红小豆和红花豆淀粉热性质及回生性质的比较

A Comparative Study of Properties of Starches from Red Kidney Bean and Red Azuki Bean

以红小豆和红花豆为研究对象,分析比较了两种淀粉的化学组成、颗粒形状、结晶性质、热性质及回生性质。SEM结果表明,大颗粒红小豆和红花豆淀粉大颗粒成肾状或卵形,小淀粉颗粒成球形;XRD试验结果表明,红小豆和红花豆淀粉结晶类型为A型,结晶衍射峰2θ角均在15.0°,17.0°,19.0°和22.8°左右;DSC扫描结果表明,红小豆和红花豆淀粉的熔点温度分别为62.12℃±0.29℃和62.17℃±0.22℃,峰值温度分别为68.87℃±0.22℃和68.76℃±0.31℃,糊化焓变值分别为11.73±0.62 J/g和14.63 J/g。回生试验结果表明,红小豆和红花豆淀粉凝胶在4℃贮藏期间,回生淀粉熔点和峰值随时间延长而下降,回生焓变随时间延长而增长,红小豆和红花豆淀粉凝胶在7 d时重结晶过程基本结束,且与直链淀粉含量相关。因此,在工业应用中可以通过测定淀粉热性质来预测其用途,也可通过控制淀粉基食品中直链淀粉比例加速或抑制淀粉基食品老化过程,进而提高淀粉基食品的食用价值。

The chemical composition, morphology, crystallinity, thermal and retrogradation properties were evaluated and compared. SEM results indicated that large granules of red kidney bean and red azuki bean starches were kidney-shape or oval, and small granules were spherical. XRD results showed that the crystallinity patterns of red kidney bean and red azuki bean starches were A-type, and the intensity peaks were near 15.0°, 17.0°, 19.0° and 22.8° （20）. DSC results suggested that the melt and peak temperatures, and thermal enthalpy of red kidney bean and red azuki bean starches were 62.12℃±0.29℃ and 62.17℃±0.22 ℃, 68.87℃±0.22℃and 68.76 ℃±0.31℃, 11.73~0.62 J/g and 14.63 J/g, respectively. The melt and peak temperatures of red kidney bean and red azuki bean starches decreased with storage time extend, however, the retrogradation enthalpy increased during the storage time. Moreover, the retrogradation process finished within 7 d of storage, which was related to amylose content. Therefore, its potential useful applications could be developed by evaluating the thermal properties and retrogradation properties or by controlling the amylose ratio of starches.