禁食时间对宰后早期鸡肉持水力和嫩度的影响

三黄鸡分别禁食0、8、16h和24h,三管齐断法宰杀,于宰后5h内分别测定滴水损失、蒸煮损失、加压损失、蛋白溶解性、剪切力值、糖原、乳酸和pH值等指标,观察禁食对宰后早期鸡肉持水力和嫩度的影响。结果表明：随着禁食时间延长,宰后糖原含量(P＜0.05)和pH值均降低;随着宰后时间延长,糖原含量和pH值变化趋势与宰后时间正相关,而乳酸含量变化趋势与宰后时间负相关。宰后早期,pH值对肌肉持水力有显著影响(P＜0.05),而蛋白溶解度对持水力变化贡献不大。禁食使得宰后早期肌肉剪切力值有增大趋势,但处理组之间差异不显著。与未禁食鸡相比,禁食8h和禁食16h能够提高宰后肌肉持水力。     

鸡肉类PSE肉与正常肉流变、质构特性的比较

以亮度值(L*)与屠宰24h后的pH值(pH24h)作为区分类PSE肉与正常鸡肉的指标,对两者肉糜的流变特性、质构特性和蒸煮损失进行研究。结果表明:具有低pH24h、高L*值的类PSE肉,在流变性、蒸煮损失和质构上存在显著差异。类PSE肉的流变曲线趋势异于正常肉,表现出低的贮能模量和大相位角正切值(P<0.05),极值所对应的温度低于正常肉(P<0.05);类PSE的蒸煮损失高于正常肉(P<0.05),硬度、弹性、黏聚性、咀嚼性和回弹力显著低于正常肉。鸡胸肉的pH值和L*值与其肉糜的质构与流变特性密切相关,是分析和控制类PSE对深加工产品影响的重要参考因素。     

宰后贮藏过程中羔羊肉食用品质的变化

研究宰后不同时间羔羊肉食用品质的差异。以羔羊背最长肌为研究对象,测定4℃贮藏条件下,宰后不同时间(1、6、12、24、72、120、168 h)羔羊肉中心温度、菌落总数、pH值、肌节长度、剪切力、肉色、肌红蛋白相对含量和蒸煮损失的变化。结果表明:宰后羔羊肉的pH值从宰后1 h的6.45下降到宰后120 h的5.40左右;宰后1 h和6 h羔羊肉的肌节长度无显著变化(P0.05),宰后12 h最短,宰后24 h后开始变长,而宰后120、168 h变化不显著(P0.05);羔羊肉亮度值(L*)随宰后时间的延长呈上升趋势,红度值(a*)和黄度值则先升高后降低,且氧合肌红蛋白相对含量与a*变化规律一致;羔羊肉剪切力呈现先上升后下降的趋势,在宰后12 h达到最大;宰后1 h羔羊肉的蒸煮损失最低,随后不断增加,168 h时达到最大。综上,宰后6 h前的羔羊肉处于僵直前期,宰后6～24 h时处于僵直期,宰后24～120 h处于解僵期,宰后120 h时解僵过程完成;僵直前和解僵后羔羊肉的食用品质存在差异,僵直前羔羊肉的保水性较高,成熟后羔羊肉的嫩度较高,L*和a*较高。     

冷却鸡肉保水性评定指标标准化及其与肉色、嫩度和pH24 h相关性研究

对鸡肉不同保水性测定指标（蒸煮损失、滴水损失和压榨损失）的处理条件和操作规程进行统一标准化,同时探讨保水性各指标之间及与肉色、宰后24 h pH值（pH24 h）的相关关系。结果表明：滴水时间对滴水损失有显著影响（P＜0.05）;压力大小和加压时间对压榨损失有显著影响（P＜0.05）;水浴温度和中心温度对蒸煮损失影响显著（P＜0.05）。根据实验结果以及实际工艺的要求各指标测定条件推荐为：滴水损失肉块大小为2 cm×2 cm×2 cm、滴水时间为48 h;压榨损失压力大小为35 kg、加压时间为5 min;蒸煮损失水浴温度为75 ℃、肉样中心温度为70 ℃。相关性分析结果表明：剪切力值与蒸煮损失呈显著正相关（P＜0.05）;pH24 h值与亮度（L*）值呈极显著负相关（P＜0.01）,与压榨损失和滴水损失呈显著负相关（P＜0.05）;滴水损失与其他保水性指标之间均存在显著相关性。pH24 h值在一定程度上影响肉色和保水性,滴水损失可作为保水性的最佳指示参数。     

