Development of structured W/O emulsions with the use of only candelilla wax

Abstract

We investigated the development of water-in-oil (W/O) emulsions using only candelilla wax (CW), evaluating the effects of different water to CW oleogel ratios (40:60, 50:50, 60:40) and the CW concentration (0.75% to 3%). The emulsions were developed by shearing the systems with an ultra-turrax type homogenizer (60 s at 25°C) at the different water to CW oleogel ratios. After 0 and 20 days of storage (25°C) the emulsions were evaluated through microscopy, rheology, water droplet diameter, emulsion stability, and x-ray diffraction measurements. The results showed that at all water to CW oleogel ratios the surface-active components of the CW (i.e., triterpenic alcohols, aliphatic alcohols, and fatty acids) stabilized the oil–water interface, while the n-alkanes and long chain esters formed an oleogel in the oil phase. Independent of the storage time, all the CW emulsions showed frequency independent rheological behavior. However, after applying a strain within the plastic region the 40:60 and 50:50 emulsions formulated with 1.5% to 3% CW provided the higher elasticity and emulsion stability, even after two freeze-thaw cycles. In particular, the 40:60 and 50:50 emulsions with 1.5% CW had a recovery profile similar to commercial mayonnaise. In contrast, independent of the CW concentration, the 60:40 emulsions showed the lowest recovery profile and highest emulsion instability. These results showed the CW as a multifunctional material capable to develop structured W/O emulsions at room temperature without adding surfactants. The structured W/O emulsions developed by CW could be useful in the formulation of trans-free, stable low-fat edible spreads.