不同部位牦牛肉宰后成熟过程中肉色稳定性研究

为探究不同部位牦牛肉宰后成熟过程中肉色变化及肉色指标之间相互关系,该试验以川西北麦洼牦牛背阔肌、背最长肌和半腱肌3个部位肉为研究对象,置于4℃自然成熟并在相应时间点测定分析肌肉色泽、肉色稳定性指标总肌红蛋白(total myoglobin, TMb)含量、氧合肌红蛋白(oxymyoglobin, OMb)相对含量、高铁肌红蛋白(metmyoglobin, MMb)相对含量、高铁肌红蛋白还原酶(metmyoglobin reductase, MetMbR)活性及pH值。结果表明,随着成熟时间的延长,3个部位肉L^*值和a^*值呈先上升后下降趋势,背最长肌和半腱肌b^*值和H^*值均呈逐渐上升变化,背阔肌b^*值、H^*值呈先上升后下降趋势;TMb含量、OMb相对含量及MetMbR活性呈下降趋势,MMb相对含量显著升高(P<0.05);pH值呈先下降后保持相对稳定变化的趋势;相同时间点下,三者的L^*值和b^*值总体上无明显差...     

干腌火腿肌肉红色色素的形成机理条件和性质

腌制剂中添加硝酸盐或亚硝酸干腌火腿的特征性红色是由亚硝基肌红蛋白形成的。亚硝基肌红蛋白是由肌红蛋白与亚硝酸盐产生的一氧化氮发生反应而生成的。腌制荆中不添加硝酸盐或亚硝酸盐的干腌火腿的亮红色是锌-原卟啉Ⅸ形成的。这两种红色色素具有不同的性质。在整个加工过程中，腌制剂中不添加硝酸盐或亚硝酸盐的干腌火腿中锌-原卟啉Ⅸ的含量持续上升。腌制剂中添加亚硝酸盐会抑制锌-原卟啉Ⅸ的形成。     

异抗坏血酸钠、茶多酚、迷迭香酸和鼠尾草酸对冷鲜肉肉色稳定性的影响

牛肉在冷藏过程中,肌红蛋白容易被氧化为高铁肌红蛋白,使肉色变暗。主要研究异抗坏血酸钠、茶多酚、迷迭香酸和鼠尾草酸对冷鲜肉肉色稳定性的影响,以冷鲜肉为试材,选择异抗坏血酸钠、茶多酚、迷迭香酸(RAP)和鼠尾草酸(CAP)进行单因素试验,分析冷鲜肉在贮藏的第1、3、5、7、9天肉色(CIE系统,L*、a*和b*)变化,氧合肌红蛋白(OMb)、高铁肌红蛋白(MMb)相对含量。在单因素试验的基础上进行4因素3水平的正交试验,确定复合抗氧化剂异抗坏血酸钠、茶多酚、RAP、CAP的最佳配比。随着冷藏时间的延长,肉样的L*和a*不断降低,b*呈升高趋势,同时添加异抗坏酸钠、茶多酚、RAP、CAP和对照组冷藏牛肉中OMb%变化呈下降趋势,MMb%呈上升趋势,通过OMb、MMb与L*、a*和b*相关性分析,可以得出OMb和MMb的相对含量与牛肉的L*、a*和b*呈显著相关性(p0.05);添加异抗坏血酸钠、茶多酚、RAP、CAP和对照组冷藏牛肉在1 d~5 d内OMb%和MMb%变化显著(p0.05);添加异抗坏血酸钠、茶多酚、RAP和CAP浓度的增大,肉样中MMb%越小,对MMb的抑制作用越大,茶多酚添加量为0.02%的抑制效果最好;通过正交试验确定异抗坏血酸钠、茶多酚、RAP和CAP最佳配比为0.012%、0.02%、0.016%、0.02%。结果说明,异抗坏血酸钠、茶多酚、RAP和CAP可以降低肌红蛋白氧化程度,提高肉色稳定性,这为更全面地评价牛肉品质提供科学依据,也为日后研究抗氧化剂对肉色稳定性的影响提供了理论依据。     

