Effect of gamma irradiation and pyrolysis on indigestible fraction, physicochemical properties, and molecular structure of rice starch
Nguyen Duy Lam, Tran Minh Quynh, Tran Bang Diep, Pham Thi BINH, Тран Дай Лам
Abstract
This study aims at evaluating the effect of gamma irradiation and pyrolysis on the physicochemical and structural properties of rice starch. It is found that while in the single mode, the contribution of the pyrolysis to indigestible fraction (IDF) content is 21.74 g/100 g, the irradiation at doses of 10, 30, and 50 kGy gave IDF values of 4.47, 6.63, and 9.89 g/100 g, respectively; in the combined mode (when the successive treatment of the irradiation and the pyrolysis was applied), IDF rise sharply, up to 43.72, 47.95, and 52.24 g/100 g, respectively. XRD patterns and FTIR spectra suggest that single mode of irradiation, pyrolysis as well as their combined mode kept the structure and functional group characteristics of rice starch intact, opening a potential approach toward food and non-food application of irradiation treatment in resistant dextrin production by acidic catalyst-free pyrolysis. Practical applications The results of this study showed that gamma irradiation significantly increased the content of indigestible fraction (IDF) to a high level. Combined treatment of irradiation and pyrolysis caused a series of synergic effects on IDF and water solubility in treated starches. The irradiation effectively promoted the pyrolysis reaction as an acidic catalytic agent, therefore suggest a novel potential for food application of radiation treatment in the production of resistant dextrin at high content by acidic catalyst-free pyrolysis.