Effect of lactose-to-maltodextrin ratio on emulsion stability and physicochemical properties of spray-dried infant milk formula powders

This study was conducted to investigate the effects of lactose-to-maltodextrin ratio (L:M 100:0, 85:15 and 70:30) on emulsion stability and the physicochemical properties of spray-dried infant milk formula. Lactose-to-maltodextrin ratio did not affect the emulsion particle size, but increasing the proportion of maltodextrin increased the apparent viscosity after evaporation and decreased the zeta potential of emulsions. Most importantly, increasing maltodextrin proportion increased the glass transition temperature (by 4 and 8 degrees C at 15% and 30% maltodextrin, respectively) and decreased the crystallinity and yellowness of the powders. Surface composition of powders was different to that of their bulk composition, where fat was over-represented on the powders surface (similar to 41-44%), followed by protein (similar to 30-33%) and carbohydrate (similar to 24-26%). This study concludes that maltodextrin can be successfully included in infant formula blends without affecting emulsion stability in a wet mix and allows controlled modifications of certain properties in corresponding spray-dried powders.