Fermentation and Lactic Acid Addition Improve Iron Bioavailability of Maize

Abstract

Iron deficiency is the most common nutritional deficiency worldwide. Maize is one of the most important cereal crops for human consumption but the iron bioavailabilty (FeBA) is low due to its high phytate content. The objective of this study was to determine the effects of processing on FeBA in maize foods and elucidate better processing techniques that enhance iron bioavailability. Typical maize foods were prepared to represent different processing techniques: heating (porridge), fermentation (ogi), nixtamalization (tortillas) and decortication (arepas) and iron and phytate contents were measured. FeBA was evaluated using the Caco-2 cell model. Phytate content of maize foods was significantly reduced only by nixtamalization (15%, p=0.03), while iron content was not significantly affected. FeBA, expressed as Relative Biological Value (RBV compared to 100% bioavailability of porridge with FeSO4), was significantly higher in ogi fortified with FeSO4 (145% ± 16, p<0.001), and ogi fortified with reduced iron (42% ± 6, p<0.001). Other treatments had no significant effect. Addition of lactic acid 6mg/g significantly increased FeBA by about 2-fold (p<0.01) in most foods, especially in tortilla. Our results suggest that fermentation, or addition of lactic acid to unfermented maize foods may significantly improve FeBA. This approach is more feasible than adding expensive fortificants with high bioavailability, and may provide a novel approach to improve effectiveness of iron fortification programs. Supported by Iowa State University Center for Designing Foods to Improve Nutrition