Proximate composition and selected functional properties of complementary foods from teff fortified with soybean and orange-fleshed sweetpotato

The proximate composition and selected functional properties of teff-based extruded and traditional complementary foods (CFs) were evaluated. For extrusion, teff, soybean and orange-fleshed sweet potato (OFSP) were separately processed into their respective flours and mixed in a percentage ratio of 70:20:10, respectively. The mixture was then extruded into a complementary food (ComF1). For traditional methods, portions of teff grains separately germinated for 24 and 48 h were dried and ground. Similarly, small portions of soybean grains were separately blanched, roasted and then each ground to fine flour. Four traditional CFs (ComF2, ComF3, ComF4, ComF5) were developed by blending flours of ungerminated teff, germinated teff, blanched or roasted soybean and OFSP using the same ratios (70:20:10). The blending resulted in a higher protein (12.94 g/100 g) and fat (8.68 g/100 g) contents. Extrusion significantly (p < 0.05) increased the protein content (17.92 g/100 g) but decreased the fat (6.22 g/100 g) whereas the traditional methods did not affect them. Energy content of the CFs ranged from 391.63 to 400.60 kCal/100 g. All CFs met the requirements of protein and energy for 6-8 months old infants. The bulk density and water absorption index of the CFs were significantly lower. The highest water solubility index was found for ComF1 (16.63%), and the in vitro protein digestibility of ComF1 was significantly (p < 0.05) high (87.62%). The study revealed the potential of developing weaning products from teff, soybean and orange-fleshed sweet potato that are both nutritionally and functionally desirable despite a few anomalies.