Optimizing the processing conditions and formulation of a banana-vegetables instant soup flour

Abstract

Banana experiences high post-harvest losses of up to 45% and yet the fruit’s nutritional composition is insufficient to favor key products development targeting sensitive age groups such as children below 59 months and above 6 months. The major objective of this research was to develop a nutritionally acceptable soup from bananas. This was done by blending banana flour with carefully selected vegetables to suit the nutritional demands of children between 6 to 59 months. In this study, design expert was used to develop a formulation based on bananas, amaranths, pumpkins, carrots, tomatoes and mushrooms. The selection criteria was based on nutritional, physicochemical and acceptability of the soup using an untrained panel (n=30) and the 9-point hedonic scale. Response surface methodology and Central Composite Design of experiment were used to optimize the most acceptable formulation. The optimal product had a composition of Banana: Amaranths: Pumpkins: Carrots: Mushrooms=42.5:42.5:8:3:5 was obtained using the Desirability Functional Approach to select the highly desirable formulation. The effect of each of the ingredients on functional properties were investigated. The soup made from the optimal formulation had a Gross Energy, protein, Vitamin A, Vitamin C, Zinc, Iron and potassium of 409.31 kCal, 15.7%, 71 RAE µg, 7.299 mg, 13.5 mg, 34.6 mg and 1167.27mg for every 100g of the soup respectively which were in the required range of nutritional demands of children in the selected age group at a desirability index of 0.51. To produce a ready to eat product, the composite was extruded at different moisture (10-20%) and barrel temperature (100-180oC) and the product tested for reconstitution, acceptability and functional properties. Results indicated that increase in temperature reduces reconstitution rate through forming bigger clods. Extrusion destroyed all the flavors in the formulation due to high temperatures thus tampering with consumer acceptability. To improve acceptability, freshly cooked and dried vegetable-chicken flour was recommended and its effect on the soup investigated. Regression models for zinc, fat, protein, Vitamin C, Fiber and Moisture content in the soup were significant (p<0.05) while those for consumer acceptability were not significant (p<0.05). The optimal product had a composition of fat, Vitamin A and Vitamin C of 12.70%, 21.09 mg, and 1110 µg per 100g of the soup respectively. It is therefore recommended that the product be prepared for consumption by children between 6-59 months.