苏尼特羊不同部位肌肉抗氧化系统的差异

以放牧条件下的苏尼特羊股二头肌、臂三头肌和背最长肌3个部位的肌肉为材料,测定其丙二醛(MDA)、氧合肌红蛋白(OMb)、高铁肌红蛋白(MMb)含量、抗氧化酶活性(超氧化物歧化酶SOD、过氧化氢酶CAT、谷胱甘肽过氧化物酶GSH-Px)、抗氧化能力(降铜离子还原能力CUPRAC、自由基清除率RSA)、色差和pH值等指标,比较不同部位之间的差异。结果表明:抗氧化酶和抗氧化性能中,臂三头肌的SOD与GSH-Px活性最高,而背最长肌中的CAT活性、CUPRAC和RSA最高。背最长肌的pH值最高,而MDA、L*值、a*值和b*值均显著低于股二头肌和臂三头肌(P<0.05)。股二头肌中OMb显著高于臂三头肌和背最长肌(P<0.05),而MMb显著低于其它部位(P<0.05)。苏尼特羊肌肉中的抗氧化酶之间具有协同作用,且抗氧化酶活力的增强能提高机体抗氧化性能,降低氧化程度。整体上,苏尼特羊背最长肌中抗氧化物质含量较高,脂质氧化程度低于其它两个部位,抗氧化能力较强。     

迷迭香结合气调包装对牛肉肉色稳定性的影响

生鲜肉在冷藏过程中肌红蛋白会发生氧化导致肉色变暗,迷迭香酸提取物和一氧化碳气调包装(CO-MAP)均可降低肌红蛋白氧化程度,使牛肉保持良好的色泽。研究主要探讨迷迭香提取物结合CO-MAP对冷鲜牛肉肉色稳定性的影响,利用动力学方程筛选迷迭香提取物的最佳添加浓度。结果发现,CO-MAP可显著抑制冷鲜牛肉储藏过程中OMb和MMb的生成,0.4%CO+30%CO_2+69.6%N_2对MMb抑制效果好。添加迷迭香提取物能更好稳定肉色,其中0.015%CAP20对MMb的抑制最为显著(p0.05),a~*显著提高,b~*显著降低(p0.05)。研究表明,迷迭香提取物结合CO-MAP可降低肌红蛋白氧化程度,使牛肉保持良好的色泽,这为日后研究天然抗氧化剂对肉色稳定性的影响提供了理论依据。     

蒙顶黄芽不同加工工序中色泽变化与品质相关性研究

研究不同加工工序制成的蒙顶黄芽干茶、汤色及叶底色泽,并进行色素成分检测及品质审评,分析干茶、汤色及叶底色泽L*a*b*值与各审评因子得分、色素含量、品质总分的相关性,为黄茶闷黄程度及色泽的评价提供一定的参考依据。以蒙顶黄芽加工过程中的茶样为试验材料,采用色彩色差计CR410测定干茶、汤色及叶底的L*a*b*值,再与干茶、汤色、叶底得分做显著性分析,与茶色素、叶绿素及品质总分做相关性分析。结果表明,干茶L*、a*、b*值与干茶色泽审评得分呈显著或极显著相关（P<0.05, P<0.01）,茶汤L*、a*、b*值与汤色审评得分均呈极显著相关（P<0.01）,其相关系数分别为?0.93、0.97、0.93,叶底L*、a*、b*值与叶底得分均呈极显著相关（P<0.01）,其相关系数分别为?0.96、0.97、0.98;干茶、汤色及叶底的L值与茶色素含量呈极显著负相关（P<0.01）,a*、b*值与茶色素含量呈极显著正相关（P<0.01）;干茶、汤色及叶底的L*值与叶绿素含量呈极显著正相关（P<0.01）,a*、b*值与叶绿素含量呈极显著负相关（P<0.01）。蒙顶黄芽感官品质与L*、a*、b*值及色素之间的相关性表现为:与干茶 L *值、汤色L *值、叶底L *值、叶绿素a*、叶绿素b*含量均呈极显著负相关（P<0.01）,与干茶a*b*值、汤色a*b*值、叶底 a*b*值及茶色素含量均呈显著或极显著正相关（P<0.05, P<0.01）,除干茶a*值外,相关系数均在0.80以上。本试验表明,就各审评因子及品质总分而言,采用色泽Lab值测定方法可为黄茶色泽与品质相关性研究提供一定的理论基础。     

蓝鳍金枪鱼脂肪氧化和鱼肉色泽的变化研究

结合脂肪氧化和鱼肉色泽指标,观察蓝鳍金枪鱼赤身肉、中腹肉和大腹肉在低温冻藏条件(-18℃)下的变化情况,并对各指标进行相关性分析。结果显示:随着冻藏时间的延长,3个部位肌肉的TBA值和metMb%(高铁肌红蛋白含量)增加;a*值、总色素含量和感官评定值都呈下降趋势;大腹肉变色最快,中腹肉次之,赤身肉最不明显;metMb%与a*值呈极显著负相关(R=-0.943,P0.01),与TBA值呈极显著正相关(R=0.914,P0.01)。分析认为蓝鳍金枪鱼各部位肌肉虽都有褐变的趋势,但速率不同,脂肪含量越高的部位褐变越快;若要保证金枪鱼鱼肉的色泽,必须采取措施防止脂肪氧化和高铁肌红蛋白的产生。     

