Nutrient Composition of Fresh Retail Pork

The nutrient composition of fresh pork was studied in samples from 71 carcasses. On separable lean, nutrient composition was determined for 7 raw retail cuts from one side of each of 11 carcasses, and nutrient retention was determined on the 7 matching cuts from the other side that had been cooked by common household methods. Loins from 60 additional carcasses were analyzed to determine whether USDA grades 1, 2, and 3 and region of production affected nutrient composition. The data indicated that variation in nutrient composition of pork is more dependent on the retail cut within the carcass than either the grade or the region of production of the carcass. Cooking method significantly affected retention of most of the nutrients analyzed.     

Metmyoglobin Reducing Capacity of Fresh Normal, PSE, and DFD Pork During Retail Display

Fresh pale, soft, exudative (PSE), dark, firm, dry (DFD), and normal pork were stored under light or dark conditions at 4°C for 7 days. Sample pH, metmyoglobin reductase activity, oxygen consumption rate, and relative surface metmyoglobin and oxymyoglobin contents were determined. DFD pork had the highest metmyoglobin reductase activity and oxygen consumption rate. Enzyme activity of PSE was lower than that of normal pork, but no difference existed in oxygen consumption rate between PSE and normal samples. Metmyoglobin reductase activity dropped slowly during meat storage; oxygen consumption rate sharply decreased during the first day of storage. Both metmyoglobin reductase activity and oxygen consumption rate declined more rapidly in the light. Results can help develop guidelines for display and packaging of pork.     

Extension of the Retail Display Life of Fresh Beef Packaged in Modified Atmosphere by Varying Lighting Conditions

ABSTRACT: The effect of lighting conditions (darkness and either a standard supermarket fluorescent, a low-UV, color-balanced lamp, and the supermarket fluorescent with a UV filter) on the retail display life of fresh beef steaks packaged in a modified atmosphere was studied. Lighting without UV radiation led to a significant delay of meat spoilage, as assessed by surface color (a* and MetMb percentage), lipid oxidation (TBARS value), bacterial counts and sensory evaluation (discoloration and odor). Shelf life of fresh meat was extended from 12 to 22 to 28 d, similar to that of display in the darkness, by using either the low UV lamp or the fluorescent with a UV filter.     

Discoloration of Fresh Pork as Related to Muscle and Display Conditions

Pale, soft, exudative (PSE), normal, and dark, firm, dry (DFD) pork was held 7 days at 4°C under light or dark then color was evaluated instrumentally and visually. Change in reflectance (R630-R580) was used to estimate color changes due to oxymyoglobin. PSE pork was lighter (high L*) than normal and DFD pork, but did not change over time. An increase in a* and R630-R580 occurred the first day for normal and DFD, but not for PSE samples. A subsequent increase in hue angle and decrease in R630-R580 (loss of redness) occurred in PSE and normal, but not in DFD samples. Changes in hue angle and R630-R580 were more rapid in PSE than in normal samples. Light exposure accelerated all changes except L*. Visual redness inversely correlated with L* value.     

Potassium Lactate Effects on Low-Fat Fresh Pork Sausage Chubs During Simulated Retail Distribution

Typical pork sausage (25% fat) and low-fat (8% fat) sausage with or without 20% added water and 0.4% carrageenan were compared to identical treatments containing 3.0% potassium lactate. Microbial populations of low-fat treatments did not differ (P>0.05). However, typical sausages with lactate had lower psychrotrophic counts than typical sausage. Lactate delayed (P<0.05) pH decline in typical sausages but had no effect on low-fat sausages (P>0.05). Addition of water and carrageenan to commercially manufactured and distributed low-fat sausage had no deleterious effects on microbial, lipid or color stability.     

