摘要
牛肉宰后初始阶段的生理生化指标变化,会对宰后成熟期间牦牛肉嫩度品质的形成产生影响,该研究有助于牦牛肉成熟及嫩度改善理论的完善。为了明确宰后生理生化指标的变化对牦牛肉嫩度形成的影响,该研究选取18头公牦牛,宰后取背最长肌,在4℃条件下储藏成熟,测定pH值、糖原含量、依钙蛋白酶活力(calpain activity,CA)、肌原纤维小片化指数(myofibrillar fragmentation index,MFI)、肌节长度、肌纤维直径和剪切力,并通过动力学分析确定部分指标的变化幅度和速度参数。然后采用"刀切法",筛选出4个变量作为预测因子:依钙蛋白酶活力下降速率(RCA)、pH值下降幅度(EpH)、pH值下降速率(RpH)、糖原下降速率(RGlu),并通过线性回归构建宰后6d剪切力的预测模型,所得预测方程拟合度R2=0.703。经过验证,预测方程可给出与真实值相差极小的预测值。通过预测模型,可以根据牦牛宰后3d内生理生化指标的变化,对宰后6d牦牛肉的剪切力实现有效预测。
Tenderness is one of important sensorial properties for the quantitative evaluation of eating qualities influencing the consumption of beef, and the others are juiciness and flavor respectively. Poor tenderness is one of main causes for commercial unacceptability of yak meat. The variation of physiological and biochemical characteristics during tenderization at the initial phase of postmortem aging has an extraordinarily significant effect on the postmortem formation of the tenderness property of beef cuts, which is one of determinant factors for consumers to decide if the beef products should be purchased. Therefore, the improvement of research on the effect of physiological and biochemical characteristics on the tenderness of yak meat is beneficial to melioration of the theory of postmortem aging and tenderization of yak meat. In order to investigate the effect of the postmortem variation of physiological and biochemical characteristics on the formation of tenderness of yak meat, pH, glycogen content, calpain activity （CA）, the myofibrillar fragmentation index （MFI）, sarcomere length, myofiber diameter, and shearing force of M. longissimus dorsi stored at 4℃ for 10d from 18 male yaks were determined. The estimated value of 6 characteristics at postmortem 1 h were obtained directly as alternative predictors of a predictive model of postmortem tenderness of yak meat. Meanwhile, the kinetic parameters of the rate and extent of variation of some physiological and biochemical characteristics including pH, CA, MFI and glycogen content obtained by kinetic data analysis within postmortem 72 h were also selected as alternative predictors. The ultimate predictors of a predictive model of postmortem tenderness of yak meat were determined through a ＂jackknife＂ method from all alternative predictors, including 6 variables at postmortem 1 h and 7 kinetic parameters within postmortem 72 h according to occurrences in optimal equations of 15 jackknife samples through multiple linear step regression analysis. The ultimate predictors included rate of CA decline （R CA ）, extent of pH decline （E pH ）, rate of pH decline （R pH ）, and rate of glucogen decline （R Glu ）. The predictive model of tenderness was also built within a randomly selected 15 male yaks different from the jackknife samples through multiple linear enter regression analysis, to shearing force at postmortem 6 d （T 6 ） as the dependent variables, to the above four predictors as independent variables. The predictive equation is T 6 = 50.414 ＋ 10.924E pH ＋ 53.029R pH - 519.690R CA ＋ 65.757R Glu , with determinate coefficient R 2 of 0.703, which could explain 70.3% of the variability of the shearing force of yak meat at postmortem 6d. The data of the other 3 male yaks was used as a validation set. The determinate coefficient R 2 between the predictive value obtained by model and reference value of the validation set was 0.977. The relative errors between predictive value and reference value of the validation set were not higher than 5%. Therefore, the tenderness of yak meat at postmortem 6d could be effectively predicted through this predictive model, based on the variation of physiological and biochemical characteristics within postmortem 72h.
出处
《农业工程学报》
EI
CAS
CSCD
北大核心
2013年第16期286-292,共7页
Transactions of the Chinese Society of Agricultural Engineering
基金
公益性行业(农业)科研专项资助(201203009)
国家现代农业(肉牛牦牛)产业技术体系资助项目(CARS-38)
甘肃省青年科技基金项目(1107RJYA064)
关键词
肉
生理
生化
嫩度
预测模型
宰后成熟
meat
physiology
biochemistry
tenderness
predictive model
aging