宰后贮藏期间氧化磷酸化对秦川牛肉色泽的影响

为揭示宰后贮藏过程中牛肉肉色变化机制,以25月龄秦川牛背最长肌为研究对象,测定其贮藏0,4,8 d时pH值、肉色和肌红蛋白相对含量的变化情况。基于4D-非标记蛋白质组学技术研究贮藏期间氧化磷酸化代谢通路蛋白质表达量与肌红蛋白表达量之间的关系。结果表明:随着贮藏时间的延长,pH值呈先降低后升高的趋势。a*值逐渐降低,b*值逐渐升高,L*值呈先上升后下降的趋势。氧合肌红蛋白相对含量显著下降(P < 0.05),高铁肌红蛋白相对含量显著上升(P < 0.05),脱氧肌红蛋白相对含量变化不显著。肌红蛋白表达量在0~4 d 上调,4~8 d 下调。氧化磷酸化代谢通路上的关键蛋白质ATP5F1D贮藏初期上调,NDUFA4、NDUFB5贮藏后期下调,且氧化磷酸化代谢通路上的关键蛋白对牛背最长肌pH值、肉色均有显著影响。L*值与DeoMb相对含量呈极显著正相关(P < 0.01),与OxyMb相对含量呈极显著负相关(P < 0.01),与ATP5F1D呈极显著正相关(P < 0.01)。NDUFA5与高铁肌红蛋白相对含量呈显著负相关(P < 0.05)。因此,探究氧化磷酸化代谢通路关键蛋白质对肉色的影响,对于宰后肉品品质形成具有重要调控作用。     

秦川牛宰后肉色与其食用品质的相关性

为研究宰后牛肉肉色变化与其食用品质的相关性,以秦川牛背最长肌为研究对象,对宰后排酸成熟7d牛肉的肉色、肌红蛋白相对含量、pH值、剪切力、持水力及蒸煮损失率的变化进行分析,采用主成分分析和相关性分析相结合的方法研究肉色与其食用品质的相关性。结果表明：排酸过程中牛肉亮度值（L*）和红度值（a*）呈现先上升后下降的趋势,黄度值（b*）缓慢上升;氧合肌红蛋白（oxymyoglobin,OxyMb）相对含量持续下降;脱氧肌红蛋白（deoxymyoglobin,DeoxyMb）相对含量先上升,5d后缓慢下降;高铁肌红蛋白（metmyoglobin,MetMb）相对含量逐渐上升;pH值先降低,5d后回升;持水力和剪切力逐渐减小;蒸煮损失率先呈上升趋势,7d后下降;L*与DeoxyMb相对含量呈极显著正相关（P＜0.01）,OxyMb相对含量与MetMb相对含量呈极显著负相关（P＜0.01）,MetMb相对含量与剪切力呈显著负相关（P＜0.05）,持水力与剪切力呈显著正相关（P＜0.05）,OxyMb相对含量与持水力和剪切力呈显著正相关（P＜0.05）,MetMb相对含量与持水力呈极显著负相关（P＜0.01）。     

射频等离子体活性水处理对火腿发色的影响

探讨射频等离子体活性水（radio frequency plasma activated water,RF-PAW）处理对肌红蛋白颜色及火腿发色的影响,对比亚硝酸钠溶液与RF-PAW的发色效果以及这2 种发色剂用于火腿发色后亚硝酸盐的残留量。结果表明,等离子体处理6 min以内得到的PAW,不会对高铁肌红蛋白（metmyoglobin,metMb）的颜色产生显著影响,会使氧合肌红蛋白逐渐氧化成metMb,颜色由鲜红色变为红棕色;肉眼观察发现,采用RF-PAW、亚硝酸盐溶液（nitrite,NI）作为亚硝酸盐来源来腌制火腿,都能使新鲜猪肉发色,且RF-PAW腌制的火腿发色效果更好,RF-PAW中的活性物质并未对火腿发色造成不良影响;色差分析结果显示,PAW腌制出的火腿有更高的a*、C*值以及更低的b*值,色素含量测定显示,PAW处理的火腿具有更高的亚硝化肌红蛋白色素百分比（43.52%）,说明PAW腌制比NI腌制形成更多的亚硝化肌红蛋白色素,使火腿的红色更深;通过亚硝酸盐残留测定发现,NI腌制的火腿亚硝酸盐残留量为54.45 mg/kg,而PAW腌制的火腿亚硝酸盐残留量为52.79 mg/kg,均小于国标限量值70 mg/kg。该研究结果为肉品低温等离子体保鲜与腌制技术的工程化应用提供理论基础和科学指导。     

