Encapsulation of rose essential oil using whey protein concentrate-pectin nanocomplexes: Optimization of the effective parameters

• Rose essential oil was loaded into whey protein concentrate-pectin nanocomplexes. • Encapsulation efficiency = 96.97% at 4:0.5 ratio of whey protein concentrate to pectin. • Formation of the strongest complex was achieved at the pH value of 3. • The highest porosity and solubility of 0.912 and 52%, respectively, achieved at pH = 9. The aim of this study was to optimize the preparation of whey protein concentrate (WPC)-pectin nanocomplexes as a carrier for rose essential oil (REO) via response surface methodology (RSM); with initial concentrations of WPC (4–8%) and pectin (0.5–1%) at different pH values ​​(3–9). The highest encapsulation efficiency of REO was 96.97% for 4.0:0.5 ratio of WPC:pectin at pH = 3. The highest viscosity was obtained at 4:1 ratio of WPC:pectin and pH = 3, and the highest stability (96.5%) was related to 4:1 ratio of WPC:pectin at pH = 9; the lowest stability (81%) was observed at 4:1 ratio of WPC:pectin at pH = 3. Finally, the highest solubility occurred at pH = 9 while the lowest solubility was seen in the treatments prepared at pH = 3 due to the creation of a strong WPC-pectin coacervate complex.