The effects of dietary α-tocopheryl acetate supplementation and modified atmosphere packaging (MAP) on the quality of lamb patties

Contributions to water retention capacity (% WRC) and texture changes were determined for pork by-products (lung lobes, kidneys), chicken viscera (head, feet and viscera) and mechanically separated chicken (MSC) as affected by pH and various salts in a high-moisture model system. The % WRC for meat by-products and MSC was increased by increased pH (4.5-6.8). Pork lungs and MSC had the highest % WRC (p<0.05) among the meat by-products. Meat by-product % WRC was not signifcantly (p>0.05) affected by salt (2%), phosphate (0.3%) or NaOH (0.075%). Chicken viscera had the lowest (p<0.05) mean texture measurements among the meat by-products and MSC. Strong negative correlations (p<0.05) were obtained for texture with total collagen, soluble collagen and high ionic strength soluble (HIS) proteins. These results should be considered for product quality changes when these by-products are used in formulation of high moisture pet food products.     

Meat By-product Protein Composition and Functional Properties in Model Systems

Composition and functional properties of selected meat by-products were studied. Mechanically deboned chicken meat (MDCM) and meat by-products (pork lung lobes, pork liver, beef lung lobes, beef spleen, beef heart) varied in their proximate composition, amount of the three major protein fractions [low ionic strength soluble (LIS), high ionic strength soluble (HIS), insoluble] and collagen content. Cooked batter model system reheat yield was positively correlated with the quantity of HIS proteins and the percentage myosin and actin in the HIS protein fraction. Stress and strain at failure of the cooked batters were inversely correlated to the amount of LIS proteins and positively correlated with the percentage of myosin and actin in the by-products.     

Myofibrillar protein extracts from spent hen meat to improve whole muscle processed meats

Myofibrillar protein (MP) from spent hen meat was used as an ingredient for chicken breasts and pork hams. Cooking loss (CL) and texture of both products were evaluated. Salt-soluble MP was extracted following centrifugation. A brine with 6% MP or a brine without MP were injected into meat to 20% of the original meat weight. CL was reduced in pork hams treated with 6% MP (P<0.05). Chicken breasts with 6% MP had greater hardness and gumminess than those without MP (P<0.05). Pork hams with 6% MP had greater hardness, gumminess and chewiness than those without MP (P<0.05). It was concluded MP from spent hen meat may be used to improve the functional properties of whole-muscle meat products.     

Effects of cooking on thermal-induced changes of Qingyuan partridge chicken breast

Changes in some properties of cooked 22-weekold Qingyuan Partridge chicken breast were investigated. Cooking losses of meat increased significantly in the range 55–85°C (p<0.05). The heated chicken muscle became lighter and yellower. The shear value of meat decreased markedly to a minimum at 65°C, and increased dramatically upon cooking from 65 to 85°C (p<0.05) with a slight increase from 85 to 100°C (p>0.05). The texture profile analysis parameters of meat changed independently with increasing temperature. Muscle fibers decreased to a minimum (p<0.05) at 65°C with an increase from 65 to 75°C. A significant decrease in solubility of salt-soluble myofibrillar proteins (p<0.05) and an increase in the content of heat-soluble collagen in the range 55–65°C were observed. The results demonstrated that cooking temperature had significant effects on the thermal-induced changes of older chicken and marked changes were happened from 55 to 85°C.     

DSC study on the influence of meat source, salt and fat levels, and processing parameters on batters pressurisation

 Hydrostatic high-pressure/temperature treatments were conducted at low (10 °C) and high temperatures (60, 70, and 80°C) on different types of meat batters. Pressure-induced effects on proteins were intensified by sodium chloride molarity at low and high temperatures. Treatments at 10°C under pressurisation yielded net thermal destabilisation effects on meat proteins pertaining either to muscle or batter systems. Heating at usual cooking temperature of 70°C under pressure yielded net stabilising effects on meat batter proteins. Overheating at 80°C was needed for entire protein denaturation. Pork and chicken meats were very similar in behaviour but chicken batters exhibited relatively higher thermal- and pressure-induced protein denaturation. Both kinds of physical destabilisation/stabilisation of proteins by pressure-induced effects increased with pressure level. Received: 30 December 1999 / Revised version: 14 February 2000     

