Selected Macro and Micro Minerals in Ground Beef and Longlssimus Muscle

Up to date values for nutrient composition of foods are required so nutritionally optimum diets can be determined. Selected minerals in longissimus muscle and ground beef from 20 beef carcasses were determined by inductively coupled plasma emission spectroscopy. Ground beef contained greater (P<0.003) amounts of Na, Ca, Fe, Mg and Zn than longissimus muscle. Longissimus muscle contained more (P<0.0073) K and P. The amount of Cu was the same (P<0.699). There were no detectable amounts of Mn observed Mean percentages on an “as is basis” for moisture (71.7 vs 65), protein (23.2 vs 18.8) fat (4.5 vs 16) and ash (0.6 vs 1.0) for longissimus muscle and ground beef, respectively, were different.     

Content of Zinc in Selected Muscles from Beef, Pork, and Lamb

Zinc concentration was measured in four muscles from beef, pork, and lamb: longissimus dorsi (LD), biceps femoris (BF), gluteus medius (GM), and triceps brachi (TB). Within a species, BF, GM, and LD had similar zinc concentrations but TB was significantly (P<0.01) higher in zinc. The means for the four muscles ranged from 39.8–53.5, 13.9–28.0, and 28.2–36.9 μg Zn/g wet weight for beef, pork, and lamb, respectively. The zinc concentration of muscle may relate to protein synthesis and the predominant type of energy metabolism occurring in the muscle. The mean zinc concentration of the four muscles between species was significantly (P< 0.01) different.     

Thermal Gelation Properties of Protein Fractions from Pork and Chicken Breast Muscles

Thermal gelation properties of myosin, actin, myofibrils (MF), sarcoplasmic protein (SP) and connective tissue (CTS) from pork semimem-branosus and chicken breast (CB) were evaluated. Gels were prepared at pH 6.0, 2% NaCl and cooked to 70°C at 0.7°C/min. Pork myosin had a higher gel strength and a lower cooking loss than CB myosin at 7% protein. Actin from both species did not form a measurable gel. MF gels from pork and CB had the lowest cooking loss while CTS and SP had the highest cooking loss. Difference in gel strength between muscle and MF+SP+CTS at 7% protein was not consistent with that at 10% protein.     

Minerals in Pork Meat and Edible Offal

Pork meat contains important minerals, including iron and zinc, all of which are essential for good health throughout life. Edible offal is also a form of meat and in general possesses a higher content of minerals, than muscular tissue. The mineral levels in pork meat, and edible offal are variable. Major sources of variation in animal products are the proportion of lean to fat tissue, and the proportion of edible to inedible materials. The aim of this paper is to provide an overview of the existing scientific literature on the mineral levels in pork meat and edible offal.     

不同磷酸盐对猪肌肉嫩度及保水性的影响

以猪背最长肌为原料,选择不同浓度多聚磷酸盐、六偏磷酸盐和焦磷酸盐对样品进行盐水注射和滚揉处理,采用正交试验设计,测定肌肉嫩度、滴水损失率、离心损失率、蒸煮损失率,研究磷酸盐对肌肉嫩度及保水特性的影响。结果表明：不同磷酸盐对肌肉嫩度及保水性的不同指标影响不同,其中多聚磷酸钠对肌肉嫩度有显著影响(P ＜ 0.05)。当焦磷酸钠:多聚磷酸钠:六偏磷酸钠为0.3%:0.3%:0.2% 时,其嫩化效果最明显。多聚磷酸盐对滴水损失率、蒸煮损失率有影响显著(P ＜ 0.05)。依据蒸煮损失率确定的磷酸盐最佳组合为0.2% 焦磷酸钠-0.3%多聚磷酸钠-0.2% 六偏磷酸钠。     

Nutrient Content and Edible Yield of Selected Cuts of Cooked Pork

Analysis of lean-type pork cooked by standard methods showed that cooking to a final internal temperature of 77°C for fresh cuts, and 71°C for cured meats resulted in increased amounts of several essential nutrients. Edible yield was similar to that reported from earlier studies, while amounts of internal fat were somewhat lower. Levels of thiamin, riboflavin and niacin and of several minerals were found to be slightly higher than Handbook 8 values. Cobalamin and zinc from 100g of edible lean would provide approximately 10% and 20–35% of the respective recommended daily allowances. Iron contents were lower than previously reported for pork.     

