羊肉风干过程中微观结构变化研究

Study on Microstructure Changes of Mutton During Air Drying

通过苏木精-伊红染色、扫描电镜、透射电镜观察并测定了小尾寒羊半膜肌在35℃风干过程中孔隙率、肌细胞间隙、肌细胞面积等的变化规律,利用热电偶测定了风干过程中风干肉表皮和内部温度的变化,以期为风干过程中传热传质等研究奠定基础。结果表明:随着风干的进行,风干肉表皮和中心的温度逐渐上升,表皮的温度上升速度更快;当水分含量降低至45%时,肌细胞面积显著减小,其他水分含量下肌细胞面积变化不显著,风干肉的肌细胞间隙、孔隙率表现出先减小、再增加、最后减小的趋势,这可能和结缔组织、肌细胞收缩不同步有关。扫描电镜发现结缔组织结构完整,肌纤维收缩,但并未发现结缔组织和肌细胞之间孔隙变化。随着水分含量降低,透射电镜观察到基底膜和肌细胞分离。综上所述,随着水分含量的降低,风干肉的微观结构受到了结缔组织和肌细胞收缩共同的影响,导致孔隙率先减小、后增加、再减小,苏木精-伊红染色法更适合用于研究风干过程中孔隙率的变化,扫描电镜更适合观察结缔组织结构完整性,透射电镜更适合观察结缔组织与肌细胞的分离。

In this study,hematoxylin-eosin staining,scanning electron microscope and transmission electron microscope were used to measure the changes of porosity,space of muscle cells and muscle cell area of semimembranosus of Small-Tailed Han Sheep during air drying at 35 ℃.Thermocouple was used to measure the changes of skin temperature and internal temperature of meat during air drying.The results will laid a foundation for the studies including heat and mass transfer during air drying.The results showed that:with the progresses of air-drying,the temperature of the surface and center of the dried meat rose gradually,and the temperature of the surface rose faster.When moisture content was 45%,the muscle cell area significantly decreased,but there was no significant change between other air dried meat with different moisture content.The space of muscle cells and porosity of air-dried meat decreased first,then increased,and finally decreased,this could be related to the unsynchronized shrinkage of connective tissue and muscle cells.The contraction of muscle fibers and intactness of connective tissue structure were observed by scanning electron microscopy,but the changes of pores between connective tissue and muscle cells were not found.With the decrease of moisture content,the separation of basement membrane and muscle cells was observed by transmission electron microscopy.In conclusion,with the decrease of moisture content,the microstructure of air-dried meat was affected by the contraction of connective tissue and muscle cells,resulted in the first decrease in porosity,then increase,and then decrease.Hematoxylin-eosin staining(HE) staining was more suitable for studying the changes of porosity during air drying,scanning electron microscope was more suitable for observing the structure of connective tissue,and transmission electron microscope was more suitable for observing the separation of connective tissue and muscle cells.