关键词: 亲水胶体, 石蒜淀粉, 糊化特性, 溶胀能力, 冻融稳定性, 流变性

Abstract: In order to improve the quality of starch from Lycoris radiate bulbs, the effects of different hydrocolloids on properties of starch paste, including swelling capacity, pasting properties, freeze-thaw stability and rheological properties, were studied in this paper. After adding hydrocolloids, the swelling power of starch was decreased, and the solubility of mixed systems was improved except for the addition of konjac gum. All hydrocolloids, especially xanthan gum, suppressed starch retrogradation effectively so that the freeze-thaw stability was enhanced. The pasting properties showed that addition of hydrocolloids increased the peak time and paste temperature, decreased peak viscosity, breakdown and setback, and improved the thermal stability and cold stability of starch. Static rheological studies suggested that the rheological curves could be well fitted to the Herschel-Bulkley equation and that the starch and hydrocolloid blends exhibited a typical pseudoplastic ?ow behavior. Addition of all colloids except gum arabic reduced the thixotropy of starch gels to varying degrees. In dynamic rheological experiments it was found that G’ values of all the systems were larger than their G” values and exhibited a frequency dependence, indicating a typical weak gel properties. Addition of hydrocolloids could keep the internal structure of the starch system stable and enhance its shear resistance. Therefore, hydrocolloids can improve the properties of starch paste to a certain extent, depending on the type and structure of hydrocolloids.

Key words: hydrocolloids, starch from Lycoris radiate bulbs, swelling capacity, pasting properties, freeze-thaw stability, rheological properties