Enzyme protein binding assay for determining folic acid in fortified cereal foods and stability of folic acid under different extraction conditions

The widespread fortification of cereal foods with folic acid has initiated the development of a faster, easier and more reliable method to determine folate in these foods. An enzyme protein binding assay (EPBA) kit developed by a Commercial Diagnostics Company was used for the analysis of folic acid present in folate fortified foods. The food samples were also analyzed by the microbiological assay for comparison of methods. Results from both methods showed no significant difference (p<0.05) in values and showed high correlation (r=0.89, p<0.001). However, the 95% confidence interval for the lower and upper limit of agreement was high. The addition of 1% ascorbic acid to the extraction medium offered better protection of folic acid against oxidation than foods extracted without ascorbic acid. No definite effect on the folate value was observed when extraction was carried out at two different sets of conditions, 10 min at 100 and 121 °C.