单道扫描ICP-AES法同时测定食品中十一种常量及微量元素

本文研究了食品中十一种常量及微量元素(K、Na、Ca、Mg、P、Cu、Fe、Zn、Mn、Ni和St)单道扫描ICP-AES测定的方法。试验了仪器工作参数的选择,探讨了分析线的选择与背景校正,用表面活性剂解决雾化器喷雾堵塞问题,效果良好,并可维持一定的灵敏度,方法的RSD在3.1～10.1％之间,回收率在91～105％,基体元素对微量元素的测定基本无影响,对标准物质测定结果令人满意,方法适用于食品中上述元素的测定。     

Effect of Animal Age on the Tenderness of Selected Beef Muscles

The tenderness of 12 beef muscles from animals of 8 different age groups (ranging from 1 to about 60 months old) which were treated to minimize pre-rigor myofibrillar shortening, have been assessed using objective and subjective methods. The mean tenderness of these 12 muscles significantly (p<0.001) decreased with age. The rate of increase in the toughness of individual muscles with animal age was related to their connective tissue strength. Psoas major muscles were almost unaffected by increasing animal age whereas high connective tissue strength muscles, such as the Biceps femoris, trebled in toughness. A comparison of the different muscles revealed that one of the least representative was the often used M. longissimus dorsi.     

Dietary Iron in Swine Rations Affects Nonheme Iron and TBARS in Pork Skeletal Muscles

Fifteen crossbred pigs (mean wt = 25 kg) were allocated to three groups and fed to market weight (mean wt = 103 kg) on corn-soy based diets containing either 62,131, or 209 ppm iron. After slaughter, the longissimus dorsi (LD) and rectus femoris (RF) muscles were dissected, cooked, and stored in oxygen-permeable bags for 12 days at 4°C. Cooking increased thiobarbituric acid reactive substances (TBARS) but did not affect nonheme iron (NHI) or α-tocopherol. NHI and TBARS increased continuously during storage while α-tocopherol decreased. NHI and TBARS were higher in cooked pork from pigs fed high-iron diets. Liver iron correlated with muscle iron (p<0.05).     

Effect of Postmortem Storage on Titin and Nebulin in Pork and Poultry Light and Dark Muscles

Purified myofibrils were prepared from samples of chicken breast and thigh muscles and from light and dark portions of pork semitendinosus muscle at death and after storage at 4° and 22°C for 1, 3, and 7 days postmortem. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) was used to examine the effect of postmortem storage of muscle on titin and nebulin. Results indicated that titin and nebulin were more rapidly degraded in light than in dark chicken muscle. In contrast, titin and nebulin were more rapidly degraded in dark than in light pork muscle.     

Yield and Comparison of Nutritive and Energy Values: Selected Variety Pork Products

Eight raw and cooked pork products were compared for yield and physiologic energy values, nutrient composition and protein quality. Cracklings were not cooked. Cooking resulted in some significant changes (wet basis) in parameter values. Knuckles and ham hocks had similar parameter values. All products, except skin, had a cooking loss. Skin had a 15.3 g/kg gain, apparently due to an exceptional moisture increase. The fat composition showed a very low ratio of polyunsaturated to total saturated fats. There were no differences between the calculated PERs of each raw and cooked product. These data indicated that the chemical score and the PER values of these products were generally directly proportional to the total quantity of essential amino acids present.     

Mineral Composition of Selected Bovine, Porcine and Avian Muscles, and Meat Products

THE MINERAL CONTENT of young and old avian muscles, in mature bovine and porcine tissues destined for processing, and in selected meat products and additives was determined. Inter- and intra-species variations in mineral composition were found among all the muscle tissues investigated. Muscle-to-muscle variation was found to be highly significant for all but one of the minerals analyzed in the avian (K) and bovine (P) muscle tissues and all but three (Fe, Ca, P) in the porcine tissues. The mineral content of three major meat products and four meat additives are reported. The least variability in tissue mineral content was found when the data was expressed on a dry weight, fat free basis.     

