Metabolite Profile Differences Among Different Storage Time in Beef Preserved at Low Temperature

Storage temperature influences meat color stability and quality. This study was performed to quality change‐associated metabolites profiles using a nontargeted liquid chromatography‐mass spectrometry (LC‐MS/MS)‐based method. Beef longissimus dorsi samples were purchased immediately after slaughter, and then stored at room temperature, 4 °C and 0 °C. Water holding capacity (WHC), moisture content and pH value of the muscle samples were detected. Muscle samples and quality control samples were then prepared for nontargeted LC‐MS/MS system, followed by identification of distinct metabolites. Pearson correlation coefficients between metabolites and quality indexes were calculated. Storage reduced pH values of beef, and room temperature and 4 °C displayed the lowest pH value. Moisture content and WHC in beef muscles, especially WHC declined obviously during the first 24 hr. The significantly altered metabolites profiles in meat samples at 0, 3.5, and 7 days during 4 °C storage were identified using LC‐MS/MS. Most metabolites showed linear changes during storage (0 to 7 days). Using Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis, we found 1(α)‐naphthol, urocanic acid, tyramine, guanine, histamine, picolinic acid, 4‐hydroxybenzaldehyde, and hypoxanthine were increased, and 2‐(S‐glutathionyl)acetyl glutathione and glutathione were decreased in beef during 4 °C storage. Correlation analysis showed there were significantly correlations between metabolites and meat quality indexes (WHC, moisture content, and pH). In summary, 1(α)‐naphthol, urocanic acid, tyramine, guanine, histamine, picolinic acid, 4‐hydroxybenzaldehyde, and hypoxanthine, proved to be harmful to human body, accumulated gradually, especially after 3.5 days during storage at 4 °C. While the contents of beneficial substances, including 2‐(S‐glutathionyl)acetyl glutathione and glutathione, were decreased, which provided reference for the nutrition guidance of using beef meat.     

Shelf life of case-ready beef steaks (Semitendinosus muscle) stored in oxygen-depleted master bag system with oxygen scavengers and CO2/N2 modified atmosphere packaging

This study aims to evaluate the stability of beef from Semitendinosus muscle packaged in oxygen permeable wrapped-tray units and stored in a master bag system, with and without oxygen scavengers. Changes in the atmosphere composition, microbiological indexes, myoglobin forms and color parameters were monitored during the storage in master bag, blooming and display life. The presence of scavengers reduced rapidly the oxygen concentration and maintained it at values not detectable instrumentally. Within few days of storage in master bags, the resolution of the transient discoloration was completed and the meat quality was maintained over the anoxic storage. After the removal from master bags meat bloomed completely reaching OxyMb level and Chroma values higher than those on fresh meat at t₀. During 48 h of display life at 4 °C, quality attributes had a decay slower than samples stored traditionally in air. Without scavengers the oxygen caused the irreversible discoloration within 7 days, due to the formation of metmyoglobin on the surface.     

挂面生产工序能力分析

为确定挂面生产线存在的质量波动和分析工序能力,测定生产过程中面团、面带、湿切面、干面条、成品挂面的质量性状.通过控制图分析其质量波动,计算受控工序的过程能力指数,确定质量波动点和过程能力不足的工序段.结果显示,监测18天内,面团水分含量和水分均匀度、面带③(压延结束后的面带)色泽a*值均匀度、成品挂面水分含量均有2次超出了控制图的控制限,面带③色泽a*值有3次,面条②(烘房二区运行后的面条)的水分含量有4次,干面条抗弯强度有6次超出了控制限;这7个指标存在异常质量波动.面带①(面团熟化复合形成的面带)的水分均匀度、面带②(二次熟化后的面带)的水分均匀度、面带③色泽L*值及其均匀度、面带③色泽b*值及其均匀度、挂面烹调时间及烹调损失均处于受控状态;面带①水分均匀度、面带③色泽b*值均匀度及挂面烹调损失过程能力指数分别为0.93、0.4和0.99,均小于1,工序能力不足.结果认为,挂面生产过程中,面团水分含量及其均匀度、面带③色泽a*值及其均匀度、干面条抗弯强度及成品挂面水分存在异常波动;面带①水分均匀度、面带③色泽b*值均匀度工序能力不足.     

