康卫氏皿扩散法测定荞麦粉的水分活度

Determination of Water Activity in Buckwheat Flour by Way of Conway's Dish Diffusion Method

[目的]测定不同粒度荞麦粉的水分活度,为荞麦粉这种食品原料的储存和加工提供基础数据。[方法]运用康卫氏皿扩散法测定荞麦粉的水分活度。[结果]用氯化镁、碳酸钾、氯化钠、氯化钾4种盐的饱和溶液构成的四元体系,试验数据标准偏差较小,精密度高。荞麦粉的水分活度会随着粒度的变小逐渐增大,但增大幅度较小。[结论]在25℃,经过2 h的水分交换平衡,测定出粒度为80、100、120目的荞麦粉的水分活度分别为0.585、0.599和0.608。

[Objective] The water activity in different size buckwheat flour was determined to provide buckwheat flour storage and processing with basic data.[Method] The water activity in buckwheat flour was determined by way of Conway＇s dish diffusion method.[Result]The standard deviation of experimental data was smaller and had high accuracy when using quaternary systems being composed of saturated solution of magnesium chloride,potassium carbonate,sodium chloride and potassium chloride.Water activity in buckwheat flour will be increased as the particle size decreases,but the extent of the increases is relatively small.[Conclusion] At 25 ℃,after 2 hours of water exchange equilibrium,it was determined that the water activities were 0.585,0.599,and 0.608 respectively for the particle size of 80 mesh,100 mesh and 120 mesh of buckwheat flour.