粒度大小对大米RVA谱的影响

Effect of particle size of milled rice on its RVA spectrum

将3种市售大米粉碎成不同粒度的样品,通过测定它们的黏度值,研究粒度大小对大米RVA谱的影响。结果表明,粒度必须达到一定的细度后才能测出具有代表性的黏度值,如样品粒度较大,需在RVA仪程序中给予充分的时间才得到完整的曲线;峰值黏度、最低黏度、最终黏度随着大米粒度逐渐变小而呈先升后降的趋势,回生值随着大米粒度减小而减小,衰减值呈逐渐增加的趋势;并建立了粒度与RVA谱各特征值关系的回归方程,且粒度大小对不同种类的大米影响相同。

Three types of milled rice sold in market were ground to prepare samples with different particle sizes and then their viscosity values were determined respectively to study the effect of particle size of milled rice on its RVA spectrum. The results showed that the representative viscosity values could be detected only when the particle size reached certain fineness. If ihe particle size of the samples was bigger, the sufficient time should be given in the operation procedure of RVA meter for obtaining the complete data curve. The peak viscosity, trough viscosity and final viscosity increased first and then decreased along with gradual decrease of milled rice particle size. The setback viscosity decreased along with decrease of milled rice particle size and the breakdown viscosity trended to gradual decrease. The regression equation between the milled rice particle size and the viscosity was established. The particle size showed the same effect on RVA spectrum of different types of milled rice.