Thermal processing. This treatment generally enhances the digestibility of proteins and carbohydrates, although if Maillard browning (The Maillard reaction creates brown pigments in cooked meat in a very specific way: by rearranging amino acids and certain simple sugars, which then arrange themselves in rings and collections of rings that reflect light in such a way as to give the meat a brown color) occurs in baked foods protein quality and digestibility may be reduced (Table 3). Thermal processing may also improve the bioavailability of certain vitamins and I, in some cases because of the destruction of heat-labile anti-nutritional factors (Erdman & PnerosSchneier, 1994). For example, thiaminases in Brussels sprouts and red cabbage, which catalyse the cleavage of thiamin, are destroyed by cooking (Hilker & Somogyi, 1982). Cooking also destroys the goitrogens present in cabbage, Brussels sprouts, turnips, sweet potatoes (Ipomoea batatas), millet (hnatherum hymenoides), cassava (Manihot esculenta Crantz) and beans. Such goitrogens block the absorption or utilization of I and thus its uptake into the thyroid gland (Gaitan, 1990).For example, greater increases in total serum b-carotene and serum lycopene have been reported after eating cooked carrots and spinach (Rock et al. 1998) and cooked tomatoes (van het Hof et al. 2000) compared with levels when they are consumed raw. This effect is attributed to softening or disruption of plant cell walls and the disruption of carotenoidprotein complexes so that the carotenoids are more available in the intestinal lumen for absorption (Yeum & Russell, 2002)

Source: Improving the bioavailability of nutrients in plant foods at the household level

What is phytate? Phytate, myo-inositol hexakisphosphate, is the salt of phytic acid and is widely distributed in all seeds and possibly all cells of plants. It serves as a storage of phosphorous and minerals and accounts for 60-90% of the phosphorous in the plant. Besides phytate, other inositol phosphates are present in the seeds, however to a much lower extent. During the germination of seeds, phytate is hydrolysed, and phosphorous along with minerals such as calcium, magnesium and iron are liberated, becoming available for germination and development of the seedlings.The degradation of phytate will result in an increased bioavailability of minerals and trace elements. Phytate can be degraded during food processing like soaking, germination, malting and fermentation under optimal conditions, as well as with addition of the enzyme phytase that will hydrolyze phytate. The soaking medium used depends upon the type of seed. At optimal conditions for the enzyme phytase (55C, pH 4.5-5.0) phytate could be effectively reduced after 12-16 hours of soaking.Different components that enhance or inhibit iron uptake: Phytic acid, polyphenolic compounds, and milk are the major inhibitors, whereas ascorbic acid enhances iron absorption.Soaking nuts & seedsFor grains, we soak in an acidic solution to get rid of phytic acid. Nuts do not contain much phytic acid but do contain high levels of enzyme inhibitors. The method imitates the way the native peoples in Central America treated their nuts and seedsby soaking them in seawater and then dehydrating them.