低场核磁共振测定鲜猪肉中水分分布的制样方法

Sampling method for low field nuclear magnetic resonance measurement of moisture distribution in pork

中文关键词:  猪肉  制样  水分分布  低场核磁共振

英文关键词:pork  sample preparation  moisture distribution  low field nuclear magnetic resonance

中文摘要:

      目的 应用低场核磁共振技术(low field nuclear magnetic resonance, LF-NMR)测定不同鲜猪肉的制样方法(肉样大小、分切方向、是否包膜)的水分分布, 以确定其较佳制样方法。方法 以宰后24 h的猪背最长肌为对象, 采用单因素实验, 分别按不同大小、不同分切方向和包膜与否进行3组实验, 对LF-NMR的弛豫时间T2相关指标进行方差分析和多重比较。结果 随着肉样质量的增加, T2b先减小后增大(P<0.05), A2b、A21逐渐增加(P<0.05); 肉样分切方向不影响样品水分含量分布测定结果; 而包膜使样品的T2b减小、A2b和P2b增加(P<0.05)。结论 猪肉的制样样品大小为2.0 cm(长)×1.0 cm(宽)×1.0 cm(高), 分切方向为沿肌肉方向, 不包膜处理, 这种制样方法对样品中水分分布情况的影响最小, 能相对准确地反映实际样品中水分分布及含量。

英文摘要:

      Objective To study moisture distribution in fresh meat with different sample preparation methods (sample size, cutting direction, coverage with plastic membrane) by low field nuclear magnetic resonance (LF-NMR) technique. Methods Pork longissimus muscle was obtained at 24 h post-slaughter and then cut into different sizes to different directions, and the cubes were covered by plastic membrane or not. LF-NMR relaxation time T2 was measured and the observations were analyzed by analysis of variance and multiple comparison. Results The results showed that T2b decreased and then increased with increasing cube mass (P<0.05), and A2b and A21 gradually increased (P<0.05). Cutting direction did not affect moisture distribution. When the pork was packaged with plastic membrane, T2b decreased, but A2b and P2b increased (P<0.05). Conclusion Therefore, it is suggested of sample size of 2.0 cm (length)×1.0 cm (width)×1.0 cm (height), cutting along muscle direction and without coverage with plastic membrane. In this method, it has less effect on moisture distribution and can accurately reflect actual moisture distribution and level.