宰后成熟程度对扒鸡嫩度和保水性的影响

研究宰后成熟不同时间对扒鸡胴体指标的变化规律以及对扒鸡嫩度和保水性的影响,以4℃下成熟0～24 h的鸡胴体以及扒鸡为研究对象,测定其p H值、出品率、蒸煮损失率、加压失水率、水分含量、剪切力值、质构特性的变化规律。鸡胴体的p H值呈先下降后上升的趋势,蒸煮损失率和剪切力值、加压失水率则是先上升后下降,p H值与加压失水率呈极显著负相关(P <0. 01)。扒鸡经过宰后成熟,出品率得到提高;不同宰后成熟时间,扒鸡的p H值和加压失水率数值变化范围不大,水分含量在2～6 h比较大。鸡胴体经过宰后成熟,可以提高扒鸡出品率,改善鸡肉的嫩度和保水性。综合各项指标结果及工厂的经济效益考虑,确定扒鸡最适成熟程度为4℃下成熟2 h。     

不同质量等级的中国黄牛肉在成熟过程中的品质变化研究

选取优一级、优二级和普通级中国黄牛牛胴体的外脊,测定其在成熟0、1、3、7、14、21和30h的剪切力值、pH、解冻滴水损失、蒸煮损失和熟肉率。结果表明,等级和成熟时间对外脊剪切力值有显著影响(p<0.05),等级对解冻滴水损失、蒸煮损失和熟肉率有极显著影响(p<0.01)。在同一成熟时间,级别越高,剪切力值越小,解冻滴水损失和蒸煮损失越小,熟肉率越高;随着成熟时间的延长,牛肉的剪切力值显著降低,解冻滴水损失和蒸煮损失显著增大(p<0.01)。     

冷藏时间对冷却猪背最长肌品质的影响

以宰后24 h的猪背最长肌为研究对象,研究4 ℃条件下冷藏0、12、24、36、48 h对猪背最长肌pH值、色 差、冷藏损失、蒸煮损失、剪切力和水分迁移状态的影响。结果表明：随着冷藏时间的增加,猪背最长肌的pH 值、黄度值（b*）、冷藏损失率和蒸煮损失率均显著提高（P＜0.05）;亮度值（L*）和红度值（a*）在冷藏24 h 内差异不显著（P＞0.05）;冷藏48 h时,猪背最长肌的pH值、L*、b*、冷藏损失和蒸煮损失最大,剪切力最小; 低场核磁共振结果表明,随着冷藏时间的增加,T2b、T21和T22起始弛豫时间显著延长（P＜0.05）,T21的峰面积比例 降低,T22的峰面积比例增加。综上所述,4 ℃条件下冷藏24 h以内有利于保持猪背最长肌的品质。     

宰前碳酸水处理对猪肉品质的影响

试验通过对生猪宰前禁食期间饮用不同时间的碳酸水,研究碳酸水处理对宰后猪肉品质的影响。结果表明:通过宰前禁食期间碳酸水处理,对猪宰后不同时间测定的pH值都具有显著影响(P<0.05),且宰前饮用120min碳酸水时最终pH值有所偏高;禁食期间饮用碳酸水对宰后猪肉的色泽和持水力、剪切力值无显著影响(P>0.05),但对宰后猪肉的蒸煮损失均有显著影响(P<0.05),其试验组相比宰前饮用60min碳酸水时宰后猪肉的蒸煮损失最小,因此,宰前禁食期间饮用60min碳酸水时,猪肉品质最佳。     

不同腌制方式对鸭肉腌制速率及肉质的影响

为探讨真空度和压力值对鸭肉腌制速率和肉质的影响,以常压腌制为对照,分别探讨了脉动真空、脉动加压、真空加压三种腌制方式对鸭肉腌制速率、pH值、蒸煮损失、剪切力和腌制液中蛋白含量的影响。结果表明:在腌制6 h后常压、脉动真空、脉动加压、真空加压的盐分含量分别为2.61%、3.01%、2.91%、3.21%。四种腌制方式下鸭肉pH值有所降低,但差异性不显著(p0.05)。脉动真空、真空加压腌制比常压腌制的蒸煮损失低,而脉动加压的蒸煮损失却高于常压腌制。在腌制4 h后,常压、脉动真空、脉动加压、真空加压腌制后的鸭肉的剪切力是分别是1076 g、938 g、1093 g、908 g,其中脉动真空、真空加压腌制与常压腌制的剪切力差异显著(p0.05),脉动加压腌制与常压腌制的剪切力不显著(p0.05)。三种腌制方式的腌制液中的蛋白含量均高于常压腌制(p0.05)。综合比较真空加压腌制在腌制速度和对肉质改善方面优于脉动真空和脉动加压腌制。     

