Neobee 1053 medium chain triglycerides (MCTs) is caprylic/capric triglyceride oil with a fatty acid distribution of 55% of C8:0 and 44% of C10:0 was kindly provided by Stepan (The Netherlands) and was used without further purification. Tween 20 and sodium dodecyl sulphate (SDS) were purchased from Sigma-Aldrich (St. Louis, MO, USA) and dodecyltrimethylammonium bromide (DTAB) was acquired from Acros Organics (Geel, Belgium). Milli-Q water (Milli-Q apparatus, Millipore Corp., Bedford, MA, USA) was used to prepare all solutions.
2.2. Experimental procedures 2.2.1. Preparation of non-ionic, cationic and anionic nanoemulsions by high-pressure homogenization Oil-in-water (O/W) emulsions were prepared according to (Pinheiro et al., 2013) with some modifications. Briefly, the nanoemulsions were pre-mixed during 2 min at 5000 rpm using an Ultra-Turrax homogenizer (T 25, Ika-Werke, Germany) followed by passage through a high-pressure homogenizer (Nano DeBEE, BEE International, USA) according to the fractional factorial design (Table 1). To assess the effect of operational conditions on emulsion stability at the nanoscale, samples were evaluated during a 28, 35 and 365 days of storage. The stability at day 365 was only performed for the nanoemulsions with the best stability results at day 35. The prepared emulsions were stored at 4 °C in the absence of light, during the evaluation period.
2.2. Experimental procedures 2.2.1. Preparation of non-ionic, cationic and anionic nanoemulsions by high-pressure homogenization Oil-in-water (O/W) emulsions were prepared according to (Pinheiro et al., 2013) with some modifications. Briefly, the nanoemulsions were pre-mixed during 2 min at 5000 rpm using an Ultra-Turrax homogenizer (T 25, Ika-Werke, Germany) followed by passage through a high-pressure homogenizer (Nano DeBEE, BEE International, USA) according to the fractional factorial design (Table 1). To assess the effect of operational conditions on emulsion stability at the nanoscale, samples were evaluated during a 28, 35 and 365 days of storage. The stability at day 365 was only performed for the nanoemulsions with the best stability results at day 35. The prepared emulsions were stored at 4 °C in the absence of light, during the evaluation period.