Study On The Structural And Functional Characteristics Of Waxy Rice Starches And Ultrasonic Modification

In order to explore the structural and functional characteristics of waxy rice starches,and the influence of ultrasonic treatment on the properties of waxy rice starches,14 waxy rice starches were selected for this study.The structural characteristics of waxy rice starches were determined by scanning electron microscopy,X-ray diffraction,FTIR and HPAC.DSC,RVA,rheometer and in vitro digestion were used to determine the functional characteristics of waxy rice starches,and then the relationship between the structural and functional characteristics were studied by correlation analysis.Finally,the effect of ultrasonic treatment on the structural and functional characteristics of waxy rice starches were analyzed by means of the above research methods,so as to provide a basis for the applications and physical modification of waxy rice starches.The main results of this study are as follows:1.Waxy rice starch granule present irregular polyhedra with an average diameter of about 5?m.The X-ray diffraction patterns of starch granule were type A with crystallinity ranged from 25.59%to 31.58%.In the FTIR spectrum,the peak intensity ratios of 1047 cm-1/1022 cm-1 were 1.45-2.03,and the granular surface was highly ordered.The average contents of fb1,fb2 and fb3 in amylopectin was 21.82%,45.77%,13.42%,18.77%,respectively.The contents of fb2 and fb3 was higher than that of non-waxy rice starch.2.The To,Tp,Tc and ?H of waxy rice starches were:58.20-73.61 ?,65.86-78.44 0C,75.19-91.50 ?,13.83-20.14 J·g-1,waxy rice starch has high gelatinization temperature and ?H compared with non-waxy rice starch;PV of waxy rice starches ranged from 172.2 RVU to 272.5 RVU,HPV from 72.1 to 134.4 RVU,CPV were 102.5-166.5 RVU,BD were 100.1-179.1 RVU,SB were 30.4-67.2 RVU.Waxy rice starches had high contents of RDS and low contents of RS.3.Correlation analysis showed that fa was negatively correlated with gelatinization temperature and enthalpy of gelatinization,and positively correlated with BD.fb1 was positively correlated with To,Tp,GT and PT;fb3 and Tc,?H were positively correlated.And showed that the chain length distribution of amylopectin was the main factor affecting the physicochemical and functional characteristics of waxy rice starches.4.Results showed that changes were occured in waxy rice starches after ultrasonic treatment,that is,the surface of the starch granules was cracked,the amylose content increased,the degree of crystallinity decreased,the ratio value of(1047 cm-1/1022 cm-1)increased initially and then decreased,the elastic modulus decreased,the gel strength decreased,the value of Tc-To decreased,and the contents of RDS and RS increased.