冻融次数对牦牛肉胶原蛋白特性及品质的影响

为探究冻融次数对牦牛肉胶原蛋白特性和品质的影响。以牦牛肉为研究对象,分析不同冻融次数下牦牛肉剪切力、pH、解冻损失、蒸煮损失、色差、质构、胶原蛋白含量及溶解性、酶活性及微观结构的变化规律。结果表明,随着冻融次数的增加,牦牛肉剪切力下降了59.72%,牦牛肉胶原蛋白溶解性、β-半乳糖苷酶和β-半乳糖醛酶活力、解冻损失、蒸煮损失和b^*值显著上升(P<0.05),胶原蛋白含量、剪切力、pH、L^*值、a^*值以及质构显著下降(P<0.05)。相关性分析表明:剪切力与L^*值、a^*值、pH、胶原蛋白含量和溶解性、质构指标呈显著正相关(P<0.01),与解冻损失、蒸煮损失、b^*值、β-半乳糖苷酶活性和β-葡糖醛酸酶活性呈极显著负相关(P<0.001);pH与胶原蛋白特性呈极显著正相关(P<0.001);胶原蛋白特性与质构指标呈极显著正相关(P<0.001)。牦牛肉组织结构随冻融次数增加表现为破坏严重,肌纤维边界模糊。综上,冻融次数增加,...     

不同冷却方式及涂膜种类对鸡肉品质的影响

研究不同冷却方式涂膜种类对鸡肉品质的影响。采用普通冷却、二阶段冷却、真空冷却3种不同冷却方式对海藻酸钠及壳聚糖涂膜鸡肉进行处理,然后对冷却肉的肉色、剪切力等指标进行测定。结果表明:鸡肉经过涂膜后再冷却处理,感官明显得到改善;二阶段冷却处理后鸡肉的剪切力值最低,涂膜处理可提高肉的嫩度;经涂膜处理后再进行冷却能显著降低鸡肉的冷却质量损失率、汁液损失率及蒸煮损失率;冷却及涂膜处理对鸡肉的pH值影响不显著(P0.05)。因此,涂膜处理能有效地防止鸡肉冷却过程中引起的干耗、色泽暗淡、pH值下降等问题,改善肉的品质,冷却方式中二阶段冷却最佳。     

Quality Characteristics of Broiler Chicken Meat on Salt at Different Temperatures

The aim of this investigation was to compare the quality characteristics and muscle structure of broiler chicken meat stored at different temperatures in the retail market in Oman. The meat quality characteristics of broiler breast meat were analysed. Ten samples were randomly selected from each group of fresh, frozen, and chilled chicken meat. Colour L?, a?, b?, pH, expressed juice, cooking loss, sarcomere length, W-B-shear force and muscle structure (using scanning electron microscopy) were determined. Fresh meat samples had significantly (P < 0.05) lower pH values and lightness L? than those of chilled and frozen samples. The chilled meat samples were significantly (P < 0.05) lighter and had lower shear force values than fresh and frozen samples. Frozen samples had significantly (P < 0.05) higher expressed juice and cooking loss values than either fresh or chilled samples. The pH values of fresh, chilled, and frozen breast samples were related to colour and expressed juice. Electron microscopy demonstrated that the changes in the physical properties of the chilled meat were related to breakdown of the muscle fiber bundles. The quality characteristics of broiler meat from different storage temperatures varied significantly.     

Effect of chilling applied to suckling lamb carcasses on hygienic, physicochemical and sensory meat quality

The effect of post mortem temperature treatment on suckling lamb carcass and meat quality was study. Conventional (2°C for 24h), ultra-rapid (-20°C for 3.5h, 2°C until 24h) and slow chillings (12°C for 7h, 2°C until 24h) were compared. Total viable counts (TVC), weight losses, and pH and temperature falls were recorded on carcasses. Meat colour, water holding capacity (WHC), Warner-Bratzler shear force, sarcomere length and sensory analysis were evaluated in M. longissimus. Ultra-rapid treatment reduced TVC and weight losses. The pH decline was faster in slow chilled carcasses than in faster chilled carcasses. No significant differences were found for colour and WHC. Slow treatment carcasses showed significantly lower shear force and higher sarcomere length. In the sensory analysis, tasters also rated the early post mortem slow-treated meat as more tender, less fibrous and chewy. Therefore, delay chilling in suckling lamb carcasses made it possible to obtain meat with better organoleptic characteristics, without affecting weight loss or hygienic quality.     