微滴式数字PCR对肉制品中羊肉和猪肉定量分析

为了实现肉制品中羊肉和猪肉的量化研究,本文应用微滴式数字PCR对肉制品进行定量检测。通过在看家基因上设计单拷贝特异性引物,能更好的鉴别是人为因素的掺假还是在加工过程中无意的带入。根据dd PCR的结果显示,在一定范围肉质量和DNA的浓度,DNA浓度和DNA拷贝数(C)成现一定的线性关系。通过人为掺假及市售样品检测以验证此方法。以DNA浓度作为中间换算值,得到肉质量和DNA拷贝数之间的换算关系M_羊=0.12C-10.6 M_猪=0.07C+4。通过对已知掺假比例的肉样及市售样品进行检测,能够较好的得到掺假肉的质量。目前市场上存在一定的掺假现象且该检测方法具有一定市场应用前景,本文建立的微滴式数字PCR在羊肉和猪肉及其制品中的掺假检测具有较强的应用潜力,对目前混乱的肉制品掺假的市场监管提供了科学的依据。     

不同蛋白源日粮对猪肌肉中呈鲜物质含量及肉香味的影响

本实验通过高效液相色谱法分别分析了猪背最长肌中肌苷酸和游离氨基酸的含量,同时,采用口感品尝评定法评价了饲以不同蛋白源日粮试猪背最长肌的香味,研究了日粮中不同蛋白源对猪肌肉中呈鲜物质含量及肉香味的影响。结果显示,不同蛋白源日粮可以显著或极显著地影响肌肉中肌苷酸的含量(p<0.05或p<0.01);此外,不同蛋白源日粮还可显著地影响肌肉香味(p<0.05);但试验却未发现不同蛋白源对肌肉中游离鲜味氨基酸有显著的影响(p>0.05)。     

OCC回用过程中胶黏物的定量分析及浮选控制

以废纸为原料生产挂面纸板会给造纸厂带来许多问题.如果不进行适当控制,就会引起产品质量下降,并影响纸机正常运行.为解决废纸造纸带来的诸多问题,科研工作者进行了广泛的研究并开发出了许多新技术方法,如纤维分级、磨浆前用酶处理回收纤维、表面施胶和Condebelt干燥等.近来,许多造纸生产者已经意识到了废纸回用中控制胶黏物的重要性.因此,有必要确立胶黏物定量分析的标准方法,以此来评价胶黏物对产品质量和纸机运行状况的影响,并测定造纸过程中不同部位的胶黏物含量.     

Proximate Analyses, Selected Vitamins and Minerals and Cholesterol Content of Mechanically deboned and Hand-deboned Broiler Parts

Samples of commercial mechanically deboned broiler product derived from necks, with and without skin, backs and rib cages, separately and combined into blended mixture were analyzed. Moisture content ranged from 62.7–73.4%, fat from 13.2–25.2%, protein from 10.3–11.9% and ash from 0.74–0.94%. Vitamin analyses (mg/100g wet weight) included: thiamin 0.051–0.068, riboflavin 0.128–0.211, niacin 2.50–3.39, vitamin B₆ 0.094–0.149, and pantothenic acid 0.581–0.700. Cholesterol content was 94.2–129.1 mg/100g wet weight. Mineral content (mg/100g) was K 123–151, Na 48–62, Ca 53–91, Mg 13–15, Zn 1.13–1.78, Fe 1.45–1.86, Mn 0.019–0.026, and Cu 0.029–0.034. One batch each of necks with and without skin, and backs was hand deboned and analyzed. Calcium and cholesterol contents were 350 and 14% higher, respectively, in mechanically deboned products as compared to the hand-deboned counterparts. There were differences in vitamin levels due to source of material, but not due to method of deboning.     

Thermal Gelation of Pork, Beef, Fish, Chicken and Turkey Muscles as Affected by Heating Rate and pH

Effects of heating rate (3°C or 0.7°C/min) and pH (5.5, 6.0, 6.5, or 7.0) on thermal gelation properties of different muscle systems were evaluated (10% protein, 2% NaCl) using pork, beef, fish, and chicken and turkey (breast and thigh) muscles. Results indicated that, at pH 6.5 and 7.0, force required to rupture the gel (Pf), force required to move plunger through the gel (Fp), and viscosity index (Ni), using a slow heating rate, were higher than with rapid heating. All muscles (except breast muscles with the slow heating rate) yielded higher (P<0.05) gel strength (Fp, Pf) at pH 6.0 than at the other pHs.     

市场鲜猪肉掺假状况的调查监测

肉品安全问题是食品安全的一个重要组成部分。通过调查我们发现,鲜猪肉掺假的手段主要有注水,掺加亚硝酸盐以及合成色素等,这不仅给消费者带来经济损失,更加影响消费者身体健康。针对以上原因,我们对超市、集贸市场、肉品专卖店等地点的肉样进行随机抽样,进行掺假检测。结果表明,市场中猪肉的安全质量还存在很大问题。