Soybeans phytic acid content

Toda, K. K. Takahashi T. One K. Kitamura Y. Nakamura. Variation in the phytic acid content of soybeans and its effect on consistency of tofii made from soybean varieties with high protein content. / Sci. FoodAgric. 2006, 86, 212—219. 

The ash content of soybeans is relatively high, close to 5 percent. The ash and major mineral levels in soybeans are listed in Table 5-7. Potassium and phosphorus are the elements present in greatest abundance. About 70 to 80 percent of the phosphorus in soybeans is present in the form of phytic acid, the phosphoric acid ester of inositol (Figure 5-5). Phytin is the calcium-magnesium-potassium salt of inositol hexaphosphoric acid or phytic acid. The phytates are important because of their effect on protein solubility and because they may interfere with absorption of calcium from the diet. Phytic acid is present in many foods of plant origin. 

Both the glycolipids and the phospholipids of corn have lower percentages of linolenic acid (18 3) and are more saturated than those in the soybean. In general, cmde corn and soybean lecithins are equal in linoleic acid (18 2) content, but lino-leic acid in corn varies from 42% to 70% depending on the variety of corn. Phytic acid, 88% of which is in the com germ, is extracted as part of the lecithin fraction (32, 37). Elimination of phytic acid in com is desirable because it binds zinc, magnesium, and calcium. 

Additional detail concerning the composition of the egg white biotin-fortified diet and the method for analysis of the zinc content of the diets is supplied in a recent publication by Leucke and Fraker (1979). Diets containing phytic acid or soybean protein contaminated with phytic acid should be avoided since the amount of zinc available for absorption is unknown and phytic acid can chelate metals other than zinc. 

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