Color and Heat Denaturation of Myoglobin Forms in Ground Beef

To determine the effects of myoglobin forms on internal cooked color in ground beef, patties containing predominantly deoxy-(DMb), oxy-(OMb), or metmyoglobin (MMb) were cooked to 55, 65, or 75 °C. Only patties with DMb appeared red and undercooked at 55 °C, and their color became progressively more brown at 65 and 75 °C. Patties with OMb and MMb were brown at 55 °C and could be mistakenly perceived as being cooked enough to consume. Judging the doneness of ground beef using internal cooked color alone would be valid only if the pigment at time of cooking was predominantly DMb. In model studies, DMb had greater thermal stability than MMb especially at higher pH.     

New procedure for improving precision and accuracy of instrumental color measurements of beef

The surface layers of steaks from bovine M. semimembranosus were prepared to have deoxy- (DMb), oxy- (OMb) and metmyoglobin (MMb) states using either chemicals (CHEM) or oxygen partial pressure packaging (OPP). Ninety-six different meat surface areas were measured in reflectance mode (400-1100 nm) for each preparation method. Reflectance spectra were converted to absorbance (A) and then transformed by Kubelka-Munk transformation (K/S) and/or extended multiplicative scatter correction (EMSC). Transformed spectra of prepared pure states were used to make calibration models of MMb, DMb and OMb using either selected wavelengths (SW) or partial least square (PLS) regression. Finally, the predicted myoglobin states were normalized to ensure that no state was <0 or >1 and the sum of all states equal to 1. Multivariate calibrations (i.e. PLS) outperformed the univariate calibrations (i.e. SW). The OPP method of preparing pure states was clearly best for OMb while the CHEM method was best for preparing MMb on fresh meat surfaces. Both preparation methods needed improvement concerning DMb. The CHEM(K/S) SW and the OPP EMSC(A) PLS methods predicted MMb, DMb and OMb with root-mean-square errors of cross validation (RMSECV) equal to 0.08, 0.16 and 0.18 (range 0-1) and 0.04, 0.04 and 0.04 (range 0-1), respectively. This new reflectance protocol has potential for routine meat color measurements.     

两种放牧方式对绒山羊肉抗氧化系统的影响

以草场放牧、山地放牧两种方式下的绒山羊背最长肌为实验材料,测定背最长肌的色泽、肌红蛋白含量、 丙二醛含量、氧合肌红蛋白相对含量、高铁肌红蛋白相对含量、抗氧化酶活力和总抗氧化能力等指标并进行比较分 析。结果表明：草场放牧绒山羊肉的红度、过氧化氢酶活力、谷胱甘肽过氧化物酶活力和自由基清除率均显著高于 山地放牧（P＜0.05）;草场放牧绒山羊肉亮度、黄度、高铁肌红蛋白相对含量、丙二醛含量均显著低于山地放牧 （P＜0.05）,但两种放牧方式绒山羊肉的肌红蛋白含量、氧合肌红蛋白相对含量、超氧化物歧化酶活力和总抗氧 化能力没有显著差异（P＞0.05）。在草场放牧条件下,绒山羊能摄食大量绿色牧草,并且有适宜的运动量,增加 了抗氧化酶的活力和肉色稳定性,自由基的产生和清除达到了平衡,从而使其肉品的抗氧化能力高于山地放牧。     

Determination of the myoglobin states in ground beef using non-invasive reflectance spectrometry and multivariate regression analysis

Seventy-two samples of ground beef from M. semimembranosus of two 5 and two 1.5 year old animals were prepared. Two types of fat tissues from either beef or pork were added to the ground beef. The samples were prepared to contain predominantly deoxymyoglobin (DMb), oxymyoglobin (OMb) and metmyoglobin (MMb) states on surfaces using selected methods based on chemical treatment (for MMb) and oxygen pressure packaging to induce the two other states. Reflectance spectra were measured on ground beef after three storage times. Partial least regression analysis was used to make calibration models of the desired myoglobin states. Validated models using leave-one-sample out cross validation gave, after correction and normalization, prediction errors of about 5%. Long term storage of ground beef was unsuitable for preparing pure MMb states due to gradual reduction of the pigment to DMb, presumably by bacteria.     

