Abstract:This study aimed to investigate the effects of factors like starch milk concentration，autoclaving temperature，autoclaving time and refrigerating time during the autoclave modification of black highland barley starch to resistant starch on the yield，structure and properties of resistant starch，in order to exploit the application value of black highland barley resistance starch in food processing.Initially，autoclaving technology was employed to prepare resistant starch from black highland barley.The effects of starch milk concentration，autoclaving temperature，autoclaving time and refrigerating time on the yield of resistant starch were investigated.A combination of scanning electron microscopy（SEM），Fourier transform infrared spectroscopy（FT-IR）and X-ray diffraction（XRD）were used to structurally elucidate the resistant starch，and determine some physicochemical properties.As the results show，the resistant starch yield from black highland barley was 10.596%at a starch milk concentration of 30%，an autoclaving temperature of 125°C，an autoclaving time of 50 min and a refrigerating time of 24 h.SEM analysis revealed significant changes in both the morphology and crystal structure of the resistant starch as compared to the native starch.The native starch granules are spherical，while the resistant starch is in a lamellar shape.According to the XRD findings，the crystal structure of starch changed from the former type A structure to the type C structure of resistant starch.Physicochemical testing demonstrated that the resistant starch prepared from black highland barley by autoclaving technology had decreased solubility，swelling and light transmittance，as well as increased moisture retention.It also exhibited enlarged granule size and more compact structure，but without changed in the chemical structure.