Acetylated debranched rice starch: Structure, characterization, and functional properties

Combining biological and chemical methods for the modification of starch is a very interesting prospect. The goal of this work was to investigate the influence of debranching and acetylation on the structure of rice starch (RS), ultimately to improve the function of RS. Our experimental results showed that RS particles can be completely destroyed by debranching. The crystal structure of RS is A-type, but the structure of debranched rice starch (DRS) and acetylated debranched rice starch (ADRS) is B-type. The crystallinity degree of DRS and ADRS was less than that of RS. The surface of DRS and ADRS particles became very rough, marking a complete departure from the surface of smooth RS granules. Acetylation occurred specifically at the sides of DRS granules. The surface hydroxyl numbers of RS increased after debranching and acetylation, and the thermal characteristics changed substantially. Debranching led to an increase in onset temperature from 97.79 to 107.64°C; acetylation improved the freeze-thaw stability and swelling power of both the RS and DRS. The blue value of RS varied from 0.424 to 0.640 due to debranching.