Thermal transitions and extrusion of glycerol-plasticized whey protein mixtures

ABSTRACT:  The effects of glycerol and moisture contents on the thermal transitions of whey protein isolate (WPI) powder–glycerol–water mixtures were studied. Mixtures with ratios of 100:0, 70:30, 60:40, and 50:50 WPI:glycerol on a dry basis (db) were preconditioned to 0.34 ± 0.01 (25.4 ± 0.4 °C) and 0.48 ± 0.02 (25.9 ± 2.2 °C) water activity. Differential scanning calorimetry (DSC) showed the existence of an endothermic peak starting at 148.3 ± 0.7 °C for 100% WPI preconditioned to a water activity of 0.34 ± 0.01. The onset temperature of this peak decreased with addition and increase of glycerol content, as well as with the increase in water activity from 0.34 ± 0.01 to 0.48 ± 0.02. An additional endothermic transition, important for extruding the mixtures into flexible sheets, occurred in mixtures containing 50% glycerol db, preconditioned to 0.48 ± 0.02 water activity. The onset temperature of the peak was 146 ± 2.0 °C. Whey protein-based sheets containing 45.8%, 48.8%, and 51.9% glycerol db were obtained using a Haake–Leistritz corotating twin-screw extruder. All samples were obtained at a screw speed of 250 rpm and a final barrel-temperature profile of 20, 20, 20, 80, 110, and 130 °C. Melt temperature at the time of sheet formation was 143 to 150 °C. Average thickness of the sheets was 1.31 ± 0.02 mm. Samples with 45.8% glycerol db had significantly higher tensile strength (TS) than samples with higher glycerol contents. Also, as glycerol concentration increased, sheet elastic modulus (EM) decreased significantly ( P ≤ 0.05). Extrusion of whey protein-based sheets is an important step toward extrusion of thinner edible films for food wraps, layers, or pouches.     

Comparison of Color and Thiobarbituric Acid Values of Cooked Hamburger Patties after Storage of Fresh Beef Chubs in Modified Atmospheres

ABSTRACT: Cooked meat color is an important quality attribute for consumers. This study compared color and thiobarbituric acid (TBA) values of cooked ground beef (internal temperatures of 49 to 79 °C), after storage of raw product in atmospheres of 0.4% carbon monoxide (CO), 80% oxygen, or vacuum at 2 °C for 7 to 21 d. Premature browning, observed as a brown cooked color at internal temperatures as low as 49 °C, was found in patties made from meat stored in 80% oxygen. At all cooking temperatures, samples stored in high oxygen had less internal red color, higher myoglobin denaturation values, and were more rancid with higher TBA values than CO or vacuum-packaged ground beef. Raw ground beef held in 0.4% CO modified-atmosphere packaging (MAP) remained bright red throughout the 21-d storage period. Premature browning and high TBA values in cooked patties were avoided by use of this packaging system. However, internal patty color remained somewhat red even at the highest internal cooking temperature of 79 °C. The persistent pink color observed in CO-treated patties cooked to 79°C internal temperature was likely due to development of heat-denatured CO-hemochrome, rather than the presence of undenatured CO myoglobin. The problems of PMB and high TBA values of cooked patties were also avoided by vacuum packaging. However, the development of dark purple color associated with vacuum packaging of raw beef limits the use of this packaging method for products in retail display. Keywords: beef, packaging, carbon monoxide, oxygen     

Microbiological and physicochemical properties of fresh retail cuts of beef packaged under an advanced vacuum skin system and stored at 4 degrees C