Retail Display Lighting Type and Fresh Pork Color

The effects of lighting type on fresh pork color were studied by displaying chops under delux cool white (DCW), cool white, Surlyn® coated (CWSC), or warm white (WW) fluorescent or cool flood (CF) incandescent lights. Initial color desirability was assessed. Hunter colorimeter values and percentage myoglobin (Mb), oxymyoglobin (OMb) aand metmyoglobin (MMb) were determined over 5 days of display. Light types CF and DCW provided the most desirable color rendition. Chops displayed under CF lights became darker, had less percentage OMb and greater Mb, and likely had greater microbial growth than other chops due to an increase in chop temperature. It appears that CF and DCW lights provide the most desirable color and that precautions against temperature elevation are needed.     

Sorption isotherms of salted minced pork and of lean surface of dry-cured hams at the end of the resting period using KCl as substitute for NaCl

The effect of KCl on sorption isotherms was determined on salted minced meat (with 0%, 30% and 100% molar substitution of NaCl by KCl) at 5 °C and 25 °C and meat from a 3 mm thick slice from the surface of dry-cured hams (with 0% and 35% molar substitution of NaCl by KCl) held at 70–75%, 75–80% and 80–85% air relative humidity during the resting period.

The sorption isotherms were determined gravimetrically by exposing the meat samples to several atmospheres of known relative humidity controlled by different saturated salts according to the COST90 method. The sorption equipment consisted of a chamber containing 11 containers, covering the water activity (a_w) range from 0.112 to 0.946 at 25 °C. The hermetically closed sorption containers filled with KCl and minced meat samples were irradiated at 3 kGrey (gamma irradiation ⁶⁰Co). The water content at equilibrium was higher in minced meat with NaCl than in minced meat with KCl (100% molar substitution of NaCl by KCl) at 5 °C within the range of 0.4313 and 0.7565 a_w. However, when substitution was 30% in minced meat and 35% in hams the isotherms were similar to isotherm without substitution.     

AMPK活化调控的能量代谢对宰后牦牛肉肉色稳定性影响的研究

为探究牦牛肉在宰后成熟过程中单磷酸腺苷激活蛋白激酶（AMPK）活化调控的能量代谢对肉色稳定性的影响,本实验以牦牛背最长肌为研究对象,使用AMPK激活剂（AICAR）和抑制剂（Compound C）对其进行处理,并置于4 ℃下成熟,在相应的成熟时间点对AMPK活性、肉色及能量代谢相关指标进行测定,并进行肉色和能量代谢指标相关性分析。结果表明:成熟至12 h,与对照组相比,AICAR组AMPK活力提高了13.17%,而抑制组降低了9.03%,表明AICAR对AMPK活性有激活作用,而Compound C对AMPK活性有明显的抑制作用。随着成熟时间的延长,三者的L*值、a*值和己糖激酶的活性均呈先上升后下降趋势,b*值、H*值、乳酸含量均呈逐渐上升的趋势,其中L*值、b*值和H*值始终为AICAR组>对照组>Compound C组,a*值始终为AICAR组<对照组相似文献   

Spectral characterisation of red pigment in Italian-type dry-cured ham. Increasing lipophilicity during processing and maturation

Spectroscopic studies of Parma ham during processing revealed a gradual transformation of muscle myoglobin, initiated by salting and continuing during ageing. Electron spin resonance spectra did, however, conclusively show that the pigment in dry-cured Parma ham at no stage is a nitrosyl complex of ferrous myoglobin as found in brine-cured ham and Spanish Serrano hams. Both near-infra red reflectance spectra of sliced ham and UV/visible absorption spectra of extract of hams, obtained with aqueous buffer or acetone, showed the presence of different red pigments at varying processing stages for both solvents. Especially, the pigment extracted with aqueous buffer exhibited unique spectral features different from those of well-known myoglobin derivatives. At the end of processing, the pigment(s) becomes less water extractable, while the fraction of red pigment(s) extractable with acetone/water (75%/25%) increases throughout the processing time up to full maturation at 18 months. The chemical identity of the 6th ligand of myoglobin could not be conclusively established, but possible candidates are discussed. The partition of the pigment(s) between pentane and acetone/water showed a strong preference for pentane, suggesting that only the heme moiety is present in the acetone/water extract, and that Parma ham pigment is gradually transformed from a myoglobin derivative into a non-protein heme complex, which was found to be thermally stable in acetone/water solution