牛肉干中红外-热风组合干燥工艺中水分迁移规律  

Moisture mobility mechanism of beef jerky during combined mid-infrared and hot air drying

作　　者：谢小雷[1] 李侠[1] 张春晖[1] 王金枝[1] 王春青[1] 王兆进 穆国锋 

机构地区：[1]中国农业科学院农产品加工研究所农业部农产品加工综合性重点实验室,北京100193 [2]泰州圣泰科红外科技有限公司,泰州225300 [3]内蒙蒙都羊业食品有限公司,赤峰024000

出　　处：《农业工程学报》2014年第14期322-330,共9页Transactions of the Chinese Society of Agricultural Engineering

基　　金：公益性行业(农业)科研专项(201303082)

摘　　要：为研究牛肉干中红外-热风组合(combined mid-infrared and hot air,CMIHA)干燥过程中水分迁移的规律,进而阐明这种干燥工艺的合理性,在干燥温度70℃,辐射强度0.48 W/cm2,辐射距离8 cm,风速1 m/s的条件下,通过对比牛肉干CMIHA干燥和热风(hot air,HA)干燥的干燥曲线、热收缩率及测定水分扩散率、内外温差等指标,研究了牛肉干CMIHA干燥过程中水分迁移变化;借助水分低场核磁共振波谱(low field magnetic resonance spectroscopy,MRS)及氢质子成像(magnetic resonance imaging,MRI)技术分析牛肉干CMIHA干燥和HA干燥过程中水分的状态变化及分布,比较2种干燥方法对牛肉干内部3种状态水的横向弛豫时间、含量、信号幅度及H质子密度的影响,揭示CMIHA干燥牛肉干水分迁移规律。结果表明,与HA干燥相比,CMIHA干燥能够显著提高(p<0.05)干燥过程中牛肉干的内、外部温度及其温差,显著降低牛肉干收缩率(p<0.05),从而提高CMIHA干燥的水分扩散率(p<0.05),加快水分的迁移,提高干燥效率(p<0.05);这是由于干燥初期CMIHA干燥能够显著提高牛肉干不易流动水和自由水的横向弛豫时间(p<0.05),加快内部不易流动水向自由水的转变,不易流动水的含量、信号幅度显著降低(p<0.05),自由水的含量、信号幅度显著提高(p<0.05),促进自由水扩散至物料表面而散失;此外,2种干燥方法对牛肉干干燥过程中结合水的影响差异不显著(p>0.05)。研究结果为CMIHA干燥在牛肉干生产上的应用提供了理论依据。One of the most important processes in food drying is moisture mobility, and different drying methods have different moisture mobility mechanisms. Combined mid-infrared and hot air （CMIHA） drying is a new drying method used in beef jerky that has more thermal efficiency than the hot air （HA） drying often used in Chinese factories. To investigate the reason why CMIHA drying could reduce more time consumption than HA drying, the moisture mobility mechanism of CMIHA drying was studied in this paper. Based on early research, mid-infrared wavelength 2.8-3.1μm, drying temperature 70℃, radiation distance 8 cm, radiation intensity 0.48 W/cm2 and wind velocity 1m/s were selected to study the moisture mobility mechanism of CMIHA drying by comparing to those of HA drying （temperature 70℃, radiation distance 8 cm, wind velocity 1 m/s）. The Shrinkage rate, moisture diffusivities, and heat transfer characteristic were determined to research the moisture mobility of CMIHA drying from a macro-perspective. Based on the low field nuclear magnetic resonance （LF-NMR） that included magnetic resonance spectroscopy （MRS） and magnetic resonance imaging （MRI）, the transverse relaxation time of bound water （T21）,immobile water （T22） and free water （T23）, Peak integral area of different moisture （ A21, A22, A23）, signal amplitude of immobile water （M22） and free water （M23）, and Proton density image of beef jerky were determined to research the moisture mobility of CMIHA drying from the microcosmic aspect. The results showed that, compared to HA drying, CMIHA drying could significantly improve （p0.05） difference in bound water. In conclusion, based on the macro-indexes and microcosmic indexes, CMIHA drying can accelerate the process that immobile water changes into free water. This may be caused by high temperature （55℃） that can make the head of myoglobulin and the tail of myosinogen degenerate and the vibration of moisture molecules by absorbing infrared energy, both of which

关 键 词：核磁共振波谱 核磁共振成像 干燥 中红外干燥 水分迁移 牛肉干 

分 类 号：TS251.52[轻工技术与工程—农产品加工及贮藏工程]