The effect of an advanced vacuum skin packaging system on the microbiological and physicochemical properties of fresh retail cuts of beef (including meat portions from six different anatomical regions) stored at 4 degrees C was compared with the effect of traditional vacuum packaging. The vacuum skin packaging system whose effect on meat quality was evaluated in this work displayed two remarkable features: (i) the instantaneous heating of the lower surface of the upper film of the package before the film descended over the meat surface and (ii) the tight disposition of the plastic film on the meat surface, which avoided wrinkles and purges. Throughout storage at 4 degrees C, rates of bacterial growth were statistically significantly slower in beef portions processed with the vacuum skin packaging system than in those processed with traditional vacuum packaging, with average differences of 2.07, 1.60, and 1.25 log CFU/g in counts of aerobic mesophiles, anaerobes, and lactic acid bacteria, respectively. pH values were statistically significantly lower for beef portions packaged with the vacuum skin system than for those that were vacuum packaged in the traditional manner, probably because of the relative predominance of lactic acid bacteria observed in such samples, which coincided with both higher meat firmness values and a slower meat tenderization process. The vacuum skin system prevented the appearance of undesirable coloration on the meat surface and also significantly improved the commercial color of the meat as determined on the basis of luminosity (L*) and the redness (a*). Overall, the quality (as determined by microbiological and physicochemical analyses and by visual examination) of fresh retail cuts of beef packaged with the vacuum skin system and stored at 4 degrees C was higher than that of meat samples processed with the traditional vacuum-packaging system.     

原料肉部位对牛干巴肉质特性的影响

选取（30±2） 月龄云岭去势公牛6头,屠宰后经7d低温（0～5 ℃）排酸,精细分割后各取500 g西冷和针扒2 个部位原料肉进行肉质分析。采用腌制、烤干工艺将原料肉加工成牛干巴,测定原料肉和牛干巴水分、粗蛋白、粗脂肪、灰分含量、失水率、蒸煮损失率、pH值、总挥发性盐基氮（total volatile basic nitrogen,TVB-N）含量、亚硝酸盐含量、剪切力、肉色和氨基酸含量。结果表明：西冷和针扒2 个部位原料肉的粗蛋白含量、粗脂肪含量、灰分含量、剪切力和黄度值（b*）差异显著（P＜0.05）,水分含量、失水率、蒸煮损失率和亮度值（L*）、红度值（a*）差异不显著;加工成牛干巴后,2 个部位水分含量、粗脂肪含量、粗蛋白含量、剪切力和L*存在显著差异（P＜0.05）,灰分含量、b*和a*差异不显著,pH值、TVB-N含量、亚硝酸盐含量均在合理范围内;牛干巴氨基酸含量高于原料肉,原料肉总氨基酸（total amino acid,TAA）、必需氨基酸（essential amino acid,EAA）、非必需氨基酸（non-essential amino acid,NEAA）含量差异均不显著,牛干巴TAA、EAA、NEAA含量均差异显著（P＜0.05）;原料肉西冷的剪切力、肌间脂肪指标均优于针扒,经相同工艺制成牛干巴后,嫩度、脂肪含量受原料肉品质影响较大。     

Color, lipid oxidation, sensory quality, and aroma compounds of beef steaks displayed under different levels of oxygen in a modified atmosphere package

High oxygen modified atmosphere packaging (MAP) is currently used by the industry to maintain an attractive color in fresh meat. However, it can also promote lipid oxidation and sensory changes. The aim of this study was to compare the quality of beef steaks displayed under different levels of oxygen. For that purpose, meat was stored with 50%, 60%, and 80% of oxygen for 4 and 8 d at retail conditions. A control treatment with steaks vacuum packaged, without exposure to retail display, was included, and color, lipid oxidation, organoleptic characteristics, and aroma compounds were analyzed. Steaks displayed under high oxygen MAP with 50% of oxygen showed the lowest color stability, according to hue values. Higher oxygen levels did not necessarily correspond with higher rancidity levels in the raw meat. Thiobarbituric Acid Reacting Substances (TBARS) values were higher than 2.2 mg malonaldehyde (MDA)/kg muscle in all the samples displayed for 8 d at retail conditions. These samples exhibited the highest intensities of rancid and the least intense beef odors and flavors. The ketones: 2,3-butanedione, 2-octanone, 2,3-pentanedione, 2-heptanone, 4-methyl-2-pentanone, and the aldehydes: pentanal, 2-methyl-butanal, and 2-furfurylthiol, 1-octen-3-ol and 2-methylpropyl-acetate, were proposed as candidates for the aroma differences between the cooked beef steaks stored under vacuum and high oxygen packs. PRACTICAL APPLICATION: High oxygen modified atmosphere packaging (MAP) is used to increase shelf-life and color at the retail level. However, oxygen deteriorates faster some quality attributes, being a contributor to lipid oxidation that could be perceived at consumption. This study attempts to find the best gas composition in a MAP in order to maintain the color, minimizing the oxidation. Aromatically relevant chemicals have been analyzed by gas olfactometry-gas chromatography as a key to measure beef oxidation after display.     

