肉及肉制品中彩虹色斑点现象的调查分析

彩虹色斑点是近年来发现存在于肉及肉制品中的一种非正常颜色。对我国几家大型屠宰场的猪、牛分割肉及南京各大超市销售的部分肉制品进行了调查,结果表明:猪肉的各部位均无彩虹色斑点现象;牛肉半腱肌中彩虹色斑点的发生率为83%,其他部位从高到低分别为背最长肌(21%),腰大肌(7%),股二头肌(5%)。牛肉制品中帕斯雀牛肉、烤牛肉和酱牛肉彩虹色斑点最明显,猪肉制品中西式火腿片和咸肉最明显。     

水浴加热对牛半腱肌冷藏形成彩虹色斑的影响

研究水浴加热对牛半腱肌冷藏条件下形成彩虹色斑的影响。以新鲜牛半腱肌为实验材料,对其进行水浴(97℃)加热处理,使中心温度分别为70、80、90℃,在4℃条件下冷藏0～5 d,研究彩虹色斑强度、非血红素铁含量、蛋白质与脂质氧化、色泽等相关指标的变化,探讨水浴加热对牛半腱肌冷藏形成彩虹色斑的影响。结果表明,随水浴加热温度的升高和冷藏时间的延长,牛半腱肌彩虹色斑强度不断增强,其中亮度值(L*)和黄度值(b*)总体略有升高,而红度值(a*)略有降低,均出现显著差异(P<0.05);冷藏期间,牛半腱肌的非血红素铁含量、硫代巴比妥酸反应物(thiobarbituric acid reactive substance,TBARs)值、羰基含量显著升高(P<0.05),游离巯基含量显著降低(P<0.05);通过相关性分析得知,牛半腱肌彩虹色斑强度与非血红素铁含量、羰基含量、TBARs值呈显著正相关(P<0.05),与游离巯基含量呈显著负相关(P<0.05),与a*呈极显著负相关(P<0.01),可能是由于较高的非血红素铁含量促进TBARs值在冷藏0～1 d时迅速上升,同时促进蛋白质氧化进程,蛋白质与脂肪氧化过程同时发生,相互促进,从而共同影响彩虹色斑的形成。     

滚揉时间和添加赖氨酸对低盐蒸煮火腿品质的影响

研究不同滚揉时间和添加0.8%赖氨酸对于低盐蒸煮火腿保水性、质构特性和色泽等食用品质的影响。结果表明：随着滚揉时间的延长,火腿的蒸煮损失率逐渐降低,而赖氨酸的添加可进一步提高火腿的保水性,低场核磁共振结果显示这可能是由于火腿中不易流动水相对含量的增加;延长滚揉时间或添加赖氨酸对火腿质构有一定的改善作用,滚揉时间的延长会造成火腿红度值下降,同时,长时间滚揉或添加赖氨酸会引起蛋白质中的α-螺旋向β-折叠转变以及总巯基含量增加,这间接表明延长滚揉时间和添加0.8%赖氨酸可能有利于蛋白凝胶的形成。因此,延长滚揉时间至40 min和添加0.8%赖氨酸可以开发低盐蒸煮火腿,改善其品质特性。     

滚揉对羊肉成熟过程中钙激活中性蛋白酶活性的影响

以小尾寒羊背最长肌为研究对象,研究轻度滚揉(滚揉10 min)和重度滚揉(滚揉30 min)2种滚揉处理对羊肉成熟过程中钙激活中性蛋白酶活性的影响。结果表明,宰后成熟12 h,滚揉处理显著提高了μ-calpain和calpastatin的活性(p0.05),随着成熟时间的延长,各处理组的μ-calpain和calpastatin活性显著下降(p0.05),且滚揉处理组下降速度快于不滚揉组;滚揉处理对m-calpain活性影响不显著(p0.05),其活性随着成熟时间延长也显著下降(p0.05)。     

白胡椒粉煮制过程中胡椒碱的溶出及变化规律研究

为研究白胡椒粉中胡椒碱在煮制过程中的溶出及变化规律,考察了常压煮制和高压煮制两种煮制方式以及料液比、粉碎粒度、煮制时间、食盐添加量等因素对水煮液及煮制残渣中胡椒碱含量的影响。结果表明,煮制方式对胡椒煮制液和煮制残渣中的胡椒碱含量影响较大,常压煮制液和残渣中胡椒碱含量均显著高于高压煮制的,高压煮制相对常压煮制更容易造成胡椒碱的损失;在两种煮制方式下,煮制液中的胡椒碱均随着料液比的增加呈缓慢降低趋势、随着粉碎粒度的增加呈缓慢增加趋势,煮制时间和食盐添加量对煮制液中胡椒碱的溶出影响较小,但不同煮制时间和食盐添加量下煮制残渣中胡椒碱的含量存在显著性差异,白胡椒粉碎粒度越细,煮制液中胡椒碱的溶出率相对越高。     

