Dialdehyde starches (DASs) with different aldehyde contents were prepared by periodate oxidation of corn starch, and their antioxidant activity and digestibility were studied and related to their structural characteristics, including morphology, relative crystallinity, average molecular weights, swelling power and solubility. The results revealed that DASs were effective antioxidants as revealed by the 2,2'-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity. A significant positive correlation (r>0.959, p<0.01) was found between the antioxidant effect and the aldehyde contents of DASs at all concentrations. The oxidation of starch increased the rapidly digestible starch (RDS) and resistant starch (RS) contents but reduced the amount of slowly digestible starch (SDS). Correlation analysis indicated that the amounts of RDS and RS were positively correlated to the aldehyde contents of DASs (r=0.973, p<0.01, and r=0.900, p<0.01), whilst the amount of SDS was negatively correlated to the aldehyde contents (r=-0.960, p<0.01). The structural characteristic also plays an important role for the antioxidant activity and digestibility of DASs.
Keywords: Antioxidant activity; Corn starch; Dialdehyde starch; Digestibility.
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