Structured water-in-oil emulsions developed with candelilla wax

Candelilla wax (CW) is an efficient gelator of vegetable oils with n-alkanes (≈67%) and terpenoid alcohols (≈23%) as major components. The CW forms oleogels with excellent rheological and thixothropic behavior, mainly associated with the microstructure developed by the molecular self-assembly of n-alkanes. In this study we evaluated the CW emulsifying capacity by developing emulsions at different water to safflower oil (W:O) ratios (40:60, 50:50, 60:40). Initially we developed CW solutions in safflower oil by heating at 90°C for 30 min. After setting the CW oleogel at 25°C, we added the corresponding water proportion (25°C) while stirring for 60 secs with an ultra-turrax type homogenizer set at the higher speed. The W/O emulsions, with final CW concentrations of 0.75%, 1.5%, 2.25%, and 3%, were evaluated as a function of storage time (25°C at 0, 4, 8 and 20 days) for solid content (%SC), water droplet size distribution (WDSD), microstructure, and emulsion stability. The results showed that at all CW concentrations studied we developed W/O emulsions that showed smaller WDSD as CW concentration increased, and larger WDSD as the W:O ratio increased. The emulsion stability, thermal, and microstructural analysis of the W:O emulsions and corresponding oleogels (no water added) showed that CW developed structured emulsions (Fig. 1). During emulsification terpenoid alcohols acted as emulsifiers at the oil-water interface, while n-alkanes remained in the oil phase developing an oleogel. The structured W/O emulsions were particularly stable ( > 20 days) at CW concentrations above 0.75% and at W:O ratios below 60:40. The CW structured W/O emulsions showed a mayonnaise-like visual texture (Fig. 2) with thixothropic and frequency independent rheological behavior useful to develop trans-free, low-fat edible spreads.