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.

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 (283-366 nm) decreased in the range of 50-175 nm after the encapsulation of anthocyanin (pH 8), which makes them suitable for drug delivery processes. The prepared nanocapsules showed a high scavenging ability.

Introducing potato starch-ecofriendly silver nanoparticles as a novel binary system for nanoencapsulation of riboflavin.

Riboflavin (Rf), an externally supplied nutrient, is highly photosensitive, and should be protected from sunlight once used in food and pharmaceutical manufacturing. The applications of encapsulated Rf have recently developed due to their therapeutic properties. In this study, the use of green silver nanoparticles (AgNPs) synthesized by Rosa damascena mill L. extract to control the encapsulation efficiency of Rf in potato starch was demonstrated for the first time. Starch/Rf, Starch/AgNPs/Rf and Starch/AgNPs nanocapsules were characterized by Fourier-transform infrared, field emission scanning electron microscopy, differential scanning calorimetry, and brunauer-Emmett-Teller techniques. The obtained results showed that the presence of AgNPs reduces Rf nanocapsules size (from 340 to 327 nm), increases the encapsulation efficiency (21.14 ± 0.62 to 92.52 ± 1.32 %) and improves the thermal stability, antibacterial and antioxidant activities. Moreover, UV-vis spectroscopy demonstrated the stronger association of AgNPs/Rf and AgNPs/Rf/Starch nanocapsules with BSA under physiological conditions.