迷迭香对生鲜猪肉颜色变化与抗氧化稳定性的影响

选用鼠尾草酸质量分数分别为5%和20%的迷迭香(CAP05、CAP20),分别以一定质量浓度梯度喷射到生鲜猪肉表面,并将猪肉置于超市标准荧光灯下冷藏8d。检测迷迭香对猪肉贮藏期间CIE a*值、色相、氧合肌红蛋白、正铁肌红蛋白、TBARS值、蛋白质羰基和感官评价的影响。实验发现,5%鼠尾草酸的抗氧化效果总体优于20%鼠尾草酸的作用效果,其中r500、r1000和R500组较大程度上延缓了肉品的变色及脂肪和蛋白质的氧化,且r500组肉品在第8天变色最轻、异味最少。统计分析发现猪肉的氧合肌红蛋白、正铁肌红蛋白、TBARS值和蛋白质羰基与颜色CIE a*值之间具有极显著的相关性(P0.01)。     

Effects of Simulated Retail Display and Overnight Storage Treatments on Quality Maintenance in Fresh Broccoli

The quality of fresh broccoli during simulated retail display was evaluated using contact (ice) and air cooling separately and in combination. Chlorophyll and ascorbic acid were best maintained with air cooling, while weight was best maintained with ice cooling alone. In air-cooled display units, ice placed both on top of and beneath broccoli heads resulted in more rapid loss of chlorophyll and ascorbic acid than did bottom-icing alone. Bottom-iced broccoli in air-cooled units kept best overnight if left in place and covered with wet burlap. Removal to a 4°C walk-in cooler each night resulted in good color retention and marketability but weight loss after 4 days was significantly higher.     

迷迭香与高氧气调对生鲜猪肉的护色及抗氧化效果

研究迷迭香、高氧气调包装及两者结合使用对生鲜猪肉颜色稳定性和肉品抗氧化的影响。生鲜猪肉经不同质量浓度迷迭香处理,进行高氧气调包装或聚乙烯薄膜包裹,于4℃有光照环境中贮藏10d,分析猪肉在贮藏期间颜色、正铁肌红蛋白、TBARS值、蛋白质羰基、血红素铁、质构及感官的变化情况。实验发现高氧气调增加了猪肉红色的持留能力,但同时加剧了脂肪氧化,对肉品嫩度也造成不利影响。迷迭香对猪肉的护色和抗氧化效果受到高氧气调的影响。迷迭香与高氧气调结合有效延缓了猪肉脂肪氧化,但是对蛋白质羰基的抑制效果并不明显,而低质量浓度迷迭香对非气调包装中猪肉蛋白质羰基的生成起到了良好的抑制作用。     

Effects of Packaging Method, Display Light and Storage Time On The Microbial Growth and Rancidity of Fresh Pork

Effects of display light, packaging methods and storage time on total aerobic, lipolytic and proteolytic counts and oxidative rancidity of fresh pork stored at 2 ± 1° C were studied at the initial, 7th, 14th and 21st day of storage. Display light significantly increased the total aerobic psychrotroph count. Effects on lipolytic and proteolytic psychiotroph counts were not significant. No anaerobic psychrotrophs were encountered. Total and proteolytic counts of PVC film overwrapped chops and proteolytic and lipolytic psychrotroph counts of chops vacuum packaged accelerated linearly with time. Increases in lipolytic psychrotroph count of PVC packaged and total aerobic psychrotroph count of vacuum packaged chops were quadratic. TBA number and rancid odor scores were not significantly affected by treatments.     

服装零售店的陈列与设计

主要介绍了现代意义上的服装零售店的陈列和设计方法.     

