Evaluation of the microbiological method for folacin determination in foods : effect of extraction methods on the folacin content of spinach

The effects of various extraction procedures on the folacin activity in spinach and stability of spinach folates during frozen storage and blanching were studied. Free (FFA) and total folic acid (TFA) were determined by a microbiological method using Lactobacillus casei (ATCC 7469) as the assaying organism. The homogenization method, either using Waring blender or mortar pestle had same effect on releasing folacin from blanehed frozen spinach. The time of blending had no effect on the extractable folacin content of the blanched frozen spinach. However, for the fresh spinach. FFA increased from 55 to 137 ug per 100 gm and TFA from 280 to 357 ug per 100 gm fresh weight when the homogenization time increased from 0 to 30 seconds. (See more in text.)