不同杂粮淀粉物性的研究

为丰富和拓展特色杂粮深加工技术和品质控制方法,以莜麦、高粱、薏苡、小米和甜荞5种特色杂粮淀粉为对象,进行色度、粒径、直链淀粉含量、溶胀度及流变性等特性的研究。结果表明,5种淀粉L*值为94.34~97.15,符合淀粉色度要求,平均粒径分布介于1.572~16.989 μm。淀粉中直链淀粉含量为5.08%~30.97%,存在显著性差异(P<0.05)。热学特性方面,莜麦淀粉的峰值温度Tp、终止温度Tc和糊化焓△H显著低于其他淀粉(P<0.05)。淀粉溶胀性与温度有关,随温度增加而增大,95 ℃薏苡淀粉溶胀度最大为20.282 g/g,但其冻融析水率最低。流变性分析发现,5种淀粉糊均为假塑性流体,表现出剪切稀化特性。综合分析,不同种类杂粮淀粉的物理特性间存在差异性,应根据加工目的选择适合的淀粉,并为淀粉的深加工与品质控制提供理论依据和参考。

Research of Physicochemical Properties of Different Coarse Grain Starches

In order to enrich and expand the deep processing technology and quality control methods of characteristic coarse cereals,the chrominance,size,amylose content,pasting properties,and rheological characteristics of starches from millet,buckwheat,sorghum,avena chinensis and coixan were investigated in Shanxi province.The results showed that the L* parameter of five starches were in the range of 94.34 to 97.15,which met the requirements of starch color.Moreover,on the basis of particle size,the five starches ranged from 1.572 μm to 16.989 μm,and the granules of millet starch was the smallest.The amylose content of samples tested were significantly different among cultivars (P<0.05),which ranged from 5.08% to 30.97%.In terms of thermal properties,gelation temperatures (To,Tp and Tc) and enthalpy (?H) of avena chinensis starch were significantly lower than those of other starches (P<0.05).The swelling power of starches were temperature-dependent,but it showed non-linear increase with temperature.When the pasting temperature rose to 95 ℃,the swelling degree of coixan starch was 20.282 g/g,but its freeze-thaw water condensation rate was the lowest.Rheological analysis showed that five kinds of starch pastes were pseudoplastic fluid,showing shear thinning characteristics.According to the comprehensive analysis,there were differences in the physical properties of different kinds of coarse cereals starch.The suitable starch should be selected according to the processing purpose,and provide theoretical basis and reference for the further processing and quality control of starch.