Use of sodium caseinate/glycerol edible films to reduce lipid oxidation in sliced turkey meat

The objective of this study was to investigate the influence of sodium caseinate films containing glycerol [glycerol:protein ratio 0.32 (w/w)] on lipid oxidation in cooked turkey breast meat slices. Slices were wrapped in films of different thickness (22, 42, and 58 μm) and were stored at 4 °C for 1, 2, 3 and 4 days. Lipid oxidation was measured using TBARS and hexanal assays on each day of storage while an olfactory sensory analysis was carried out on all the samples after 4 days of storage. TBARS values and hexanal levels of unwrapped samples (~6.0 mg MDA/kg and ~8.0 mg hexanal/kg) were significantly (P ≤ 0.05) higher than those of the casein film wrapped samples (~3.0 mg MDA/kg and ~3.0 mg hexanal/kg). Sensory analysis also showed significant (P ≤ 0.05) differences between wrapped samples and unwrapped samples, the former being perceived as less rancid. Thus wrapping in caseinate films may help reduce lipid oxidation in cooked turkey meat.     

Low-temperature osmotic dehydration improves the quality of intermediate moisture meats

Dehydration of meat at low temperature (4°C) with a new dehydrating sheet to obtain intermediate moisture meat produced more desirable results than did more rapid dehydration at 25°C, because the native state of meat proteins was better retained at the lower temperature. At low temperature with replacement of the dehydrating sheet once per day, the water content decreased to 57% after 150 h. Water activity (a(w)) dropped to 0·965. Myofibrils could be prepared readily from meat after 150 h at 4°C, and the myofibrils were induced to contract by addition of Mg(2+)-ATP solution and therefore retained biological activity. Electron microscopic observation showed that intermediate moisture meat prepared at 4°C retained the original muscle structure to a large extent. Myosin could be extracted easily from intermediate moisture meat dehydrated at 4°C after 10 days of storage at 25°C. No marked difference in the effect of dehydration on muscle was observed among species (beef, pork, chicken and rabbit). Results show that dehydration at low temperature (4°C) with use of the new dehydrating sheet enables intermediate moisture meat of good quality to be manufactured.     

A review of natural antioxidants and their effects on oxidative status, odor and quality of fresh beef produced in Argentina

Meat derived from pasture feeding, is associated with a high level of antioxidants. Antioxidants are incorporated within cell membranes and protect tissues against oxidation from reactive oxygen species. This maintains the overall quality of meat and secondary products. This paper reviews the implications of incorporating natural antioxidants into fresh beef, focusing on the benefits of feeding cattle good quality pasture. Pasture samples typically have higher levels of α-tocopherol, β-carotene, ascorbic acid and glutathione than feedlot samples. These compounds retard lipid and protein oxidation in fresh and stored meat, and preserve the color and odor quality of beef. The significance of antioxidant enzymes is variable, because their behavior depends on individual redox status before slaughter. Understanding total antioxidant activity requires information on antioxidant and pro-oxidant status. With an abundance of pasture, Argentina has a natural advantage in producing meat with a high antioxidant value.     

Characteristics of some intermediate moisture smoked meats

Intermediate moisture smoked beef was prepared by cook-soak/equilibration in a solution containing sodium chloride, sodium nitrite and potassium sorbate. Two further solutions contained glycerol and glycerol + 'onion' in addition to the above ingredients. Half the samples in each treatment group were smoked for 18 h (heavy smoking) and the others for 4 h (light smoking) at 50°C. All samples developed the pink-red colour of nitrite cured meat but those treated with glycerol were darker, presumably due to decreased moisture contents. Glycerol increased the apparent moisture, fat and sodium dodecyl sulphate (SDS) soluble protein contents and also improved the conversion of haemoproteins to the cooked cured form but decreased the percent soluble hydroxyproline. Smoking caused a marked decrease in moisture, SDS-soluble protein and soluble hydroxyproline contents and slightly decreased the available lysine and percent conversion of the haemoproteins to the cured nitrose forms. Smoking also caused increased darkening and hardness of the samples. Total viable aerobes, coliforms and fungi were below the levels of detection while TBA values were low and all samples possessed no detectable rancidity. Electrophoretograms of the samples indicated that cooking/equilibration had no significant effects on the proteins present but smoking led to a slight loss of some of the protein components.     

