热风干过程中风干肉水分的迁移

Study of the Moisture Migration of Dried Meat During Hot Air Drying

为阐明热风干过程中风干肉水分迁移机制,利用氢质子低场核磁共振弛豫研究热风干过程中(温度35℃、湿度60%、风速3 m·s-1)风干肉内部和外部中水分迁移及水-蛋白相互作用模式。结果表明,在风干过程中风干肉中水分的主要存在形式为不易流动水,其不断从肌原纤维网络内迁移到网络外,水分含量显著下降。风干肉外部中结合水、不易流动水和自由水的弛豫时间均显著下降(P <0. 05),表明风干肉外部中水-蛋白相互作用模式发生改变。而风干肉内部中结合水和自由水的弛豫时间无显著变化(P> 0. 05),表明风干过程中风干肉内部和外部中水-蛋白相互作用不同,风干肉表皮的温度较内部温度高,且表皮水分含量下降速度较内部的水分含量下降速度快,导致了硬壳的形成。综上所述,风干过程中风干肉外部的温度高且水分脱除快,导致了风干肉内外部中水-蛋白相互作用不同。本研究结果为调控风干过程中水分迁移速度,实现风干肉工业化加工提供了理论依据。

For elucidating the mechanism of moisture migration in the process of hot air drying of dried meat,this study used low-field nuclear magnetic resonance to investigate the moisture migration and protein-water interaction of dried meat during hot air drying under lower temperature(temperature:35℃,relative humidity:60%,wind speed:3 m/s).It is found the immobilized water(intra-myofibrillar)was the main form of water in dried meat.During air drying,the immobilized water migrated to the extra-myofibril,and the content was decreased.The relaxation times of all water populations including free water,immobilized water,and bound water of external part of dried meat decreased with drying,indicating that the water-protein interactions changed(P<0.05).However,in the inner part of the dried meat,the relaxation times of free water and bound water did not decrease,implying that the water-protein interaction in inner part was different with the one in the external part of dried meat.This might be due to the higher temperature and lower water content in the external part of the dried meat.In conclusion,the faster water migration and higher temperature in the external part of dried meat caused the differences of water-protein interaction between inner and external part of dried meat.In conclusion,the faster water migration and higher temperature in the external part of dried meat caused the differences of water-protein interaction between the inner and external part of dried meat.