Indigestible pyrodextrins prepared from corn starch in the presence of glacial acetic acid.

This study was conducted to evaluate the feasibility of using acetic acid (0-2.5%) as the catalyst in the production of pyrodextrins from corn starch at 140-180 °C, and to elucidate the effects of catalyst concentration and pyrolytic temperature on the characteristics of indigestible pyrodextrins. In the absence of acetic acid, noticeable changes to the loss of birefringence, increased solubility, plateau of molecular weight reduction, decreased reducing sugar content and digestibility were observed at 180 °C. By using catalyst, the alterations in the aforementioned characteristics of pyrodextrins were intensified. Moreover, by using 0.5-1.0% catalyst, the substantial alterations in birefringence, solubility and molecular weight were observed concurrently for pyrodextrins formed at 170 °C. Further increasing the concentration of acetic acid to 1.0-2.5% decreased the intervening temperature to 160 °C. The findings suggest that indigestible pyrodextrins with desired characteristics could be tailored via using various combinations of catalyst concentration and pyrolytic temperature.