Title : Influence of oil and protein type on the stability of model infant formula emulsions
Abstract:
Considering the frequent need to develop new formulations that contain functional appeal to meet the scientific and technological demands, the objective of this study was to evaluate physical properties and stability of model infant formula emulsions composed of different types of oils and proteins. Formulations containing 20, 30, 30 and 40 g L-1 protein, oil, lactose and maltodextrin, respectively, were prepared using either whey protein isolate (WPI), whey protein hydrolysate (WPH), WPI+Lactoferrin (LF) or WPH+LF. The oil phase was composed of high oleic sunflower oil (HOSO), or a mixture of HOSO with medium chain triacyclglycerols (MCT) or coconut oil (CO). Water soluble components were dissolved in deionized water, then emulsions were previously homogenized in a rotor-stator followed by passage through a double stage high pressure homogenizer (30/5 MPa), for 2 cycles. Droplets size, microstructure, viscosity and creaming stability of emulsions were evaluated. Regardless of the type of oil, all WPI emulsions remained stable for 1 day of storage. WPH emulsions were completely unstable from the first minutes, however, WPH + LF mixture allowed to obtain stable emulsions during the first hour. The good stability of the systems containing WPI was related to the smaller droplet size and the monomodal size distribution. LF addition may have promoted a greater interaction between droplets, reflecting in systems with higher viscosity. These stable emulsions could be further spray dryed to be used as functional infant formulas.
