Comparison of colorimetric methods for determination of phytic acid content in raw and oil extracted flour samples of maize

Abstract

There are different colorimetric methods, with various analysis principles and phases, for the estimation of phytic acid content in agricultural products. Maize genotypes may possess a wide range of oil content, which is considered as a factor affecting the results of phytic acid analyses. Elaborative studies are needed to examine these methods to clarify the effect of oil content on the results, especially in the sample sets with varying oil concentrations. We utilized 4 different colorimetric methods; namely, AOAC, Wade, Chen and Haug-Lantzsch (H-L), to estimate phytic acid content in 19 maize genotypes, classified as having high (>7 %, n = 7) normal (3–5 %, n = 6) and low (<3 %, n = 6) oil content. Phytic acid determination was carried out on 2 groups of flour samples (raw: E1, and oil extracted: E2) using 3 replications. The results indicated that analysis methods yielded rather different phytic acid values. They also differed significantly in time and cost, with the Chen method being the cheapest and Haug-Lantzsch (H-L) the quickest. Oil extraction had significant effects on phytic acid results, and these effects varied across the analysis methods and the oil content of the genotypes. Our data suggest that either novel or improved colorimetric methods are necessary when analyzing phytic acid in special maize genotypes, considering the dissimilarity of the results from the current methods.