Structure, functionality, and digestibility of acetylated hulless barley starch

Abstract

Hulless barley starch was extracted and further acetylated using acetic anhydride at different level (3.75, 7.5, 11.25 g/100 g) in this study. The structure changes and functional properties of acetylated hulless barley starches comparing to the native starch were evaluated and analyzed. The shape of granules remained unaltered with cracks formed after modification. Small- (1 μm) and large-sized (20 μm) were observed in four kinds of starches while granule particle sizes distribution changed dramatically. Four hulless barley starches presented A-type x-ray diffraction pattern, with relative crystallinity of 25.6, 27.1, 26.2, and 24.8% for native and acetylated starches. The infrared ratio of 1045/1024 and 1025/995 cm−1, indicated the difference in long-range order of crystallinities and short-range order of double helices. Results observed in swelling power, gelatinization parameters, pasting viscosities, and in vitro digestibility indicated acetylated hulless barley starch’s potential as a functional food additive and a healthy ingredient.