Influence of low molecular weight surfactants on the stability of model infant formula emulsions based on hydrolyzed rice protein

The emulsifying properties of rice protein ingredients, and their behaviour in the presence of other non-protein emulsifiers, are essential to support food applications. The objective of this study was to investigate the influence of different low molecular weight surfactants (LMWS) on the stability of model infant formula emulsions (10 g protein L−1, 35 g soybean oil L−1, 50 g carbohydrate L−1) based on a rice protein hydrolyzate (RPH). Inclusion of CITREM and DATEM, at concentrations greater than 1 g L−1, gave emulsions with mean fat globule diameters (D[4,3]) less than 1 μm with good creaming stability, while lecithin was less effective across the concentration range tested (i.e., 1–3 g L−1). Coalescence of the control emulsion was observed upon both storage (10 d at 4 °C) and heat treatment (95 °C × 5 min). Increasing CITREM concentration increased storage and heat stability of the emulsions, while addition of CITREM at 2 g L−1 facilitated the formation of a very stable product. This study provides a first insight into the potential of hydrolyzed rice protein to be used as a value-added ingredient in the production of nutritional beverages such as infant formula emulsions, and the influence of LMWS on the stability of such products.