groups of consumers were identified through cluster analysis, according to their preferences for beef. Copyright © 2005 Society of Chemical Industry     

肉及肉制品中彩虹色斑点现象的调查分析

彩虹色斑点是近年来发现存在于肉及肉制品中的一种非正常颜色。对我国几家大型屠宰场的猪、牛分割肉及南京各大超市销售的部分肉制品进行了调查,结果表明:猪肉的各部位均无彩虹色斑点现象;牛肉半腱肌中彩虹色斑点的发生率为83%,其他部位从高到低分别为背最长肌(21%),腰大肌(7%),股二头肌(5%)。牛肉制品中帕斯雀牛肉、烤牛肉和酱牛肉彩虹色斑点最明显,猪肉制品中西式火腿片和咸肉最明显。     

Cadmium and lead in animal tissue (muscle,liver and kidney), cow milk and dairy products in Korea

A survey of Cd and Pb in animal tissue, milk and dairy products was conducted. Muscle, liver and kidney of domestically produced cows, pigs, chickens and ducks were collected from eight regions in Korea. Raw cow milk was collected from 9 regions, and imported dairy products (butter, cheese, cream and powdered milk) were collected from 15 countries. Cd and Pb were analysed by inductively coupled plasma mass spectrometry (ICP-MS) after microwave digestion. Concentrations of Cd and Pb did not exceed the Korean legal maximum levels in any of the samples. Correlation coefficients were estimated between concentration of Cd or Pb and animal age and between muscle, liver and kidney. In cows, there were good correlations between age and Cd in kidney (r = 0.748) and between Cd in liver and in kidney (r = 0.878). Continuous monitoring will be an important role to safeguard consumers in the event of a food contamination incident.     

Consumer preferences for beef color and packaging did not affect eating satisfaction

We investigated whether consumer preferences for beef colors (red, purple, and brown) or for beef packaging systems (modified atmosphere, MAP; vacuum skin pack, VSP; or overwrap with polyvinyl chloride, PVC) influenced taste scores of beef steaks and patties. To test beef color effects, boneless beef top loin steaks (choice) and ground beef patties (20% fat) were packaged in different atmospheres to promote development of red, purple, and brown color. To test effects of package type, steaks and patties were pre-treated with carbon monoxide in MAP to promote development of red color, and some meat was repackaged using VSP or PVC overwrap. The differently colored and packaged meats were separately displayed for members of four consumer panels who evaluated appearance and indicated their likelihood to purchase similar meat. Next, the panelists tasted meat samples from what they had been told were the packaging treatments just observed. However, the meat samples actually served were from a single untreated steak or patty. Thus, any difference in taste scores should reflect expectations established during the visual evaluation. The same ballot and sample coding were used for both the visual and taste evaluations. Color and packaging influenced (P<0.001) appearance scores and likelihood to purchase. Appearance scores were rated red>purple >brown and PVC >VSP>MAP. Appearance scores and likelihood to purchase were correlated (r=0.9). However, color or packaging did not affect (P>0.5) taste scores. Thus, consumer preferences for beef color and packaging influenced likelihood to purchase, but did not bias eating satisfaction.     

禽肉的感官鉴别

本文介绍了鲜禽、冻禽、白条禽的感观特征和质量鉴别方法     

宰前短期饮水中添加VC对育肥猪肉品质的影响

试验考察宰前48 h饮水中添加VC对育肥猪血液指标、肉品质的影响.结果表明:宰前饮水短期添加VC对育肥猪胴体品质无影响;与对照组相比,添加VC 500和1 000 mg/L组血浆VC含量提高(P＜0.05),肉的亮度L*24h降低(P＜0.05);添加500 mg/L组肉的红度(α*24h)增加(P＜0.05).添加V...     

日粮中添加牛至精油改善牛肉熟化过程中的肉品质

为研究日粮中添加牛至精油对牛肉熟化过程中食用品质的影响,选择10头体重相近、健康无疾病的荷斯坦奶公牛,随机平均分成实验组(添加牛至精油)和对照组(未添加牛至精油),相同环境下饲喂8个月后屠宰,测定肉品质。结果显示:熟化时间和牛至精油对肉色变化存在互作效应(p<0.05)。熟化0 d实验组亮度(L*)、黄度(b*)显著低于对照组(p<0.05),红度(a*)低于对照组(p>0.05);熟化第7 d,红度有显著高于对照组的趋势(p<0.10);在熟化过程中,剪切力、失水率、蒸煮损失均低于对照组(p>0.05),熟肉率均高于对照组(p>0.05),p H变化较对照组稳定。该结果提示在日粮中添加牛至精油,一方面可以更长时间保持肉的红色度,显著降低亮度、黄度,维持p H稳定,另一方面,可以改善嫩度,降低失水率和蒸煮损失,提高熟肉率,改善牛肉品质。      

Evolution of hydrophobic polypeptides during the ageing of exudative and non-exudative pork meat

Thirty-six carcasses from 6-month-old pigs were classified in different exudative groups based on measurements of pH_2h, pH_24h, the colour parameter L^* and drip loss. A fraction containing polypeptides between 66 and 21 kDa was analysed by reverse phase chromatography at 2-h post-mortem and the evolution of 8 polypeptide fractions followed during ageing and related to meat quality. Three polypeptide (fractions P2, P3 and P4) at 2-h post-mortem showed significant lowest area values in the dark firm and dry class. During ageing, the higher content of P4 in exudative meats at 8-h post-mortem could be due to activation of the cathepsin system. On the other hand, P3 and P4 increased in DFD meats during the first 96-h post-mortem probably due to higher calpain activity. Few differences in polypeptides were related to meat qualities although they are important as precursors of small peptides and free amino acids.     

Biogenic amines in selected foods of animal origin obtained from the Croatian retail market

ABSTRACT

This study aimed to investigate the presence of eight biogenic amines (BAs): tryptamine (TRP), phenylethylamine (PHE), putrescine (PUT), cadaverine (CAD), histamine (HIS), tyramine (TYR), spermidine (SPD) and spermine (SPM) in cheese, fish & fishery products and meat & meat products obtained from the Croatian retail market. A selective and robust method of high-performance liquid chromatography (HPLC) with diode array detection (DAD) was applied for the determination of BAs in a total of 91 samples in accordance with the performance criteria outlined in the European legislation. A high inter- and intra-food group variability of the amounts of BAs was observed. In the analysed samples, the most represented amines were TYR, HIS, CAD and PUT. Based on the highest content of the most toxic BAs (HIS and TYR) and consequential food safety concerns, the studied food groups can be ranked in the following order: cheese (HIS up to 106.4 mg/kg; TYR up to 206.6 mg/kg), fish &fishery products (HIS up to 98.8 mg/kg; TYR up to 47.9 mg/kg), and meat & meat products (HIS up to 20.0 mg/kg; TYR up to 117.5 mg/kg). The total BA content was significantly higher (p < .05) in fermented in comparison with other food. The study aimed to contribute to the knowledge on BA toxicity and food quality, as well as to support the indispensable future studies of consumption data and exposure assessment, to the end of defining allowable BA concentrations in food.     

Species identification of meat products by ELISA

ELISA methods used in this study are proved to detect low contents of animal species (pork, beef, sheep and poultry), even in highly processed foods. They present the advantages of being robust, cheap and easy to perform. Nevertheless, F factors, determining the threshold values of the test, need to be validated for each species.