CAJ | 학술논문

为了研究宰后成熟时间对牦牛肉品质的影响，该研究采集牦牛背最长肌，真空包装后进行成熟排酸，成熟期间取样测定pH值、剪切力、持水能力、色度，并通过标准化和动力学模型分析研究其变化规律。结果发现，除了黄色度b*以外，其余品质指标均在21d的成熟过程中有显著变化（P<0.05）。相比于7 d成熟，延长至21 d的长时间成熟可将牦牛肉剪切力显著地降低47%（P<0.05），并将蒸煮损失和红色度a*分别显著地提高28%和32%（P<0.05）。通过对比线性函数、指数函数、二次函数对牦牛肉品质变化的预测效果，结果发现二次函数预测模型与牦牛肉宰后品质变化具有相对最好的拟合度（决定系数R2范围为0.90～0.98），其中pH值、剪切力、加压损失、亮度L*值随时间的变化函数呈现出凸函数特征，而蒸煮损失和a*值则呈现出凹函数特征。结果表明，相比于牛肉品质宰后预测中常用的线性函数和指数函数而言，二次函数更适用于牦牛肉品质变化的预测，而将牦牛肉宰后成熟时间延长至21 d可有效降低牦牛肉剪切力。研究可为牦牛肉品质控制提供参考。
위료연구재후성숙시간대모우육품질적영향，해연구채집모우배최장기，진공포장후진행성숙배산，성숙기간취양측정pH치、전절력、지수능력、색도，병통과표준화화동역학모형분석연구기변화규률。결과발현，제료황색도b*이외，기여품질지표균재21d적성숙과정중유현저변화（P<0.05）。상비우7 d성숙，연장지21 d적장시간성숙가장모우육전절력현저지강저47%（P<0.05），병장증자손실화홍색도a*분별현저지제고28%화32%（P<0.05）。통과대비선성함수、지수함수、이차함수대모우육품질변화적예측효과，결과발현이차함수예측모형여모우육재후품질변화구유상대최호적의합도（결정계수R2범위위0.90～0.98），기중pH치、전절력、가압손실、량도L*치수시간적변화함수정현출철함수특정，이증자손실화a*치칙정현출요함수특정。결과표명，상비우우육품질재후예측중상용적선성함수화지수함수이언，이차함수경괄용우모우육품질변화적예측，이장모우육재후성숙시간연장지21 d가유효강저모우육전절력。연구가위모우육품질공제제공삼고。
There are more than 16 million yaks in China, which accounting for about 95%of total amount in the world. The yak beef could be a new resource for meat industry in China with high protein, low fat and unique flavour. However, the commercial potential of yak beef is limited because of the poor tenderness of yak beef. The aging could be a simple and effective method to improve tenderness of beef especially prolonged aging time more than 14 d. In order to investigate the prolonged aging time on quality traits of yak meat, the pH value, tenderness (WBSF, Warner Bratzler shear force), water holding capacity (WHC, including cooking loss and press loss) and chroma (L*, a* and b*) of M. longissimus dorsi removed from yak within postmortem 2 h were determined during 21 d aging after vacuum packaging, and the changing patterns of quality traits of yak beef were analyzed through standardization of variables and kinetic model. It was found that there were significant variations during 21 d aging for quality traits (P<0.05) except b*value. The main variation of pH values during postmortem aging occurred in 3 d of early postmortem, while yak beef aging for 21 d did not have a lower pH value than those aging for 7 d. The aging of 7 d decreased the WBSF by 43 N, but the average WBSF of yak beef aging for 7 d still higher than 50 N. The WBSF of yak beef aging for 21 d was lower to 30 N, which was 47%significantly lower than that aging for 7 d (P<0.05). The cooking loss of yak beef significantly increased from 40.4%to 51.5%when aging time was prolonged from 7 d to 21 d (P<0.05), while the prolonged aging of 21 d did not have a significant effect on press loss of yak beef (P>0.05). The L*value significantly decreased with aging time during early aging of 7 d (P<0.05), but there was no significant difference on L* value between yak beef aging for 21 d and 7 d (P>0.05). However, a* value (redness) of yak beef significantly increased with prolonged aging time, and a*value of yak beef aging for 21 d was 32% higher compared to that aging for 7 d (P<0.05). Meanwhile, the changing pattern of quality traits of yak beef with significant change during aging was also investigated through standardization of variables and kinetic model analysis. It was found that the quadratic function had best predicting performance on quality traits of yak meat with coefficients of determination R2 ranged from 0.90 to 0.98, through comparing fitting degree of linear, exponential and quadratic functions. The changes of pH value, shearing force, press loss and L* were characterized by the convex function with negative second derivative, while cooking loss and a*value were characterized by the concave function with positive second derivative. It shows that the prolonged aging can be beneficial to improvement of tenderness, but has adverse effects on water holding capacity and meat color. Conclusively, different quality traits have different changing patterns and vary on different phases of aging.