Physicochemical characteristics of resistant starch prepared from Job’s tears starch using autoclaving–cooling treatment

Abstract

Job’s tears is an essential cereal with rich nutrients and functional chemical compositions. However, systematic knowledge of its starch content is still lacking. This study sought to investigate the resistant starch (RS) properties prepared from Job’s tears starch by autoclaving–cooling treatment. RS contents for native and autoclave-cooled Job’s tears starches were measured as 8.35%-10.53% and 26.57%-31.65%, respectively. The “Maltese crosses” of RS disappeared, and its morphology exhibited irregular sheet structure with layered strips and gully shapes on the surface. Additionally, the XRD pattern of RS presented a combination of B and V types, and disrupted short-range ordered structure. Compared with native starch, the water solubility, swelling power, light transmittance, and water- holding capacity of RS were higher, whereas its hardness, chewiness, resilience, and gumminess were significantly lower. These results will provide insights into the future study of starch in Job’s tears and application of RS in the food industry.

Keywords

• job’s tears
• resistant starch
• autoclaving–cooling
• physicochemical properties