大豆分离蛋白/壳聚糖共混膜热力学性能

采用差示扫描量热法(DSC)研究了成膜基质比例、增塑剂丙三醇体积分数和pH值对大豆分离蛋白(SPI)/壳聚糖(CS)共混膜热力学性能的影响。结果表明:共混膜较相同条件下SPI和CS单纯膜的结构更加稳定,成膜基质比例SPI∶CS=1∶1时共混膜交联度最高,热稳定性最好;增塑剂丙三醇体积分数的提高可降低共混膜放热峰的高度,增加放热峰的宽度,但是玻璃化转化温度和熔融温度随之降低;当pH值在1～3时,共混膜的玻璃化转化温度、熔融温度和结晶度值均较低,pH值在4～6时,各值升高,共混膜的热稳定性较好。

Thermodynamic properties of the soy protein isolate and chitosan blend film

The effect of the film-forming ratio,glycerol concentration and pH value on the thermal properties of the soy protein isolate(SPI) and chitosan(CS) blend film was studied by adopting the differential scanning calorimetry(DSC).The results show that the structure of the blend film is more stable than that of the SPI and CS single film at the same condition,the degree of cross linking of the blend film achieves the maximum when the film-forming ratio is SPI∶CS=1∶1,at which the thermal stability of the blend film is optimal.The increase of the glycerol concentration can lower the height of the blend film exothermic peak and expand the width of the peak,but the glass transition and melting temperatures decline correspondingly;the degree of crystallization of the blend film,glass transition temperature and degree of crystallinity all remain lower when the pH value is in the range of 1～3;the three values ascend and the thermal stability of the blend film is superior when the pH value is in the range of 4～6.