Effect of Emulsifier Type, Maltodextrin, and β-Cyclodextrin on Physical and Oxidative Stability of Oil-In-Water Emulsions.

Abstract

The effect of emulsifiers, emulsion stabilizer (maltodextrin, MD), and β-cyclodextrin (BCD) on physical and oxidative properties of oil-in-water (O/W) emulsions (5%, 20%, 40% of oil, w/w) was investigated. Four different emulsifiers were selected based on their structure: two types of protein-based emulsifiers (sodium caseinate, SC; and whey protein isolate, WPI), and two types low molecular weight emulsifiers (LMEWs: lecithin, LEC; and Citrem, CITREM). Physical and oxidative stability of emulsions prepared with these emulsifiers together with MD were compared based on their creaming index (CI), viscosity, droplet size, zeta potential, peroxide and p-anisidine values. LMWE-stabilized emulsions (with LEC or CITREM) had better creaming stability with lower droplet sizes whereas protein-stabilized emulsions (with SC or WPI) had higher viscosities. Droplet size was the lowest when CITREM was used, which increased with increasing oil concentration for all emulsifiers. Formulation with the lowest CI value and droplet size was considered to be more prone to oxidation; therefore, a 1:1 (w/w) combination of CITREM with BCD was used to stabilize the emulsions to improve the oxidative as well as physical stability. Added BCD significantly increased the storage stability of emulsions by reducing CI and droplet size values with a simultaneous increase in the viscosity, both at room temperature and at storage conditions (at 4 and 55 o C). However, the oxidative as well as physical stability of BCD added emulsions were not improved, neither toward heat- nor light-induced lipid oxidation. PRACTICAL APPLICATION: This work investigated the effects of emulsifiers and dextrins on the stability of oil-in-water (O/W) emulsions. Both maltodextrin (MD) and β-cyclodextrin (BCD) addition resulted in enhanced physical stability, the latter being more effective. The findings can be applied to formulate emulsions with improved shelf life within the limits of allowed daily intake (ADI) level of BCD (5 mg/kg bw per day).