Abstract
Olive oil-in-bitter orange juice (O/W) nano-emulsions were prepared by Phase Inversion Composition method. Binary combinations of Tween80, Span20, sucrose monopalmitate and sunflower lecithin were used as surfactants. Influence of type (locust bean gum, xanthan gum, iota-carrageenan) and concentration (0–0.40%) of added hydrocolloid upon physical (visual appearance, transparency (T), microstructure, particle size (D43)) and rheological properties (consistency index (K), flow index (n), apparent viscosity (Ƞa) of nano-emulsions were investigated. The lowest D43 (0.143 µm–0.569 µm) and Ƞa (2.46–2.51 cp) accompanied with the highest T (47.50–70.65%) were observed in nano-emulsions prepared without hydrocolloid. Significant negative correlation was found between D43, Ƞa and T, i.e., hydrocolloid addition increased the Ƞa and D43, as well as T loss. The Power Law model was well-suited to the experimental data (R2>0.9534). The n values of Tween80/Span20, Tween80/SL and Tween80/SMP nano-emulsions in the absence of hydrocolloid were 1.00, 0.98 and 0.99, respectively, which presents a Newtonian behavior. The n values of Tween80/Span20, Tween80/SL and Tween80/SMP nano-emulsions in the presence of LBG, XA and i-CARR at varying concentrations were in the range of 0.16–0.99, 0.13–0.98 and 0.15–0.97, respectively, which presents Non-Newtonian shear-thinning behavior. Same type of hydrocolloid showed similar trend in all nano-emulsions regardless of emulsion composition. There has been significant positive correlation between D43, K and Ƞa, while there has been significant negative correlation between T, n and Ƞa.
Acknowledgements
The study was carried out with the existing infrastructure of the food engineering department of Gaziantep University without any fund.
Disclosure statement
The authors declare that they have no conflict of interest.