Sunflower waxes as natural structuring agents to improve the technological properties of water-in-oil (W/O) high internal phase emulsions (HIPEs)

High internal phase water-in-oil emulsions (W/O HIPEs) are promising fat replacers in food systems. In this work, sunflower wax (SW) or hydrolyzed sunflower wax (SWH) (up to 2% w/w) and a fixed PGPR concentration (0.5% w/w) were used to stabilize emulsions with a high volume fraction of water dispersed phase (80% w/w) and sunflower oil continuous phase (20% w/w). Our results showed that 0.5% (w/w) of SW is able to stabilize the W/ O HIPEs, while at least 1.0% (w/w) of SWH was required to promote the same stabilization effect. Furthermore, increasing wax concentration reduced droplet size of fresh W/O HIPEs. However, regardless of the concentration, similar droplet sizes were found for each type of wax after 7 days of preparation. In addition, emulsions structured with SW showed smaller droplet sizes and, consequently, better kinetic stability for 60 days of storage. Oscillatory rheology results showed that the storage modulus (G') prevailed over the loss modulus (G & DPRIME;) with the addition of waxes to the formulation. This indicates the presence of a more elastic crystalline structure, which was also corroborated by polarized light microscopy. This study sheds new insights on the mechanisms of emulsions stabilization by sunflower waxes and opens the opportunity for the applicability of W/O HIPEs in the development of food structure.

Automated summary

Sunflower waxes were used as stabilizers to prepare W/O HIPEs emulsions with a high volume fraction of water dispersed phase and sunflower oil continuous phase. It was found that 0.5% of sunflower wax could stabilize the emulsion, while at least 1.0% of hydrolyzed sunflower wax was required for the same stabilization effect. Increasing wax concentration reduced droplet size, and emulsions structured with sunflower wax showed better kinetic stability for 60 days of storage.