干热处理对荞麦淀粉物化和结构特征的影响

Effects of Dry Heating Treatment on Physicochemical and Structural Properties of Buckwheat Starch

为了扩大荞麦淀粉在食品领域的应用,研究干热处理对荞麦淀粉物化特性和结构的修饰效果,将荞麦淀粉分别于120、130、140、150、160、170℃干热处理30 min。结果表明:干热处理使荞麦淀粉的峰值黏度、最终黏度等RVA相关黏度参数、起糊温度、凝胶化起始温度、凝胶化峰值温度、凝胶化焓值、结晶度均降低,温度高于130℃时,干热处理使荞麦淀粉短程有序结构含量增加;170℃处理样品的粒径显著增大,其他温度处理对粒径大小影响不显著;干热处理对荞麦淀粉颗粒形貌影响不大,但温度高于150℃时,淀粉颗粒表面的孔或腔变得模糊;150℃以上干热处理使荞麦淀粉的颜色由洁白色逐渐变为灰白色;干热处理并未引起荞麦淀粉生成新的基团或化学键。

The samples were treated at 120,130,140,150,160℃and 170℃for 30 minutes,respectively.The results indicated that peak viscosity,final viscosity,pasting temperature,onset temperature,peak temperature,gelatinization enthalpy and crystallinity of buckwheat starch were decreased after dry heating treatment.When the temperature was higher than 130℃,the content of short-range ordered structure of buckwheat starch was increased after dry heating treatment.The particle size of the samples treated at 170℃increased significantly,while the particle size of the other samples treated had no significant changes.The dry heating treatment had little effect on the morphology of buckwheat starch granules.When the temperature was higher than 150℃,not only the holes or fissures on the surface of starch granules became blurred,but also the color of the samples changed from pure white to off-white.Neither the new groups nor new chemical bonds were generated by the dry heating treatment.