不同腌制工艺对发酵芹菜粉发色效果的研究

芹菜粉富含天然的硝酸盐,是新型肉制品发色剂之一。以腌肉色泽、挥发性盐基氮含量及亚硝酸盐含量为指标,研究不同腌制工艺(4 ℃静置腌制、常压滚揉腌制、真空滚揉腌制)对发酵芹菜粉发色效果的影响。结果表明:真空滚揉工艺发色效果最好,且最佳条件是在真空度0.06 MPa条件下,以5 r/min的滚揉转速滚揉6 h。添加发酵芹菜粉的猪肉在真空滚揉腌制下的a^*值(红度)显著高于其他组(P<0.05);亚硝酸盐含量显著低于其他组(P<0.05);挥发性盐基氮含量低于其他组,且与4 ℃静置腌制组有显著差异(P<0.05)。     

不同处理对新疆羊半腱肌嫩度的影响

目的:寻求一种成本低、安全健康、嫩化效果好的嫩化方法。方法:以剪切力、pH值、蒸煮损失、肌原纤维小片化指数(myofibrillar fraglllentation index,MFI)、胶原蛋白含量及其溶解度、羊半腱肌全骨架蛋白降解情况等为评价指标,研究腌制结合滚揉、真空滚揉及腌制结合真空滚揉对羊肉嫩度的影响。结果表明:3种处理对羊肉的剪切力、pH值、蒸煮损失、肌原纤维小片化指数均影响显著。结论:采用真空滚揉对羊肉嫩化效果最佳。     

马铃薯淀粉添加量对真空滚揉调理鸡柳品质的影响

目的 探讨马铃薯淀粉结合真空滚揉腌制技术对调理鸡柳品质特性的影响。方法 通过测定调理鸡柳的出品率、蒸煮损失、水分含量、水分活度、色差、质构特征和剪切力等指标,探究不同马铃薯淀粉添加量（0.5、1.0、1.5、2.0和2.5%,w/w）对真空滚揉腌制调理鸡柳品质特性的影响。结果 随着马铃薯淀粉添加量的增加,调理鸡柳的出品率、嫩度、弹性、回复性、凝聚性、亮度值和红度值显著提高（P < 0.05）。然而,调理鸡柳的水分含量、水分活度、蒸煮损失、硬度则随着淀粉添加量的增加而显著下降（P < 0.05）,黄度值没有显著变化（P > 0.05）。结论 马铃薯淀粉的添加对真空滚揉腌制的调理鸡柳品质特性具有良好的促进作用,且以2.0%为最佳添加量。本研究为更高品质的调理鸡柳的工业生产提供技术支撑。     

呼吸式滚揉工作时间对调理牛肉品质的影响

与传统真空滚揉相比,呼吸式滚揉具有处理时间短、腌制效率高等优点。本研究以牛肉为原料,探究呼吸式滚揉工作时间（滚揉10 min/暂停5 min、滚揉15 min/暂停5 min、滚揉20 min/暂停5 min、滚揉25 min/暂停5 min）对调理牛肉品质的影响。结果表明,随着滚揉工作时间的增加,腌制吸收率、水分含量和pH均呈现先上升后下降的趋势,而蒸煮损失、离心损失及剪切力则呈现先下降后上升趋势,均在滚揉20 min/暂停5 min时达到最佳。与此同时,滚揉20 min/暂停5 min组样品具有最高的a*值和持水能力。扫描电镜结果表明肌纤维降解程度随着滚揉工作时间增加而加大,与电泳结果相一致。因此,滚揉20 min/暂停5 min为最佳滚揉参数,显著提高了调理牛肉的出品率,并改善了产品的品质特性（P<0.05）,在肉品工业中具有良好的应用前景。     

响应面法优化真菌蛋白酶嫩化马肉的工艺

为了改善马肉（半腱肌）的嫩度,以蒸煮损失率、剪切力和感官评分为评价指标,结合滚揉处理,研究了真菌蛋白酶在不同的添加量、处理温度、处理时间和pH值对马肉嫩度的影响,并利用响应面优化出了真菌蛋白酶的最佳嫩化条件。结果表明：真菌蛋白酶的添加量对马肉的嫩度影响极显著,处理温度和处理时间影响显著;最佳的嫩化条件是：真菌蛋白酶添加量20.63 U/g,处理温度53.12 ℃,处理时间98.88 min,pH值为6.86。     

