Abstract:

A high-pressure micro-fluidization homogenizer for nano-sized products was used to treat the solution of kidney bean （ Phaseolus vulgaris L. ） protein isolate （KPI）. The effects of micro-fluidization treatment at different pressures on the conformational and functional properties of KPI were then investigated by means of solubility and turbidimetric measurements, DSC, fluorescence spectroscopy, UV spectroscopy and Far-UV circular dichroism （CD） spectroscopy. The results indicate that the micro-fluidization treatment leads to the transformation of insolu- ble aggregates into soluble ones, thus improving the solubility （PS） and the emulsifying activity index （EAI） of KPI. It is also found from the fluorescence emission spectra and the Far-UV CD spectrum that micro-fluidization treatment has no obvious effect on the tertiary and secondary structures of the proteins. Moreover, according to the DSC results, the thermal stability and structure orderliness of KPI show no obvious change after the micro-flui- dization treatment.

Key words: kidney bean （Phaseolus vulgaris L. ） protein, miero-fluidization, functional property, conformation