关键词: 奶白花芸豆, 颗粒形貌, 理化特性

Abstract: The granule structure and basic physico-chemical properties of starch from light speckled kidney bean grown in Heilongjiang province were studied. The amylose content of light speckled kidney bean starch was 37.1%. The starch showed maximum absorbance at 617 nm after complexing with iodine. The starch granules were large and oval in shape and showed an uniform size distribution. The crystal structure of the starch, as indicated by X-ray analysis, belonged to type A. The granularity distribution showed a single smooth peak at 21.12－23.51μm and was in a normal manner. The birefringence cross of starch granules was very obvious and the starch revealed an obvious retrogradation property. In addition, the transparency of the starch gel had no significant change during 0－12 h and 24－48 h, while a significant change was observed during 12－24 h. The freeze-thaw stability was the weakest at the concentration of 2%. DSC results showed that the original pasting temperature was 61.3 ℃ and that the pasting peak temperatures were 73 ℃ and 74.6 ℃, respectively. The complete pasting temperature was 83.4 ℃ and the enthalpy required for complete pasting was 50.55 J/g. The concentration of the starch had a significant effect on viscosity. The critical concentration for the pasting of the starch was 4%.

Key words: light speckled kidney been, granule morphology, physico-chemical properties