肉品中彩虹色斑产生机理及研究进展

具有完整肌肉结构的原料肉及肉制品表面经常会产生彩虹色斑，是由光线与肉的微观结构相互作用导致的，但彩虹色斑往往被消费者误认为是肉类不新鲜或被污染。本文针对肉中彩虹色斑的成因及影响因素，主要从肉中影响光散射的微观结构及其在贮藏加工中的变化、肉类彩虹色斑产生的两大主要理论（表面光栅和多层干涉）、彩虹色斑测定表征的方法，以及影响肉中彩虹色斑的理化因素及控制消除技术这四方面进行综述，对肉中彩虹色斑现象的发生、调控机制进行全面的梳理，旨在为肉品科学的研究及肉类的生产、消费提供理论参考。     

The effect of various types of poultry pre- and post-rigor meats on emulsification capacity, water-holding capacity and cooking loss

In this study, the relationship between various kinds of poultry meat (quail, partridge, chicken and turkey) on pH, emulsification capacity, water-holding capacity and cooking loss was investigated. The effect of rigor state on pH, emulsification capacity, water-holding capacity and cooking loss was also determined. To investigate these parameters, immediately after slaughter and deboning, meat parts were submitted to both pre- and post-rigor analyses. The results indicated that the emulsification capacity of quail and chicken meat was higher than the values for partridge and turkey meat. Quail meat showed the highest water-holding capacity value in the post-rigor stage. The lowest cooking loss value was found in partridge meat, in both pre- and post-rigor stages. The state of rigor had a significant (P<0.05; P0.01) effect on pH and cooking loss values, respectively.     

Optical Characteristics of Natural Iridescence in Meat

Optical characteristics of microstructural iridescence in cooked cured beef were studied by transmission and reflectance light microscopy and by fiber optic spectrophotometry. Green iridescence was the most common color in individual muscle fibers. It had a peak spectral emission at 560 nm that was absent from the spectrum of bright green degraded heme pigment. Orange-red iridescence was the next most common color, with a major peak at 650 nm and a secondary peak at 460 nm. When examined microscopically, greenness due to microstructural iridescence disappeared from individual muscle fibers when 1 mm transverse sections of meat were illuminated with transmitted light. In the same sections, iridescent greenness produced by oblique illumination at 45° above the sample surface disappeared at some point when the sample was rotated about its axis.     

Factors Relating to Oxidative Stability of Cooked Broiler Breast Patties Treated with Sodium Tripolyphosphate

Broiler breast meat patties were prepared with 0, 0.2, and 0.5% sodium tripolyphosphate (STPP) at 3 pH values and 3 ionic strengths (IOS). The concentrations of STPP and IOS were important factors in retardation of oxidation during cooking and storage after cooking as evaluated by the thiobarbituric acid-reactive substances (TBA-RS) test. The effect of STPP at 0.5% was enhanced (P< 0.06) by raising its pH to 7.5 or 9. Increasing IOS by 0.6 raised TBA-RS values in raw meat and during cooking, but it had a reverse effect on cooked-stored patties, which was probably due to the lower nonheme iron content of cooked patties as the IOS increased.     

烹制时间对狮子头营养品质和挥发性风味物质的影响

为探究烹制时间对狮子头营养品质和挥发性风味物质的影响,该文对不同烹制时间条件下狮子头的基础营养成分、色泽、卡路里、质构、嫩度和挥发性风味物质指标进行研究。结果表明,不同烹制时间对狮子头的营养品质和挥发性风味物质含量影响显著(P<0.05)。烹制过程使狮子头中水分含量增加显著(P<0.05)。与原料肉相比,烹至120 min时狮子头比原料肉中的脂肪含量降低了17.97%;狮子头肥肉部位L值随着烹制时间的延长,呈先降低再升高的趋势,而瘦肉部位的L值则呈现先升高再降低趋势。烹制过程使狮子头的卡路里热量降低了41.04%。经质构分析,在烹制过程中狮子头的硬度、咀嚼性、嫩度值变化显著(P<0.05),烹至120 min时,狮子头达到口感嫩滑、入口即化的口腔状态。通过固相微萃取-气相色谱质谱联用技术从狮子头中共分离鉴定出76种挥发性风味物质,主要包括醛类、酯类、脂肪烃类、醇类、酸类以及其他类风味化合物。     

Concentration of Umami Compounds in Pork Meat and Cooking Juice with Different Cooking Times and Temperatures