偏最小二乘回归法分析藏鸡胸肉质地特性

为揭示藏鸡肉独特的质地特性,探寻鸡胸肉质地特性与其化学成分和微观结构的关联性,本研究对5 种不同的鸡肉原料（藏鸡、与藏鸡同日龄或体质量接近的雪山草鸡、淘汰蛋鸡（对照）和白羽肉鸡（对照））进行剪切力、质地剖面分析（texture profile analysis,TPA）和应力松弛特性测定,并将上述质地特性分析结果和鸡肉的基本化学指标（水分质量分数、粗脂肪质量分数、粗蛋白质量分数、胶原蛋白质量分数、pH值）、组织学特征（肌纤维直径和密度）进行关联性分析,利用偏最小二乘回归（partial least squares regression,PLSR）法揭示影响鸡肉质地特征的显著因素。结果发现,利用PLSR能够将多个与肌肉质地特性相关的化学指标量化为鸡肉品质综合评价指标,其中剪切力的预测模型更适合预测鸡肉的质地特性。该模型的R2X为0.621,R2Y为0.739,模型拟合效果较好。Q2cum在0.6以上,说明该模型的可预测性能够被接受。载荷图显示剪切力与pH值、总胶原蛋白质量分数和肌纤维直径呈显著正相关（P＜0.05）,而与粗脂肪质量分数、可溶性胶原蛋白质量分数、胶原蛋白溶解性和肌纤维密度呈显著负相关（P＜0.05）。贡献度评价结果显示,胶原蛋白溶解性、肌纤维密度、可溶性胶原蛋白质量分数和肌纤维直径4 个指标均在模型中贡献显著。本研究可为从质地特性角度揭示藏鸡胸肉特有“咀嚼感”提供数据支持,并为丰富肉的力学特性研究提供一定的理论参考。     

云南武定鸡、盐津乌骨鸡和大围山微型鸡肌肉中脂肪酸的组成分析

以云南省特有的三个优质地方鸡品种:武定鸡、盐津乌骨鸡、大围山微型鸡为研究对象,用溶剂提取法提取3种鸡胸肌及腿肌中总脂质,经甲脂化后,利用气相色谱-质谱(GC-MS)对脂肪酸组成及含量进行分析。结果显示,在云南武定鸡、盐津乌骨鸡和大围山微型鸡胸肌及腿肌中共含有20种脂肪酸,主要包括油酸、亚油酸、棕榈酸、硬脂酸、花生四烯酸。武定鸡与盐津乌骨鸡胸肌中总脂肪含量分别为28.470与25.042 mg/g,显著高于大围山微型鸡的16.769 mg/g(p0.05),大围山微型鸡腿肌中总脂肪含量为51.10 mg/g,显著高于武定鸡40.994 mg/g(p0.05);三种鸡的脂肪酸种类相同,饱和、不饱和脂肪酸占总脂肪酸比例相似,但各脂肪酸含量有所差异,三个鸡种腿肌中脂肪酸含量显著高于胸肌中脂肪酸含量(p0.05)。     

Effect of isoelectric solubilization/precipitation and titanium dioxide on whitening and texture of proteins recovered from dark chicken-meat processing by-products

Processing of chicken generates by-products containing muscle proteins attached to bones and skin that, if recovered, could be a functional ingredient in restructured food products. However, color of restructured products made of proteins recovered from chicken processing by-products is poor. The by-products contain bones, skin, fat, etc. that affect color of restructured products. Therefore, color properties need to be improved. The objectives of this study were to determine effects of isoelectric solubilization/precipitation (ISP) and TiO₂ on instrumental color and texture properties of heat-set gels made of proteins recovered from dark chicken-meat processing by-products as compared to gels made of chicken breast meat. Skin-on bone-in chicken drumsticks were used as a model dark chicken-meat processing by-products. TiO₂ at 0-1 g/100 g and canola oil at 10 g/100 g were added to the ISP-recovered proteins followed by cooking. Due to higher (P < 0.05) yellowness (b∗) and lower (P < 0.05) lightness (L∗), the whiteness of drumstick gels without TiO₂ was lower (P < 0.05) than breast gels. TiO₂ at 1 g/100 g with canola oil resulted in slightly better (P < 0.05) whiteness of drumstick gels than breast gels. TiO₂ did not deteriorate gel texture, which was generally comparable to breast gels. This research indicates that ISP allows recovery of proteins from skin-on bone-in dark chicken-meat processing by-products without removal of bones, skin, and fat prior to processing. Addition of TiO₂ to proteins recovered from these by-products allows development of heat-set gels with color and texture comparable to chicken breast gels. Although this study shows the potential for a novel, marketable food product, sensory tests are recommended.     

