康卫氏皿扩散法测定黄米粉的水分活度

运用康卫氏皿扩散法测定了黄米粉的水分活度,结果表明:用氯化镁、碳酸钾、氯化钠、氯化钾四种盐的饱和溶液构成的四元体系,实验数据标准偏差较小,精密度高.黄米粉的水分活度会随着粒度的变小逐渐增大,但增大幅度比较小.在25℃,经过2 h的水分交换平衡,测定出粒度为80、100、120目的黄米粉的水分活度分别为0.600、0.610、和0.619.

Determination of water activity in broom corn millet flour by way of Conway＇s dish diffusion method

The water activity in broom corn millet flour was determined Conway＇s dish diffusion method.It shows that the standard deviation of experimental data was smaller and have high accuracy when using quaternary systems composed of saturated solution of magnesium chloride,potassium carbonate,sodium chloride and potassium chloride.Water activity in broom corn millet flour increases as the particle size decreases,but the extent of the increases is relatively small.At 25 ℃,after 2 hours of water exchange equilibrium,it was determined that the water activities reaches 0.600,0.610,and 0.619 respectively for the particle size of 80 mesh,100 mesh and 120 mesh of broom corn millet flour.