Abstract:Polyphenol molecules can interact with starch molecules and this reaction can affect the digestibility of starch. In order to investigate the effect of interaction between starch molecules and polyphenol molecules on the starch digestibility, six polyphenols including genistein, quercetin, naringin, gallic acid, ferulic acid, and caffeic acid, and rice starch were used to prepare the starch-polyphenol complexes in this study, and the digestibility of the complexes was determined. The X-ray diffraction patterns of rice starch-polyphenol complexes showed diffraction peaks at 13.0° and 20.0°, which indicated that rice starch formed V-type complexes with the six polyphenols mentioned above. Differential scanning calorimetry analysis showed that the complexes exhibited an endothermic peak at 104~113 ℃, which further confirmed the formation of V-type starch-polyphenol inclusion complexes. The starch-polyphenol complex was spherical particles which were loosely aggregated. The molar contents of polyphenols in the complexes formed by rice starch and genistein, quercetin, naringin, gallic acid, ferulic acid, and caffeic acid were 5.59, 1.72, 5.40, 5.57, 2.77, and 6.52 mmol/g starch, which indicated that caffeic acid had the strongest ability to form complex with starch. However, the content of resistant starch in each complex was about 32% and insignificant difference was observed. The above results indicated that the resistance of starch-polyphenol complexes was not only dependent on the polyphenols content in complexes.