This study examined the concentrations of umami compounds in pork loins cooked at 3 different temperatures and 3 different lengths of cooking times. The pork loins were cooked with the sous vide technique. The free amino acids (FAAs), glutamic acid and aspartic acid; the 5′‐nucleotides, inosine‐5′‐monophosphate (IMP) and adenosine‐5′‐monophosphate (AMP); and corresponding nucleoside inosine of the cooked meat and its released juice were determined by high‐performance liquid chromatography. Under the experimental conditions used, the cooking temperature played a more important role than the cooking time in the concentration of the analyzed compounds. The amino acid concentrations in the meat did not remain constant under these experimental conditions. The most notable effect observed was that of the cooking temperature and the higher amino acid concentrations in the released juice of meat cooked at 80 °C compared with 60 and 70 °C. This is most likely due to the heat induced hydrolysis of proteins and peptides releasing water soluble FAAs from the meat into the cooking juice. In this experiment, the cooking time and temperature had no influence on the IMP concentrations observed. However, the AMP concentrations increased with the increasing temperature and time. This suggests that the choice of time and temperature in sous vide cooking affects the nucleotide concentration of pork meat. The Sous vide technique proved to be a good technique to preserve the cooking juice and the results presented here show that cooking juice is rich in umami compounds, which can be used to provide a savory or brothy taste.     

空气解冻温度对猪里脊肉品质的影响

以冷冻猪里脊肉为研究对象,在4、12、20、30 ℃温度条件下对其进行空气解冻,测定猪里脊肉解冻时 间、汁液流失率、蒸煮损失率、保水性、pH值、色泽、水分分布、质构和微观结构等特性变化。结果表明：猪里 脊肉汁液流失率与解冻时间呈非线性关系;12、20 ℃空气解冻对猪里脊肉的保水性影响较小;不同空气解冻温 度对猪里脊肉pH值、亮度值和红度值无显著影响;30 ℃空气解冻对猪里脊肉中不易流动水影响最小,稳定性 最好,其次为20、4、12 ℃;与对照组鲜肉相比,不同温度空气解冻处理组猪里脊肉蒸煮后硬度存在显著差异 （P＜0.05）;12 ℃空气解冻后猪里脊肉中肌纤维间空隙变大。不同空气解冻温度对猪里脊肉品质的影响存在 差异性。     

Effect of electron-beam irradiation before and after cooking on the chemical properties of beef, pork, and chicken

Ground beef, pork, and chicken thigh meats were irradiated at 0 or 5.0kGy before and after cooking and then stored at -40°C in oxygen permeable bags. The pH, lipid oxidation, volatiles, and carbon monoxide production of the meat were determined at 0 and 6months of storage. The pH values of raw meats from different animal species were different (5.36-6.25) and were significantly increased by cooking, irradiation, and storage (p<0.05). Irradiation had no effect on the TBARS values of ground beef and pork, but significantly increased the TBARS of chicken thigh meat. Cooking, whether it was done before or after irradiation, caused significant increase in TBARS and was most significant in chicken and pork. The numbers of volatiles analyzed by GC/MS were higher in irradiated meats than the non-irradiated ones regardless of meat source. Sulfur-containing compounds were newly produced or increased by irradiation, but dimethyl disulfide and dimethyl trisulfide were not detected in the non-irradiated meats regardless of cooking treatment. Irradiation time, whether done before or after cooking, had little effect on the TBARS, volatiles, and carbon monoxide production in the meat.     

Effect of freezing temperature, thawing and cooking rate on water distribution in two pork qualities

The effects of freezing temperature (-20 versus -80°C) in combination with long-term freezer storage (-20°C) on water mobility and distribution in pork of two qualities (normal and high ultimate pH) were explored using low-field NMR T(2) relaxometry. A marked effect of freezing temperature on the characteristics of intra- and extramyofibrillar water (T(2) relaxation times) in the thawed pork was demonstrated, implying that the freezing temperature in combination with prolonged freezer storage affects the distribution and chemical-physical state of water in the thawed meat. Determination of technological properties (thawing and cooking loss) revealed that the observed T(2) variations related to water distribution and water properties, which were found to be consistent with the degree of structural damage assessed by light microscopy, also were reflected in the technological quality of the meat. Low freezing temperature in combination with prolonged freezer storage was associated with increased thawing and cooking loss. In addition, pH in the fresh meat had a pronounced effect on the distribution of myofibrillar water, as a more homogenous pore size distribution was evident in meat with high pH compared with normal pH. A clear effect of cooking rate on the T(2) relaxation characteristics in the cooked pork was also demonstrated, probably reflecting a cooking rate-induced effect on the myofibrillar structures. The effect of cooking rate on water distribution resulted in a significantly lower cooking loss upon a slow cooking rate (0.5°C/min from 25 to 65°C and 0.3°C/min from 65 to 80°C) compared with a fast cooking rate (1°C/min).