Simple and complex coacervation methods for the nanoencapsulation of Rosa damascena mill L. anthocyanin in zein/potato starch: A new approach to enhance antioxidant and thermal properties.

Abstract

The structure and antioxidant properties of zein and potato starches as well as the stability of anthocyanins strongly depend on the pH. However, due to the stability of anthocyanins in at acidic medium, their encapsulation has been limited to low pHs. In the present work, an encapsulation of anthocyanins extracted from Rosa damascena mill L. (as a model) into zein, starch, and their binary mixtures by simple and complex coacervation methods over a wide range of pH (especially higher pHs), and different encapsulating agent doses and different initial volumes of anthocyanin were studied in order to obtain new conditions for the preservation of anthocyanins and to improve the antioxidant activities of zein and potato starches. High levels of antioxidant activity and encapsulation efficiency for zein/starch/anthocyanin nanocapsules and maximum antioxidant activity for zein/starch nanocapsules (without anthocyanin) were obtained at pHs 8 and 2, respectively. Fourier transform infrared spectroscopy, field emission scanning electron microscopy, X-ray powder diffraction, and thermal gravimetric analysis techniques were used to analyze simple and complex coacervates biopolymer interactions, morphology, and thermal stability. The size of zein nanocapsules (283-366nm) decreased in the range of 50-175nm after the encapsulation of anthocyanin (pH 8), which makes them suitable for drug delivery processes. The prepared nanocapsules showed a high scavenging ability.