Effect of soy fortification on the quality of Mkarango a traditional Kenyan fermented maize meal snack

Abstract

This study aimed at improving the quality and nutrient density of a Kenyan fermented maize meal snack (mkarango) through soy fortification to alleviate protein-energy malnutrition (PEM) in children. Nine variations of the snack were prepared by replacing 0, 30, and 50% maize with soy and fermenting each for 0, 3, and 5 days at ambient temperature. To establish the physico-chemical characteristics, the proximate composition, bulk density, water, and oil absorption capacities and titratable acidity were determined. Consumer acceptability was evaluated using a panel of 55 individuals. Fortification of maize with 50% soy increased protein, lipid, and ash content by 256, 284, and 78%, respectively, while carbohydrates reduced by 30%. Fermentation increased lipids and slightly reduced carbohydrate content. Energy ranged from 1,600 to 1641 kJ/100 g. Oil absorption capacity and bulk density reduced with fortification and fermentation while water absorption capacity increased. Fermentation reduced pH by 29 and 31% after days 3 and 5, respectively. There was no significant difference at p ≤ .05 between liking of the fortified snacks and the conventional mkarango, but increase in number of fermentation days reduced the overall acceptance. All fortified snack variations meet more than half the Recommended Daily Allowance for children aged 0.5 to 10 years. Fortification and fermentation improve nutrient density of snacks in terms of proteins, lipids, and ash as well as the functional properties. Preference for all fortified snacks was above average. The soy fortified fermented snack has the potential to alleviate protein-energy malnutrition in developing countries.

Keywords: children; consumer acceptability; fermentation; fortification; maize meal; soybean.

Figure 1

Total quality of the soybean fortified fermented maize meal snacks. ^{a, b, c, d} demonstrate that values with different letter superscripts differ significantly at p < .05 as assessed by Fisher's least significant test. The dark shaded area is the higher percentile and represents the value above which 75% of the ratings fell. The light shaded area is the lower percentile and represents the area where 25% of the ratings fell. The median is the thin line between the two shaded areas where 50% of the values fell above and 50% below. Overall liking ratings 1 = Dislike extremely, 2 = Dislike very much, 3 = Dislike moderately, 4 = Dislike slightly, 5 = Neither like nor dislike, 6 = Like slightly, 7 = Like moderately, 8 = Like very much, 9 = Like extremely. Consumers n = 60