牛肉品质快速检测装置的设计

目的 开发基于可见/近红外光谱技术的牛肉品质快速检测系统。方法 利用波长范围为400~2600 nm的光谱仪为核心检测部件, 结合控制器、光源、光纤等辅助装置构成了检测系统的硬件部分, 对32个牛肉通脊样本进行检测, 并用肉类嫩度仪进行验证。结果 27个样本为嫩肉, 5个样本为粗糙肉, 嫩度检测正确率为100%。结论 该装置能够对牛肉的嫩度品质进行较准确的检测。     

Evaluation of the performance of osmotic dehydration sheets on freshness parameters in cold-stored beef biceps femoris muscle

This study aimed to evaluate the effects of osmotic dehydration sheet (ODS) packaging on the quality parameters of beef biceps femoris muscle samples stored at 4 °C for 0, 1, 3 and 7 days. Quality indices such as Hunter color values (L^∗, a^∗ and b^∗, the percentage of metmyoglobin (Met-Mb%), K value (freshness index), and the contents of adenosine triphosphate (ATP)-related compounds (ARCs), thiobarbituric acid reactive substances (TBA-RS) and volatile basic nitrogen (VBN) were measured. ODS gave lower a^∗ and b^∗ values and lower Met-Mb% compared with control samples wrapped in polyvinylidene chloride film (PVDCF) (P < 0.01), but had no effect on L^∗ (P < 0.01). As a result, with higher levels of osmotic dehydration produced by the ODS, the percentage of weight loss and the total contents of ARCs and inosine monophosphate of the samples also increased (P < 0.05). The K values of ODS samples were also significantly lower than PVDCF-wrapped samples (P < 0.05). Low performance ODS wrapping reduced the TBA-RS values below those found with PVDCF and high performance ODS processing (P < 0.01). Moreover, the use of ODS had no effect on VBN values. Thus, although the bright red of beef samples changed to a dark purple color and the weights of samples decreased, the ODS approach has potential as a tool for decreasing the deterioration of other quality indices such as Met-Mb%, TBA-RS, ARCs, K values and the VBN content of cold-stored beef.     

TEXTURAL CHANGES IN INTERMEDIATE MOISTURE MEAT DURING STORAGE AT 38°C

Intermediate moisture beef prepared by cook-soak equilibration, with glycerol and sodium chloride as humectants, was stored at 38°C under both anaerobic and aerobic conditions for up to 12 weeks. Meat texture was measured by Warner-Bratzler, tensile and objective texture profile methods. Covalent crosslink formation was monitored by solubility measurements in solutions of sodium dodecyl sulphate plus β-mercaptoethanol.
A decrease in the Warner-Bratzler peak height on storage was observed though this did not depend strongly on the storage environment. In contrast, the large decrease observed in the tensile force required to rupture the meat when pulling perpendicular to the fibre direction was greater for aerobically stored meat. The cohesiveness and 'elasticity' of the meat as determined by objective texture profile measurements showed an initial decrease followed by a subsequent increase, but a similar increase was not shown by the hardness parameter. The results are discussed in terms of the crosslinking and degradative reactions known to occur in meat of this type.     

Effect of Laser trilobum spice on natural microflora of k?fte, a Turkish ground meat product

The effect of Laser trilobum spice on natural microflora of "k?fte", a Turkish ground meat product, prepared using three beef samples and stored at 7 degrees C and 20 degrees C was evaluated. Little or no inhibition was seen in all products and temperatures with 1.0% spice. Growth of natural microflora, namely total viables, coliforms, psychrotrophs and yeasts-moulds, was significantly inhibited by 2.0% of the spice, especially at 7 degrees C. The inhibitory effect of the spice increased with decreased fat content and increased water and protein contents of beef samples. It was concluded that the usual addition of the spice improved the hygienic quality of the product containing low fat and stored at 7 degrees C.     

