Nanoencapsulation of D-limonene within nanocarriers produced by pectin-whey protein complexes

D-limonene as a volatile compound is widely used in the food flavorings and it is chemically unstable in the presence of air, light, moisture, and high temperatures. Biopolymer nanocomplex formation between negatively charged polysaccharides and positive proteins is a novel encapsulation technology for protecting of bioactive components. In this study, D-limonene was nanoencapsulated with whey proteins (4, 6 and 8% w/w), and pectin (0.5, 0.75 and 1% w/w) at different pH values (3, 6 and 9). Our results revealed that nanocomplexes prepared with 4% WPC and 1% pectin in pH = 3 had the lowest stability and highest viscosity as well as the highest L* which was selected as the optimum treatment. Atomic force microscopy images showed the morphology of these WPC-pectin nanocomplexes as spherical nanoparticles with an average size of 100 nm. The encapsulation efficiency was determined to approximately 88%. Results of dynamic light scattering for produced nanocomplexes loaded with D-limonene revealed a particle size of about 160 nm and a zeta potential of -0.53 mV. It was found that a ratio of 4 to 1 between WPC and pectin came up with the highest complex formation. (C) 2017 Elsevier Ltd. All rights reserved.