Effect of fermentation on the physicochemical properties, pasting profile and sensory scores of normal endosperm maize and quality protein maize flours

The aim of this study is to compare the effect of fermentation on the physicochemical properties, pasting profile and sensory scores of flour produced from normal endosperm maize variety and quality protein maize. Two maize varieties were studied; a yellow coloured quality protein maize (QPM) - TZE-YPOP-DT-STR-QPM in comparison with yellow coloured normal maize - SUWAN-ISR. Proximate compositions, mineral element content, some physicochemical properties and particle size analysis of the flour were determined. The pasting profiles as well as sensory scores of the flour samples were determined. The result shows that fermentation significantly (p≤0.05) reduced the protein content of both flour samples though more pronounced in normal maize flour; (7.90 to 6.00%) and (8.40 to 7.15%) for normal maize and QPM, respectively. Iron and zinc contents are high ranging from 4.78 to 68.14 mg/100g and 0.08 to 3.95 mg/100g, respectively. Fermentation reduced the bulk density of both normal maize flour and QPM flour. Yet, FQPM flour had the higher bulk density (0.49 g/ml). Mean particle size of the flour was improved by fermentation as FNM and FQPM were found to have smaller particle size than the unfermented counterparts. The peak viscosity of unfermented flour 58.00 and 45.50 RVU for UFNM and UFQPM are lower than the fermented samples; 197.33 and 135.08 RVU. The sensory attributes and overall acceptability of fermented samples were significantly better than that of unfermented samples at p≤0.05. FQPM is most preferred of all the samples. It can be concluded that fermentation improved the pasting profile and some physicochemical properties desirable in the production of weaning food. Also, the reduction effect of fermentation on some nutrient content of maize is more pronounced in normal endosperm than quality protein maize.