Minced Meat Crabcake from Blue Crab Processing Byproducts—Development and Sensory Evaluation

Quantitative and qualitative characteristics of minced meat, mechanically separated from blue crab processing by-product, were determined. Sensory evaluation was performed on crabcakes with various combinations of claw mince/meat (CMM), surimi, and functional soy protein concentrate (SPC). Separation produced 50–58% food-grade mince from picking table by-products and 49% from undersized claws. Claw mince had lower microbial concentrations than the composite picking table by-products. Crabby and beany flavors were influenced (p<0.05) by the CMM ratio but not by SPC. No significant differences were observed for textural characteristics using various levels of CMM. Sensory firmness and cohesiveness scores marginally correlated (p<0.1) with Instron compressive force measurements. Food-grade undersized crab claw mince can be used in value-added products.     

Differentiation in improvements of gel strength in chicken and beef sausages induced by transglutaminase

This research investigated the improvement in the texture of chicken and beef sausages induced by using microbial transglutaminase (MTG). The ε-(γ-glutamyl)lysine (G-L) content and the extractability of myofibrillar proteins from these sausages were also investigated. Treatment with MTG significantly affected the breaking strength score in both meat types, especially for beef cooked at 80°C (p<0.001). The protein concentration of both meat types treated with MTG and extracted in water-soluble protein solution (WSP) was slightly decreased; compared with a significant decrease (p<0.003) in samples extracted in Guba-Straub-ATP solution (GS-ATP). The variation in protein extractability of both meat types could lead to some considerations of the mechanisms and the high affinity reaction between MTG and myosin heavy chain (MHC). SDS-PAGE analysis revealed significant changes in the density of the bands after adding MTG, especially for the beef samples. The G-L content in the presence of MTG was double that in control samples of both meat types. The amount of crosslinking in chicken and beef meat was different and found to be reasonable. Collectively, this suggests that the binding ability of myofibrillar proteins with MTG is strong and dominated by MHC. There was a unique reaction among MHC proteins with MTG molecules considered as a very advantageous reaction. This leads us to suggest that the functional properties of MTG make it a beneficial protein-binding agent, positively helping the functionality of proteins to improve the texture and gelation of meat products that are treated mechanically, such as sausages. Some variation in gel improvement level between chicken and beef sausages was observed; this resulted from the variation in meat proteins in response to MTG, as well as to the original glutamyl and lysine contents.     

Collagen Contents of Chicken Gizzard and Breast Meat Tissues as Affected by Cooking Methods

The changes in collagen contents of chicken gizzard and breast meat during boiling water and pressure cooking were investigated. The loss of collagen in both tissues increased as the cooking time or temperature increased. The percent of collagen in acid- and salt-soluble forms in gizzard was lower than that of the breast meat. The acid- and salt-soluble collagen from water cooked gizzard were lower than those of the pressure cooked gizzard. Cooking gizzard in boiling water containing 0.5% acetic acid or papain significantly (p<0.05) reduced the collagen content of the tissue.     

Determination of total arsenic levels by hydride generation atomic absorption spectrometry in foods from south-east Spain: estimation of daily dietary intake.

The total concentration of arsenic in different foods from south-east Spain was determined by hydride generation atomic absorption spectrometry. Mineralization was carried out with an HNO(3)-HClO(4) mixture in a thermostated sand bath. Arsenic determination was performed by the standard addition method. Analyses of NIST and CBR-CEC reference materials demonstrated the reliability and accuracy of the technique. The highest arsenic levels were found in seafood, cereals, meat and meat by-products. In meat and meat by-products, the total arsenic measured in meat was significantly higher than that in sausages (p<0.05). In cereals, arsenic concentrations in corn and white rice samples were significantly higher (p<0.01) than those measured in wheat by-products. Mean arsenic concentrations in cheese were statistically lower than those in other dairy products (p<0.01). New data have been provided on the total arsenic content of a variety of foods in Spain, which is important for making exposure estimates. The estimated daily intake of total arsenic in the Spanish diet was 221 microg As day(-1).     

