Effect of Fermentation, Germination and Combined Germination-Fermentation Processing Methods on the Nutrient and Anti-nutrient Contents of Quality Protein Maize (QPM) Seeds

Abstract

Cereals remain the major components of traditional complementary foods but possess antinutritional factors in addition to nutrients. High  antinutrient content have been linked to poor quality complementary foods and high level of undernutrition among children less than two years. Hence, this study examined the effect of fermentation, germination and combined germination-fermentation processing methods on the nutrient and antinutrient contents of Quality Protein Maize (QPM). Maize seeds were fermented and germinated for 72 hours. A batch of the germinated seeds was further fermented for 24 and 48 hours separately. The raw and processed maize seeds were chemically analysed for proximate, mineral (calcium, iron and zinc) and antinutrient (phytate, tannin, oxalate, saponin, polyphenol and hemaglutinnin) composition. ANOVA was used to detect significant differences. Result showed that the crude protein content of raw QPM seeds increased significantly from 10.04% to 10.44% after  fermentation while it decreased to 9.12% following germination (72 hours)-fermentation (48 hours). Crude fat content decreased significantly with  the treatments (4.70-3.20%). Calcium (10.38-4.23mg/100g) and iron (3.70-1.90mg/100g) contents decreased significantly with all the methods.  Germination and combined germination-fermentation reduced more antinutrients in maize compared to fermentation. Fermented seeds had the least tannin (28-27.5 mg/100g) and phytate (967.5-828.5 mg/100g) reduction while the oxalate (590-646 mg/100g), saponin (425-545 mg/100g) and hemaglutinnin (17.31-19.53 mg/100g) contents increased. Germination-fermentation (24 hours) decreased phytate content by > 90% and retained more iron (79 vs 61%) and zinc (80 vs 74%) than fermentation. Combined germination-fermentation (24 hours) was more effective in antinutrient reduction in Quality Protein Maize seeds. Keywords: Maize, complementary foods, antinutrients, processing