Production of pectin-whey protein nano-complexes as carriers of orange peel oil

Orange peel oil is one of the most common flavorings used in the food industry which is volatile under environmental conditions. Encapsulation is the best way to protect it and control its release. One of the nanoencapsulation systems for food bioactive ingredients is complexation method, which entraps the core materials in a complex of two different biopolymers. In this study, orange peel oil was nanoencapsulated by pectin-whey protein nanocomplexes. After determining the optimum nanocomplex suspensions containing orange peel oil based on the stability, viscosity, and color, they were formulated in three different pH values (3, 6 and 9) and converted into powdered forms by freeze drying. The analysis of size and zeta potential of nanocomplexes revealed that the smallest particles formed in pH = 6. The encapsulation efficiency of the powders at pH = 3, 6 and 9 were 88, 84, and 70%, respectively and there was a reverse linear correlation between encapsulation efficiency and the color index (b*). The microstructure and the morphology of the nanocomplex powders was investigated by SEM and AFM and the results showed that more spherical particles are formed in pH = 3. FTIR analysis determined that there was a chemical reaction and bond formation between whey proteins and pectin as a sharp band was appeared in 991 cm−1.