Journal Article

Impact of Fermentative Modification of Maize Grain Biopolymer on Functional Properties, Proximate Composition, Amino Acids Profile and Protein Quality of Maize Flour

Abstract

Fermentative modification of maize grain biopolymer led to a significant reduction in Water Absorption Capacity (WAC), Gelatinization Temperature (GT), Swelling Capacity (SC) and Bulk Density (BD) of the modified flour, but a 17.9% increase in Least Gelling Concentration (LGC) was observed due to a decrease in the “network-forming-units” of the modified maize biopolymer. The process also led to a significant reduction in the percentage ash and fat contents of the flours by -50% and -65% respectively An increase in protein content by more than 42% was recorded and a slight reduction in total carbohydrates and energy value of -1% and -2% respectively were observed. Fermentative modification has improved the percentage values of all the amino acids in the modified maize flour leading to a general improvement in protein quality. Nutritional Index (NI) of the modified maize flour was improved by about 130% which is quite remarkable considering the relative ease and the cost effective way the process was achieved. The improvement in Biological Value (BV) was most remarkable as almost 3000% increase was recorded. Protein Efficiency Ratio (PER) was improved by 72.4%, while the Essential Amino Acids Index (EAAI) was improved by 61.4%. Of the essential amino acids, tryptophan recorded the highest percentage increase in chemical score (142.3%) as a result of fermentative modification. The increase in chemical scores of methionine, leucine, histidine and isoleucine, in that order, were 94%, 74.9%, 69.9%, and 66.6%. Lysine and valine recorded considerable increase of more than 50% in their chemical score while phenylalanine and threonine recorded the least increase with 8.7% and 4.5% respectively

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