含迷迭香的蛋白基薄膜对高氧气调包装生鲜猪肉的护色及抗氧化作用

以不同质量浓度迷迭香与大豆分离蛋白复合制备活性蛋白膜,并将该蛋白膜用于高氧气调下生鲜猪肉的护色保鲜。分析猪肉贮藏期间CIE a*值、正铁肌红蛋白、硫代巴比妥酸反应（thiobarbituric acid reactive substances,TBARS）值、蛋白质羰基及肉品硬度的变化情况。结果表明：肉样表面喷洒0.05 g/100 mL迷迭香提取物有效抑制了高氧气调包装肉品的脂类氧化和贮藏后期的颜色劣变。而蛋白膜加入不同质量浓度迷迭香对高氧气调包装的猪肉表现出不同的抗氧化活性。纯蛋白膜和0.025 g/100 mL迷迭香包装组对猪肉没有表现出护色作用,但对猪肉贮藏期间脂类和蛋白质的氧化起到了一定的抑制作用;0.1、0.2 g/100 mL迷迭香包装组有效延缓了猪肉a*值的下降和正铁肌红蛋白、TBARS值的生成,且其对猪肉的护色效果好于迷迭香直接喷洒处理,但无法抑制蛋白质羰基的形成。而0.05 g/100 mL迷迭香包装组在整个贮藏期间对猪肉颜色、脂类、蛋白质等的抗氧化效果均好于迷迭香直接喷洒处理,且基本维持了肉品贮藏期间的硬度,这表明蛋白膜对迷迭香的包埋显著提高了迷迭香对高氧气调下猪肉的抗氧化活性。     

Acceptability and Shelf-life of Marinated Fresh and Precooked Pork

Fresh (FL) and precooked (PL) longissimus chops and fresh semi-membranosus/adductor (SM) roasts were evaluated to determine acceptability of marinated pork. Citric acid and sodium acid pyrophosphate lowered pH (CAP), sodium acid pyrophosphate attained intermediate pH (SAP), and sodium tripolyphosphate increased pH (TPP). In FL and SM cuts, TPP improved sensory characteristics, water-holding capacity (WHC) and processing yields. CAP reduced microbial growth in FL chops and improved tenderness in SM roasts. In PL cuts, TPP improved juiciness and reheating yields. Marinating at low pH reduced microbial growth; marinating at high pH improved sensory properties, WHC, fresh pork processing yields and precooked pork juiciness and reheating yields.     

新鲜猪肉气调保鲜包装技术

本文介绍新鲜猪肉气调保鲜包装混合气体的组成,鲜肉色泽的保持和防腐效果。通过新鲜猪肉的气调包装和真空包装保鲜效果试验得出:在0～6℃温度贮藏14天后,两种包装的防腐效果和保持色泽相比较,气调包装新鲜猪肉的细菌总数低于真空包装,血色素指标是真空包装的三倍。两种包装新鲜猪肉的pH、TVBN值都符合卫生指标要求。     

鲜猪肉中磺胺类抗生素残留的检测与分析

采用高效液相色谱法（HPLC）对64份来自某城市市区及郊区鲜肉市场的生鲜猪肉样品中10种磺胺类抗生素的残留进行检测。结果显示,磺胺类抗生素的检出率和超标率分别为20.31%和10.94%,其中郊区的检出率和超标率均高于城区。10种磺胺类药物中检出率最高的是磺胺嘧啶（SD）,为7.81%,其次是磺胺甲二唑（SMT）和磺胺吡啶（SP）,分别为6.25%和4.69%。此结果表明,部分鲜猪肉中磺胺类抗生素的残留量较高,有诱发产生耐药菌的潜在威胁,相关部门应加强指导养殖业抗生素的合理使用。     

Sampling of Fresh Pork for Nutrient Analysis

Paired loins from 18 barrow and gilt carcasses were randomly selected to evaluate the effect of marketing on the nutrient composition of fresh pork loins. The paired loin from one side was shipped through a predetermined marketing system, while the control loin was transported immediately back to Beltsville, MD. Rib chops from each loin were analyzed for key nutrients. The overall results from this study indicate that pork loins subjected to extreme marketing conditions have weights, appearance and quality traits and nutritional composition similar to loins shipped from a slaughter plant directly to the research facility. Thus, pork samples handled by a controlled research technique and sampled at the point of slaughter are basically equivalent to what the consumer purchases at the retail level.     

