LAUSR

Abstract Resistant dextrins (RD) were prepared by simultaneous debranching and crystallization with waxy maize starch at 50°C for 7 days, followed by the hydrolysis using an acid (3.16 M sulfuric acid) or ɑ-amylase (5% based on starch solids) for 24 h. The crystallinity, thermal transition, morphology, and in vitro digestibility of the hydrolyzed RDs were analyzed. The RD hydrolysates showed typical A-type crystalline patterns under X-ray diffraction with increases in crystallinity and thermal stability compared to the unhydrolyzed counterparts. The RD crystals were obtained as nano-sized particles by the hydrolysis, which readily aggregated while drying. Based on the in vitro digestibility test, the enzyme-resistant fraction of the hydrolysed RDs was greater than the unhydrolyzed one by 5-10%. Heating in a boiling water-bath (15 min) decreased the enzyme-resistant fraction to less than 50%, while the hydrolysis raised the fraction by 10-15%. The hydrolysis could be used in the preparation of nano-sized RD with increased crystallinity and resistance to the digestion.