Development Of Cowpea-Fortified Weaning Food; Consumer Expectations, Functional And Chemical Properties

Abstract

Questionnaires were administered to a hundred and thirtytwo mothers (132) selected at random at four (4) mother and child welfare clinics in Accra in order to obtain their views and expectations of cowpea-fortified weaning formulations. Majority of these mothers (>80%) prepared infant weaning porridges from raw ingredients, eg. fermented maize dough, and were willing to incorporate cowpea into their infant porridges and other foods if it was available as a raw or pre-cooked flour on the market. Factors that motivated the mothers in the selection of an infant weaning food included the cost and nutritional value of the product. The child's acceptance of the food, usually maintained its continued use. Germinated cereal flours (of maize, millet and sorghum) were added to 3-day fermented maize dough in attempt to degrade the starch by the action of alpha and beta- amylases in the cereal malt and thereby reduce its bulk density. The cereals were sprouted for 2,3 and 4 days and then incorporated into fermented maize dough at concentrations of 5% and 10% (dry matter basis). Sorghum malt in comparison to millet and maize malts was not effective in terms of lowering the hot and cold paste viscosities of the fermented maize dough. Millet and maize malts liquified the dough considerably. The effect of 4-day sprouted cereal malt was most pronounced whilst the optimum activity of maize malt observed after three days of sprouting. The effects of maize dough fermentation and its fortification with steamed cowpea on proximate as well as oligosaccharide composition, physicochemical and functional characteristics were also studied. A 5x4x2x2 factorial experiment with cowpea level (0, 5, 10, 15, 20 %) , fermentation time (0, 24, 48 72 h) , fermentation method (single-component and multi-component) and cowpea steaming time (0, 4 min) as the variables was performed. The cowpeas were dehulled, steamed, dried at 65 °C for 24 h and milled into flour. Maize was soaked in water (18 h) , drained and milled into flour. The maize-cowpea blends were made into a 50% moisture dough, fermented for the specified periods, dried at 65 °C and milled into flour. Moisture, protein, ash and fat content were measured Stachyose, raffinose and other sugars were extracted from the samples and analyzed using High Pressure Liquid Chromatography (HPLC). The protein content of the maize-cowpea blends increased with level of cowpea in the blend; the ash and fat contents were not influenced by process variables. The pH of the samples were affected by fermentation time, steaming and the level of cowpeas in the blend. Cowpeas was the main source of sucrose, stachyose and raffinose and maize the source of glucose/galactose. Fermentation caused , a reduction in stachyose and glucose/galactose. The mixing of cowpea flour with fermented maize dough prior to drying (single component fermentation) gave similar effects on sugar concentrations as detected in the cofermented samples (multi-component fermentation). Fermentation can therefore reduce anti-nutritional factors and non-digestible components in legumes. The process can be used to develop acceptable weaning foods from maize-cowpeNa blends. Models were developed to predict Brabender viscosity from Brookfield viscosity determined at various spindle speeds (10, 20, 50rpm), solids concentration of samples and temperatures. R2 of the models could explain 95.32% - 98.32% of the variation observed. There was high correlation (R = 84.51% - 95.97%) between the viscosity measurements made by both instruments.