LACTIC FERMENTATION OF NON-TANNIN AND HIGH-TANNIN CEREALS - EFFECTS ON IN-VITRO ESTIMATION OF IRON AVAILABILITY AND PHYTATE HYDROLYSIS

The effect on iron availability estimated in vitro and phytate hydroly sis was investigated in non-tannin and high-tannin cereals, lactic fer mented as flour/water slurries or gruels. A natural starter culture in itiated fermentation and addition of germinated flour and phytase in t he fermentation process was tested. Lactic fermentation of nontannin c ereals with added flour germinated sorghum seeds or wheat phytase incr eased iron solubility from about 4% up to 9 and 50%, respectively. Soa king flour in water before adding starter culture had a similar effect . The increase in soluble iron was strongly related to enzymatic degra dation of phytate (p < 0.001). The reduction of inositol hexa- and pen taphosphates was about 50% with added germinated flour. Reduction was > 90% after soaking the flour prior to fermentation and almost complet e with 50 mg phytase added. High-tannin cereals showed a minor increas e in soluble iron after fermentation, ascribed to the inhibitory effec t of tannins (both on iron solubility and on enzymatic hydrolysis of p hytate). Lactic-fermented cereal foods have a potential in developing countries to improve iron nutrition.