Investigation of non-thermal effect during microwave irradiation degumming of hemp

In order to investigate the presence of non-thermal effect and its action during microwave irradiation degumming of hemp,two degumming methods( microwave heating and water bath heating) were designed and undertaken under the conditions of different times and temperatures. The comparison of the dry residual gum contents of the two methods indicated that the action of non-thermal effect during microwave irradiation degumming of hemp. Scanning electron microscope( SEM) examination verified the difference in the fiber apparent structures caused by the two heating methods. The dry residual gum content obtained by microwave heating was lower than that by water bath heating. With the increase of heating time and temperature,the difference in residual gum content between the two methods first increased and then decreased,which indicated that during microwave heating processing,besides the thermal effect like water bath heating,there existed some non-thermal effect which was correlated to heating time and temperature.