Effect of fermentation and amylase rich flour on physicochemical and sensory properties of complementary food from Oat, barley and teff

Abstract

Inadequate complementary food is a major cause for the high incidence of child malnutrition, morbidity and mortality in many developing countries. In developing countries like Ethiopia, CF are usually made from starchy staples (cereals) with high viscosity, bulk density and antinutrients content. Literature indicates that there exist several modification techniques that increase nutrient density of CF. The purpose of this study was to evaluate the effects of fermentation and amylase rich flour (ARF) on physicochemical and sensory properties of complementary foods from oat, barley and teff. Experimental materials namely (teff, oat, malted barley and barley) used in this study were collected from Debrezeit and Sinana Agricultural research center, Asella malt factory and Holota local market respectively and prepared in to flour at laboratory.A3x3x3 factorial experiment (fermentation time, cereal type and malt concentration) in three blocks was set up. 2 and 5 % of ARF were added into oats, barley and teff flours and were fermented at room temperature (22-25o C) for 24 and 48 hours at a concentration of 1:3 dilutions (w/v) and samples were withdrawn at 24h interval. Titratable acidity and pH were determined immediately at the end of each fermentation period and the samples were dried at 70°C for 36h. The samples were analyzed for proximate composition, antinutritional factors, and functional properties. The data was analyzed using analysis of variance (ANOVA) by using SAS version 9.2. Results showed that interaction effect of fermentation time, cereal type and ARF concentration had highly significantly (p<0.01) decreasing effect on pH, crude fiber, crude fat, total carbohydrate, phytic acid, tannin, bulk density, water absorption capacity and viscosity. In contrast TA, crude protein, calorific value were significantly (P<0.01) increased. The pH value was ranged between (3.89-6.40) and TA in (%) (0.09-0.80).The range mean values of proximate compositions in(%) were moisture(3.67–6.17),ash(1.75- 2.71),protein(8.12–16.82),fat(1.63–4.55)fiber(1.58 5.96),CHO(71.20-78.18)and Energy in (kcal) (359.33–380.26). The results of anti-nutritional factors in (mg/100g) were phytate (18.63- 175.07), tannin (0.84-42.89).The range mean values of functional properties were, bulk density (0.66g/ml-0.99g/ml), WAC (61.33%-143.12%) and viscosity (235cP-1016.33cP).The panelists ranked that appearance, aroma, taste, mouth feel and overall acceptability of the gruel prepared from oat, barley and teff flour that was subjected to 48h fermentation differ from others and least acceptable. In contrast gruels prepared from oat, teff and barley flour that was subjected to 48h fermentation period were acceptable with higher mean score 4.38, 4.16 and 4.02, for consistency. According to the results of this study, combined effect of fermentation and ARF appeared to be promising food processing method to significantly improve the nutrient and energy density and decrease the dietary bulkiness and viscosity values of CFs. Further research on mineral determination and shelf life study of oat, barley and teff based fermented CFs needs to be conducted in Ethiopia.