Effect of Enzymatic Modification on Starch Content and Digestibility of Oat Flour

To study the effect of enzymatic treatments on the starch content and digestibility of oat flour, the content of amylose, amylopectin and total starch in native oat flour, baked oat flour and enzymatic modified oat flour were determined by dual-wavelength spectrophotometry method, and the content of rapidly digestible starch, slowly digestible starch, resistant starch in different oat flour were determined to evaluate the digestibility of oat flour. The structure and particle morphology of oat flour were analyzed by infrared spectrometer and electron microscope. The results showed that, compared with the native oat flour, the content of amylose, amylopectin and total starch had no significant changes (p>0.05) in baked oat flour. But there were extremely significantly change (p<0.01) in enzymatic modified oat flour, which decreased by 77.97%, 43.55% and 46.19% respectively. The content of rapidly digestible starch, slowly digestible starch, resistant starch had no significant changes (p>0.05) in baked oat flour. But there were extremely significantly change (p<0.01) in enzymatic modified oat flour, which decreased by 82.29%、57.06% and 33.48% respectively. No significant differences (p>0.05) were observed in infrared spectrum and the ratio of characteristic absorbance at 1047/1022 cm^-1 and 1022/995 cm^-1. Large starch granules of baked and enzymatic modification oat flour showed more indentations. The starch by enzymatic modification exhibited a decrease in small granules and the degree of indentations was different. This study demonstrated that enzymatic treatments could cause extremely significant reduction in the content of amylase, amylopectin, total starch, rapidly digestible starch, slowly digestible starch and resistant starch in oat flour (p<0.01), which would result in changes in their physicochemical and digestibility properties.