Effect of frozen storage of minced meats on the quality of sausages prepared from them

Mutton, pork and beef sausages were prepared from minced meats which had been frozen and stored up to 52 weeks at -18°C. There was a significant decrease in texture (W-B shear force) of all the sausages with increased age of the meat. However, concomitantly there were no significant differences in the colour, juiciness or shrinkage (cooking loss) of the sausages. All sausages were organoleptically acceptable even when made from meats stored for 52 weeks at -18°C.     

The influence of ante-mortem treatment on relationship between pH and tenderness of beef

Longissimus lumborum et thoracis muscles from 150 cattle comprising Czech Pied breed bulls and cows were used to investigate the relationship between pH value and beef tenderness as influenced by housing before slaughter and by the hanging mode of carcasses. The pH value was measured in the loin at the end of the slaughter-line (pH(0)) and after cooling of carcasses (pH(24),pH(48)). The texture of raw meat was measured 72h post-mortem by the Warner-Bratzler shear method; the shear force was related to pH. Curvilinear relationships with coefficients of correlation r=0.64 (P<0.05) for bulls individually housed and r=0.83 for bulls housed in groups between the shear force and the pH value 24h p.m. were found with maximal shear force (the most tough meat) in the range of pH(24) from 6.2 to 6.4. Lower correlations (r=0.72 and r=0.54) between pH(24) and meat tenderness were found in the case of cows individually housed and housed in groups, respectively. No significant relationships were found between texture and pH measured at the end of the slaughter-line (r=0.59 for bulls and r=0.65 for cows) and 48h post-mortem (r=0.64 for bulls and r=0.50 for cows). The mode of housing of cattle before slaughter influenced the properties of beef significantly. Meat of bulls housed in groups before slaughter was less tender (the shear force was higher) than meat of bulls individually housed. It could be explained by higher depletion of glycogen before slaughter and thus insufficient pH decline. Generally, the meat of cows was more tender than of bulls irrespective of housing. No significant differences were found between the left and right halves of carcasses. Thus the mode of hanging had no influence on beef tenderness.     

优质鸡肉质性状相互关系的研究

本试验研究了优质鸡胸肌和腿肌肌肉性状间的相互关系,并对肉质性状进行了主成分分析。结果表明,肌肉IMF与pH1、pH2、肌纤维密度呈正相关,而与烹饪损失、肌肉剪切力、肌纤维直径呈负相关。肌肉pH与烹饪损失、剪切力、肌纤维直径呈负相关,而与肌纤维密度呈极显著正相关。滴水损失与烹饪损失、肌纤维密度呈负相关,而与剪切力、肌纤维直径呈正相关。肌肉烹饪损失、剪切力与肌纤维直径呈正相关,而与肌纤维密度呈显著负相关。另外,主成分分析表明,胸肌肉质性状可以用4个主成分因子进行表示,腿肌肉质性状可以用2个主成分因子进行表示。     

Validation of a Combi Oven Cooking Method for Preparation of Chicken Breast Meat for Quality Assessment

ABSTRACT: Quality assessment results of cooked meat can be significantly affected by sample preparation with different cooking techniques. A combi oven is a relatively new cooking technique in the U.S. market. However, there was a lack of published data about its effect on quality measurements of chicken meat. Broiler breast fillets deboned at 24‐h postmortem were cooked with one of the 3 methods to the core temperature of 80 °C. Cooking methods were evaluated based on cooking operation requirements, sensory profiles, Warner–Bratzler (WB) shear and cooking loss. Our results show that the average cooking time for the combi oven was 17 min compared with 31 min for the commercial oven method and 16 min for the hot water method. The combi oven did not result in a significant difference in the WB shear force values, although the cooking loss of the combi oven samples was significantly lower than the commercial oven and hot water samples. Sensory profiles of the combi oven samples did not significantly differ from those of the commercial oven and hot water samples. These results demonstrate that combi oven cooking did not significantly affect sensory profiles and WB shear force measurements of chicken breast muscle compared to the other 2 cooking methods. The combi oven method appears to be an acceptable alternative for preparing chicken breast fillets in a quality assessment.