Foods containing anti-nutrient:
Bran of grains and pseudo-grains, all kind of seeds, nuts, legumes, potatoes.
Birds and ruminant animals: phytase enzyme. Partially by soaking, cooking, fermenting, sprouting.
Binding with minerals of food in the gut: deficiency of iron, zinc, calcium and other minerals. Reduces the digestibility of starches, proteins, and fats.
Phytic acid occurs naturally throughout the plant kingdom and is present in considerable quantities within many of the major legumes and oilseeds. This includes soybean, rapeseed and cotton seed. Matyka et al. (1993) reported that about 62-73% and 46-73% of the total phosphorus within cereal grains and legume seeds being in form of organically bound phytin phosphorus, respectively. As phytic acid accumulates in storage sites in seeds, other minerals apparently chelates to it forming the complex salt phytate (Erdman, 1979). Studies by Martinez (1977) revealed that in oilseeds, which contain little or no endosperm, the phytates are distributed throughout the kernel found within subcellular inclusions called aleurone grains or protein bodies. Whole soybeans have been reported to contain 1-2% phytic acids (Weingartner, 1987; Osho, 1993). The major part of the phosphorus contained within phytic acid are largely unavailable to animals due to the absence of the enzyme phytase within the digestive tract of monogastric animals. Nwokolo and Bragg (1977) reported that in the chicken there is a significant inverse relationship between phytic acid and the availability of calcium, magnesium, phosphorus and zinc in feedstuffs such as rapeseed, palm kernel seed, cotton seed and soybean meals. Phytic acid acts as a strong chelator, forming protein and mineral-phytic acid complexes; the net result being reduced protein and mineral bioavailability (Erdman, 1979; Spinelli et al., 1983; Khare, 2000). Phytic acid is reported to chelate metal ions such as calcium, magnesium, zinc, copper, iron and molybdenum to form insoluble complexes that are not readily absorbed from gastrointestinal tract. Phytic acid also inhibits the action of gastrointestinal tyrosinase, trypsin, pepsin, lipase and “-amylase (Liener, 1980; Hendricks and Bailey, 1989; Khare, 2000). Erdman (1979) stated that the greatest effect of phytic acid on human nutrition is its reduction of zinc bioavailability.