Abstract:

This paper deals with the influences of frozen mode and frozen time on the secondary structure of wheat gluten proteins by means of circular dichroism spectroscopy. The results show that the secondary structure of the non-frozen gluten proteins in SDS solution is mainly composed of β sheets and random coils,that the two adopted frozen storage modes have no obvious effect on the secondary structure of the gluten proteins when the frozen time is less than 60 d,and that,in the thermostatic frozen storage mode,the secondary structure obviously changes after a storage for 90 d,the α helixes of the soluble gluten proteins turn into β sheets and β turns,and the β sheets and the β turns of the insoluble gluten proteins turn into α helixes and random coils. However,in the freeze-thaw storage mode,the secondary structure significantly changes after a storage for 60 d,the α helixes of the soluble gluten proteins turn into β sheets and random coils,and the β sheets and the β turns of the insoluble gluten proteins turn into α helixes and random coils. Thus,it is concluded that,in the thermostatic frozen storage mode,the secondary structure of the gluten proteins changes only when the frozen time is equal to or greater than 90 d,while in the
freeze-thaw storage mode,the storage only for 60 d may affect the secondary structure.

Key words: frozen storage, gluten protein, secondary structure, circular dichroism spectroscopy