金鲳鱼不同组织脂肪酸组成比较

为提高金鲳鱼加工中副产物的利用率,本实验采用氯仿-甲醇法提取金鲳鱼5个组织部位中的脂质,采用GC-FID法测定各组织脂肪酸组成。脂质含量由高到低依次为:内脏(27.12±7.96) g/100 g>鱼身骨(16.04±3.35) g/100 g≈鱼头(15.88±3.09) g/100 g>鱼皮(11.93±5.72) g/100 g>鱼身肉(5.09±2.13) g/100 g。5个组织脂肪酸组成基本相同,富含油酸(24.31%~25.84%)、棕榈酸(23.16%~25.00%)和亚油酸(19.04%~19.76%)。饱和脂肪酸(SFA)在内脏(35.32%±2.17%)中含量最高,显著高于其它组织(p<0.05);单不饱和脂肪酸(MUFA)在鱼身骨(34.27%±1.28%)、鱼头(34.56%±1.32%)及鱼身肉(34.34%±1.57%)中含量显著高于内脏(32.68%±1.64%)和鱼皮(33.22%±1.23%)(p<0.05);多不饱和脂肪酸(PUFA)在5个组织间含量无显著差异;n-3PUFA和EPA+DHA在鱼皮(10.34%±1.76%和6.04%±1.53%)中含量最高,显著高于其它组织(p<0.05)。内脏中SFA(35.32%±2.17%) > MUFA(32.68%±1.64%) > PUFA(31.09%±3.18%);鱼身骨、鱼头及鱼身肉中MUFA > SFA ≈ PUFA;鱼皮中SFA(33.70%±2.22%) ≥ MUFA(33.22%±1.23%) ≥ PUFA(32.07%±3.23%)。因此,金鲳鱼组织脂质营养丰富,颇具开发利用价值。     

The chemical and sensory qualities of smoked blood sausage made with the edible by-products of goat slaughter

The aim was to evaluate smoked blood sausage prepared using goat blood (50%), viscera (10%) and meat fragments (20%). Microbiological, chemical and sensory evaluations were conducted. The quality analyses showed that smoked goat blood sausage is rich in high biological value proteins, amino acids, essential fatty acids, and iron (26.65 mg/100 g). The smoked goat blood sausage was rated to have a sensory acceptance of greater than 80%. The use of edible by-products from the slaughter of goats in the formulation of smoked blood sausage is viable because it uses low-cost raw materials; furthermore, the utilisation of these by-products can generate income for producers, allowing them to offer a meat product of high nutritional and sensory quality.     

Extraction of proteins from slaughterhouse by-products: Influence of operating conditions on functional properties

This study investigated the extraction and functional properties of proteins from slaughterhouse by-products: pork lungs, beef lungs and mechanically deboned chicken meat (MDCM). The extraction yield was investigated as a function of pH, temperature and time. Membrane technology was used for purification of proteins from pork and beef lungs, while for MDCM a method based on PI was applied. In the three cases, yields of protein recovery were between 48 and 55% (w/w). The functional properties of the protein concentrates were compared to those of some commercial ingredients. Proteins from pork lungs and MDCM exhibited better gelling properties than egg white and beef plasma, while beef and pork lungs displayed very good emulsifying properties, similar to Na-caseinates. As the methods developed are easy to scale-up, the use of by-product proteins at industrial scale appears to be an interesting opportunity to obtain added value slaughterhouse by-products.     

Comparative studies on chemical composition and thermal properties of black tiger shrimp (Penaeus monodon) and white shrimp (Penaeus vannamei) meats

Chemical composition and thermal properties of meat from two species of shrimps, black tiger shrimp (Penaeus monodon) and white shrimp (Penaeus vannamei), were comparatively studied. White shrimp meat had higher protein and ash contents than had black tiger shrimp meat (p < 0.05). Fractionation of nitrogenous constituents revealed that myofibrillar protein was the major component in the muscles; myosin heavy chain (MHC) and actin were the predominant proteins. White shrimp meat comprised higher stromal protein with greater pepsin-soluble collagen and insoluble collagen contents than did black tiger shrimp meat. Muscle proteins from black tiger shrimp, especially MHC, had higher thermal stability than those from white shrimp as indicated by the higher transition temperature (T_max) as well as the lower inactivation rate constant (K_D). Phospholipid was the predominant lipid (72–74%) in both shrimps, followed by triglyceride. Polyunsaturated fatty acids were found as the major fatty acids with the range of 42.2–44.4%. DHA (22:6)/EPA (20:5) ratio in black tiger shrimp (2.15) was higher than that in white shrimp (1.05). Mg was the dominant mineral in both shrimps. Ca and Fe were also found at high concentrations. Arginine was the most abundant amino acid, while leucine, isoleucine and proline were predominant in both shrimps. Glutamic acid and glycine contents were greater in black tiger shrimp meat; however, white shrimp meat had higher hydroxyproline content. Different compositions might govern the different characteristics as well as thermal properties of both species.     