大豆分离蛋白-脂质涂层对冷却牛肉品质的影响

研究脂质(硬脂酸、棕榈酸、巴西棕榈蜡和三乙酸甘油脂)与大豆分离蛋白制成的可食性涂层对冷却牛肉品质的影响。考察冷却牛肉在4℃下贮藏108h过程中失重率、颜色、pH值、硫代巴比妥酸值和感官特性的变化。结果表明冷却牛肉在4℃贮藏时的货架期小于108h,而且在4℃贮藏84h后,不同大豆分离蛋白-脂质涂层的优点不同。其中,三乙酸甘油酯蛋白涂层不仅延缓冷却牛肉的氧化,而且有效维持其感官特性,对维持冷却牛肉品质和延长期货架期效果最佳。     

蒸制时间对牦牛肉品质影响的模型构建与分析

以蒸制牦牛肉为研究对象,将初始条件一致的牦牛肉在相同温度(100℃)条件下分别蒸制40、60、80、100、120 min,之后对不同蒸制时间下的牛肉嫩度、保水性、p H、色泽、蛋白质含量、脂肪含量、水分含量等品质指标进行测定,同时利用主成分分析(principal component analysis,PCA)法结合感官评定构建蒸制牦牛肉的品质评价模型并结合模糊数学法对感官评分进行综合比较。结果表明:牦牛肉色泽、嫩度、保水性受蒸制时间影响变化较显著(p0.05),蒸制60 min较适于传统牦牛肉蒸制工艺,在此条件下的牛肉剪切力为5.33 kg,色彩值为12.15,WHC为91.45%,均为最佳,其蛋白质含量为37.01%,脂肪含量为3.71%,水分含量为57.80%,均较正常。运用PCA法所建模型的第一、二主成分特征根均大于1,累计贡献率达到86.469%,可以较好地反映蒸制牛肉品质指标构成的原始信息。该模型判断出不同蒸制时间的蒸制牛肉品质优劣顺序为:60 min80 min40 min100 min120 min,与模糊数学感官评分结果呈极显著正相关(p0.01),进一步证实了此模型的客观可靠性。     

Comparison of the Real-time Microrespirometer and Aerobic Plate Count Methods for Determination of Microbial Quality in Ground Beef

ABSTRACT Real-time microrespirometer measurements were compared with the aerobic plate count (APC) method to assess microbial quality of ground beef stored at 4°C and 7°C with and without previous freezing. The samples were monitored daily for CO2 evolution rate (CER) using a microrespirometer, APC, and were evaluated for color and odor changes by a sensory panel. The CER was highly correlated with the APC for all storage conditions ( r 2 = 0.787 to 0.952). The onset of meat spoilage was more closely associated with a specific CER value (>25 μL/h/g) than APC. The new method was found to be more accurate in predicting meat spoilage, especially for previously frozen samples.     

Effect of erythorbic acid on cooked color in ground beef

Consumers often use the color of cooked ground beef as an indicator of doneness. For safety reasons, it is recommended that the center of ground beef products be heated to 71°C. In some instances beef may appear done before reaching 71°C, a condition termed premature browning (PMB). Ground beef (15% fat), with added erythorbic acid (ERY) at 0.04 and 0.06% was formed into patties, wrapped in oxygen permeable film, and stored in the dark at 4°C. Patties were stored for either 10 h or 58 h and then cooked to internal end point temperatures of 60, 66, 71 or 77°C. Internal cooked color L(?), a(?) and b(?) values were measured. For beef patties stored 10 h, there was no effect of ERY on internal cooked color. After 58 h storage, ground beef with 0.04 and 0.06% ERY had higher a(?) values than controls at 60°C (P<0.05). Beef with 0.04% ERY cooked to an internal temperature of 66°C had higher a(?) values than 0.06% ERY and controls (P<0.05). There was no effect of ERY on color of beef patties cooked to 71 or 77°C. The presence of 0.04% ERY in ground beef patties stored 58 h appeared to maintain red color at internal temperatures of 60 and 66°C.