猪肉色泽和保水性的相关性研究

以猪瘦肉为原料展开猪肉色泽和保水性之间的相关性研究,一部分以来源于同一猪胴体的肉样为原料,另一部分采用从市场上随机抽样的样品为原料,研究肉样的保水性和肉色之间的相关性。结果表明：对于来源于同一个体的肉样而言,保水性与色泽无关;而来源于不同个体的肉样,加压系水力(WHC)与亮度(L 值)呈负相关,蒸煮损失与L 值和黄度(b 值)呈正相关,即L 越大,b 越大,保水性越差;在实验测定的范围内,pH 值与蒸煮损失呈负相关,与加压系水力呈正相关,表明pH 值越高的肉样,保水性越好;来源于同一个体的肉样,随着宰后时间的延长,其保水性有增强的趋势,表现为蒸煮损失与时间呈负相关,加压系水力与时间呈正相关。     

Sodium Lactate/Sodium Tripolyphosphate Combination Effects on Aerobic Plate Counts, pH and Color of Fresh Pork Longissimus Muscle

The objective of this study was to evaluate the effects of sodium lactate/sodium tripolyphosphate pump combinations on the characteristics of pork loins. The product was manufactured to simulate fresh pumped pork loins currently available in the retail market. Paired fresh pork loins (longissimus muscle), pumped to contain 0, 1 or 2% sodium lactate (SL) and/or 0, 0·2 or 0·4% sodium tripolyphosphate (STP) were vacuum packaged and stored at 4°C for 28 days. In pork containing 0·4% STP, samples with 1 or 2% SL had lower pH values than those with 0% SL. Pork containing 1 or 2% SL generally had lower aerobic plate counts than those with 0% SL. Pork with 0·4% STP was darker (lower L* value) and redder (higher a* value) than that with 0 or 0·2% STP. When aerobic plate counts and color characteristics are used as the criteria, the optimum SL/STP combination for solutions used to pump fresh pork loins that are vacuum packaged and held under refrigeration was 1% SL with 0·2% STP.     

Hot Pork Processing, Brine Chilling and Mechanical Portioning as a Fresh Pork Processing System

Rapid chilling was investigated as a link between hot pork processing and mechanical portioning. Loins from market weight hogs (n = 40) were removed (pre- or post-rigor) and were assigned to one of two chilling treatments (brine chilling or blast freezing). Loins were chilled until crust frozen, then tempered, pressed and cleaved. Ultimate pH, cooking yields, taste panel ratings and Warner-Bratzler shear force values (WBS) were obtained. Pre-rigor chops had significantly higher WBS values and lower (less tender) taste panel ratings than post-rigor chops. Generally, pre-rigor chops were juicier but less tender. There were no major differences between rapid chilling treatments nor in ultimate pH or cooking data. Less severe chilling techniques are needed to make this processing system feasible.     

鲜猪肉中沙门氏菌生长预测模型的建立

以新鲜猪肉滤汁为培养液,接种沙门氏菌,绘制沙门氏菌在17、25、30、35、37℃下的生长曲线.一级模型分别使用Logistic和Baranyi模型拟合.二级模型以Ratkowsky方程为基础,代入Baranyi模型拟合数据,描述了温度对最大生长速率的影响.二级模型通过残差图、准确因子、偏差因子以及预测值与实测值对比图进行了检验,结果显示残差在±0.05之间,准确因子为1.0464,偏差因子为0.9933,预测值与实测值比较接近.     

鲜猪肉微冻保鲜技术的初步研究

本文主要研究鲜猪肉在-2℃下微冻保鲜过程中的质量变化,为其商业微冻保鲜提供理论依据。首先通过冻结曲线以测定鲜猪肉的冰点为-1℃,再确定其冻结点为-2℃,然后将鲜猪肉在-2℃下进行微冻保鲜试验,每隔3天测一次感官指标、理化指标(pH值、持水力、T-VBN)、微生物指标,并对各种指标进行综合比较分析,来探讨微冻保鲜技术在鲜猪肉中应用的可行性。结果表明:随着贮藏天数的增加,细菌总数和pH值以及持水力都呈现先降后升的变化趋势,并保持较低的细菌总数、T-VBN值,其贮藏期限可达20d以上。