牛肉加热过程中水分迁移规律研究

采用100℃隔水加热方式加热牛肉28 min,每隔7 min采集一次样品,利用LF-NMR技术初步探讨牛肉加热过程中水分迁移规律。结果表明:随着加热时间的延长,牛肉蒸煮损失呈现上升趋势,剪切力不断增大,核磁数据显示牛肉内部水分状态组成变化显著,T2弛豫时间逐渐变短,不易流动水T22占比逐渐减少,自由水T23占比逐渐增多,且随着加热时间的延长,不易流动水和自由水很难在T2弛豫谱上分开,峰宽变大趋势明显,核磁成像结果显示加热会降低牛肉内部的水分含量。相关性分析结果表明:T21与牛肉的蒸煮损失呈显著正相关,T22与牛肉的蒸煮损失、剪切力呈显著负相关,T22峰面积占比与T2b、牛肉的蒸煮损失、剪切力呈显著负相关。由此得出加热处理对牛肉内部的水分分布和质构特性产生显著影响,同时两者之间存在相关性。

Study on Water Migration Law in Beef during Heating

Beef packaged in waterproof bags was cooked in a water bath at 100℃for 28 min,and beef samples were collected every 7 minutes,dynamic changes of water distribution in beef during heating process was investigated by LF-NMR.The results showed that with the prolongation of heating time,both cooking loss and shear force increased during heating.The NMR data showed that the composition of moisture in beef changed significantly.T2 relaxation time shortened gradually,the proportion of less mobile water T22 decreased gradually and the proportion of free water T23 increased gradually,it was difficult to separate T2 and T3 on T2 relaxation spectrum,and the peak width increased obviously.MRI images showed that the water content of beef reduced in heating process.The correlation analysis showed there was a significant positive correlation between cooking loss and T21,T22 and cooking loss,shearing force showed a significant negative correlation,T22 peak ratio and T2b,cooking loss,shearing force showed a significant negative correlation.Our study suggested that the water distribution and texture characteristics of beef were significantly affected by heating treatment,and there was a correlation between them.