Formation and physical stability of hazelnut oil nanoemulsions: Comparison of a synthetic surfactant and a natural emulsifier

Abstract

AbstractHazelnut oil is a significant edible oil with positive effects on human health. This study aimed to integrate hazelnut oil, which is known for its cardiovascular benefits, into nanoemulsion technology for the first time as an innovative conception, to maintain its stability against environmental conditions, and to benefit more by making it more bioaccessible. Polysorbate 80 and whey protein isolate (WPI) were used to stabilize the nanoemulsions. In this way, we aimed to show that WPI, a natural emulsifier, could be an alternative to the synthetic Polysorbate 80 emulsifier known for its high emulsification ability to stabilize hazelnut oil emulsions. The emulsions, formed by using a 2% (wt/wt) emulsifier and passed through a microfluidizer five times at 96.5 MPa pressure provided the small particle size (d32) as 296 ± 7.76 nm and 216 ± 1.78 nm for the WPI and Polysorbate 80‐stabilized samples, respectively. Polysorbate 80‐stabilized nanoemulsions were more physically stable under different pH, temperature, and ionic strength conditions compared with WPI‐stabilized nanoemulsions. Finally, the fates of the emulsions were investigated under a simulated in vitro digestion system. The increase in droplet sizes during the gastric phase was to a higher extent for the WPI‐stabilized nanoemulsions (d32 = 5.500 ± 0.60 μm) compared with Polysorbate 80‐stabilized emulsions (d32 = 1.069 ± 0.09 μm). Although hazelnut nanoemulsions stabilized with Polysorbate 80 showed higher physical stability, it was determined that WPI would also be successful in producing stable hazelnut oil‐in‐water emulsions, exhibiting FFA (%) values of 88%–90.5% in the small intestine.