Functional and nutritional characteristics of Bambara groundnut milk powder as an ingredient in yoghurt

Abstract

The aim of this study was to evaluate Bambara groundnut (BGN) milk subjected to spray drying with a view to establish functional, nutritional and physical properties as an ingredient in BGN yoghurt production. BGN milk powder (BGNMP) was successfully produced employing the spray drying technology. Maltodextrin was used as the drying carrier to elevate total solids of BGNM prior to spray drying. There were three levels of maltodextrin (5, 10 and 15%) employed and 10% was ideal. The optimum spray drying parameters were estimated to be the following; inlet temperature (150oC), outlet temperature (74oC), air pressure (3 bars), flow rate (10% or 16mL/min), and air flow (42.9 m3/h). The functional properties evaluated revealed high water solubility capabilities, making BGNMP readily soluble in water, which is one of the most crucial aspects of milk powders. The water solubility index of BGNMP at all maltodextrin levels ranged from 85.15 to 90.25%. There was a significant (p < 0.05) difference amongst BGNMP (5, 10, and 15%) in colour parameters (lightness, yellowness, redness, chroma and hue angle). BGNMP indicated to have a red and yellow colour, but yellow was more dominant. The particle size and particle size distribution of BGNMP ranged from 86.13 to 162.35 μm and 84.04 to 157.0 μm, respectively and did not differ significantly (p > 0.05).