Influence of Soaking and Germination on the Iron, Phytate and Phenolic Contents of Maize Used for Complementary Feeding in Rural Tanzania

摘要

Introduction: In developing countries including Tanzania, complementary foods fed to children are often carbohydrate-based and lack sufficient protein, energy, vitamins and micronutrients. Evidence suggests that the iron contained in foods such as cereals is not fully absorbed and will collect in the colon with the possibility of free radical generation and intestinal inflammation. Plant-based complementary foods have been reported to contain high levels of phytate and phenolic compounds, which impact on iron bioavailability. Phenolic compounds have an inhibitory effect on non-heme iron, making it unavailable for absorption in the intestinal tract. Traditional processing technologies (soaking and germination) are widely used in the Iringa District for making local 'brews'. Objective: The objective of the study was to determine the influence of soaking and germination on the iron, phytate and phenolic contents of maize used for complementary feeding in rural Tanzania. Materials and Methods: Maize grains collected from five Wards in the Iringa District were soaked in distilled water, drained and germinated at 0, 36, 48 and 72 hours then processed into flour. Iron, phytate and phenolic contents were analyzed. Results: Iron content fluctuated with germination time, however a significant (P < 0.05) increase was observed at the 72-hour. Significant (p< 0.05) reductions in the mean phytate contents of the samples (ranging from 8.3 to 34.1% reductions) were observed at the 72-hour germination time. Phenolic contents increased with germination time; there was a significant (P < 0.05) increase at the 72-hour germination time for the samples from all locations. Increases in phenolic contents in the soaked germinated maize ranged from 76.7 to 86.3%. Conclusion: The processing technologies of soaking and germination commonly used in the Iringa District for making local 'brews' could be utilized to enhance the nutritional properties of complementary foods used by infants and young children. An awareness and education program to inform community members about transferring this technology and its usefulness to complementary feeding is recommended.