A comparison of physicochemical stabilities of β-carotene-loaded nanoemulsions prepared with different food proteins

Abstract

β-Carotene nanoemulsions (BC-NEs), as potential active ingredients for water-based food systems, were stabilized with different food proteins (whey protein isolate (WPI); or sodium caseinate (SC)). The surfactant Tween 20 was used for comparison or in combination with the food proteins. The influence of heating, freezing, pH, and salts on the physical and chemical stabilities of the BC-NEs was investigated. The BC-NEs were stable to aggregation against heating, NaCl, and neutral pH, but were physically unstable against CaCl2 (WPI: 3.4 µm at > 150 mM; SC: 2.6 µm at > 10 mM) and low pH (WPI: 2.8 µm, SC: 1.3 µm at pH 3). However, the combination of Tween 20 and the proteins effectively prohibited BC-NE droplet aggregation under CaCl2 and low-pH conditions. In the chemical stability tests, BC degradation was significantly slower in the WPI-stabilized BC-NEs (WPI: 52% BC at 8 weeks) than in the others (Tween 20, SC: < 35% BC at 8 weeks) and was fastest at the most acidic pH value (pH 3; < 33% BC at 2 weeks). Therefore, this study provides useful insights into the formulation of functional BC emulsions for the commercial food and beverage industries.