Production of Restructured Meat using Microbial Transglutaminase without Salt or Cooking

To produce restructured meat, microbial transglutaminase (MTGase) was evaluated for its ability to introduce covalent crosslinks between protein molecules. Pork muscle cubes were mixed with MTGase and held at 5°C for 2 hr for the enzyme reaction. Restructured products were analyzed for binding strength without cooking. MTGase treatment resulted in effective binding of meat pieces provided there was addition of salt (NaCl). To ensure proper binding without NaCl, some food proteins with MTGase were also investigated. Meat cubes in combination with MTGase and sodium caseinate showed acceptable bind, and sodium caseinate appeared to be a superior substrate for the crosslinking to meat proteins than soy protein, whey protein, or gelatin. These results suggest a useful method for producing restructured meat which can be distributed in the raw, chilled state.     

Effects of goat milk or milk replacer diet on meat quality and fat composition of suckling goat kids

The effects of a diet with goat milk "GM" or milk replacer "MR" on the meat quality and fat composition of suckling Murciano-Granadina kids were studied. MR consisted of powdered skimmed milk, coconut oil and fat, and cereal products and by-products. Raw meat quality (moisture, protein, lipids, ash, collagen, cholesterol, haem pigments, CIELab colour, pH and water retention capacity), fatty acid "FA" composition and eating quality of cooked meat (odour, flavour and texture) were determined. Diet had only a slight effect on raw meat quality but had a pronounced effect on fatty acid composition and eating quality of cooked meat. MR diet increased the water/protein proportion in the muscle. The saturated/unsaturated FA ratio in GM and MR fat was 0.94 and 2.27, respectively. The major FA in GM and MR fat were C16:0 and C18:1, respectively. Short-chain C4-C12 hardly accumulated in the adipose tissue of suckling kid, increasing the relative percentages of C14-C20. This effect was more pronounced in MR fat, due to the fact that MR contained more short-chain fatty acids than GM. MR diet gave cooked meat a more intense characteristic goat meat odour and flavour, more tenderness and more juiciness than the natural suckling diet. This fact could be related to differences in meat and fat composition.     

Protein and mineral characterisation of rendered meat and bone meal

We report the characterisation of meat and bone meal (MBM) standards (Set B-EFPRA) derived from cattle, sheep, pig and chicken, each rendered at four different temperatures (133, 137, 141 and 145 °C). The standards, prepared for an EU programme STRATFEED (to develop new methodologies for the detection and quantification of illegal addition of mammalian tissues in feeding stuffs), have been widely circulated and used to assess a range of methods for identification of the species composition of MBM. The overall state of mineral alteration and protein preservation as a function of temperature was monitored using small angle X-ray diffraction (SAXS), amino acid composition and racemization analyses. Progressive increases in protein damage and mineral alteration in chicken and cattle standards was observed. In the case of sheep and pig, there was greater damage to the proteins and alteration of the minerals at the lowest treatment temperature (133 °C), suggesting that the thermal treatments must have been compromised in some way. This problem has probably impacted upon the numerous studies which tested methods against these heat treatments. We use protein mass spectrometric methods to explore if thermostable proteins could be used to identify rendered MBM. In more thermally altered samples, so-called ‘thermostable’ proteins such as osteocalcin which has been proposed as a ideal target to speciate MBM were no longer detectable, but the structural protein type I collagen could be used to differentiate all four species, even in the most thermally altered samples.     

鳄鱼肉主要营养成分及与其他畜禽肉的比较

为了充分了解鳄鱼肉的营养特性,更好地利用鳄鱼资源,本实验分析鳄鱼肉的主要组分、脂肪酸及氨基酸的构成,并与羊肉、猪肉、牛肉和鸡肉进行比较.结果表明:与其他畜禽肉相比,鳄鱼肉是一种高蛋白、低脂肪的优质肉品,多不饱和脂肪酸含量丰富,尤其是花生四烯酸、二十碳五烯酸(EPA)和二十二碳六烯酸(DHA).鳄鱼肉富含必需氨基酸,尤其是赖氨酸.且根据必需氨基酸指数,鳄鱼肉的营养价值高于其他畜禽肉.综合看来,鳄鱼肉是较理想的动物蛋白及脂肪来源.