POLYPHENOLS, TANNINS AND PHYTATE CONTENTS IN SOME EGYPTIAN LEGUMES AS AFFECTED BY SOAKING AND GERMINATION PROCESSES

Abstract

Nutritional value of pulses is a widely accepted but the presence of antinutritional factors in its composition imposes a restriction in its consumption. Soaking and germination process on the removal or reducing of (total phenolic, tannins and phytic acid) of commonly consumed legumes in Egypt were studied. Four legumes namely faba bean (Vicia Faba ) Giza 843, chickpea (Cicer arietinum) Giza 1, cowpea (Vigna unguiculata) krymy 7 and soybean ( Glycine max ) Giza 111, were investigated. Soaking for 12 hours and germination for different time periods (24, 48 and 72 h) contributed significantly reducing in the total phenolic compounds, tannins and phytic acid content of legumes. Phenolics compounds content of raw legumes were, 370.9, 132.5, 763.4 and 249.4 mg/100g, while, tannin contents were, 684.5, 488.1, 390.9 and 225.5 mg/100g, and phytic acid content was, 1050.6 , 719.2, 987.2 and 1076.2 mg/100g on dry weight basis in faba bean, chickpea, cowpea and soybean, respectively. Soaking for 12 hours significantly decreased the concentration of total phenolics, tannins and phytic acid contents of the investigated legumes by 4.0-22.7, 7.1-26.5 and 7.0-15%, respectively. Germination process for 72 hours reduced total phenolics, tannins and phytic acid contents of studied legumes by 21.4 -56.9, 23.9-64.8 and 54.6-65.0%, respectively . From the obtained results it could be observed that the removal extent of antinutritional factors was increased with the progress of germination periods in all studied legumes .