EFFECTS OF BLENDING RATIO OF BULLA AND SEMOLINA AND DRYING TEMPERATURE ON THE QUALITY OF MACARONI

Abstract

Macaroni is one of the most commonly consumed extruded product in Ethiopia. However, there is a limitation of raw material i.e. semolina. Hence, there is a need to complement the semolina with locally under-utilized raw materials to enhance the nutritional aspect and reduce cost of semolina. Therefore, this study was initiated with the objective of investigating the possibilities of mixing bulla flour with semolina for the production of macaroni. The experiment was planned with two factors; bulla flour blending ratios and macaroni drying temperatures. It consisted of fifteen combinations of treatments executed in a completely randomized design (CRD). The bulla flour blending ratios were at ratio of 0, 10, 15, 20 and 25% and the drying temperatures were at 60, 70 and 80oC. The result shows that the proximate and physical properties of bulla flour were 15.42% moisture, 0.87% fiber, 0.88 % ash and 38.02 ° angle of repose and are significantly (P< 0.05) different from values of 11.99%, 0.44%, 0.73% ash and 30.98° of the respective attributes of semolina. The functional properties such as water absorption, swelling power and solubility of bulla flour were 1.47 g/g, 4.09 %, and 16.11% while those of the semolina was 1.29, 2.94 and 10.16, respectively. Increase in the bulla flour proportion resulted in a reduction of optimum cooking time from 10.18 to 7.22 min and it increased water uptake capacity from 127.67 to 143.83% and the cooking loss increased from 5.53 to 10.31%. The increase in the drying temperature of macaroni increased in cooking time and decreased water uptake and cooking loss. With the rise in the proportion of bulla flour the sensory acceptability scores of composite macaroni recorded in a scale of 7 points were decreased from 6.01 to 4.47 in color, from 6.24 to 5.49 for flavor, , from 2.67 to 3.25 in stickiness and from 6.28 to 5.63 in overall acceptability of macaroni product. In conclusion, this study indicates that there is a possibility to produce acceptable macaroni from the blending of bulla with semolina. Also, it might help to optimize bulla utilization and reduce semolina import cost for macaroni production.