Electrosprayed Agar Nanocapsules as Edible Carriers of Bioactive Compounds

Abstract

Electrosprayed agar nanocapsules were developed using an acetic acid solution as solvent. The role of solution properties (viscosity, surface tension, and conductivity) in the formation of agar particles was assessed, together with the effect of both agar and acetic acid concentrations on the size and morphology of the resulting particles. Agar solutions with a concentration below 10% w/v were not suitable for electrospraying. Furthermore, the agar–acetic acid ratio was also critical for the formation of agar nanostructures (with an optimum ratio of 1:2). A decrease in particle size was also observed when decreasing agar concentration, with particle diameter values ranging between 50 and 400 nm. Moreover, the suitability of the electrosprayed agar nanocapsules as carriers for a model bioactive compound, chlorophyllin sodium copper salt (CHL), was also evaluated. The release profile of encapsulated CHL, with an estimated encapsulation efficiency of around 40%, was carried out in food simulants with different hydrophilicity (10% v/v and 50% v/v ethanol). While the release of the bioactive was negligible in the hydrophilic food simulant, an initial burst release followed by a slower sustained release was observed when the capsules were immersed in 50% ethanol solution. The results open up a broad range of possibilities that deserve further exploration related to the use of these edible polysaccharide-based nanocapsules.

Recent Advances in Encapsulation for Food Applications

“…The last paper published in this Special Issue focused on a different encapsulation technique to develop micro-or nanostructures for the delivery of active compoundselectrohydrodynamic processing (EHD) [23]. The EHD technique includes two variations: electrospinning and electrospraying.…”

“…In these processing technologies, a polymer solution can either be spun or sprayed through the application of an external electric field, giving rise to fibers or particles, respectively. In this manuscript, Tomadoni et al prepared electrosprayed agar nanocapsules as edible carriers of a model bioactive compound (chlorophyllin sodium copper salt) [23]. These nanocapsules were developed using an acetic acid solution as a solvent, and the role of the solution's properties in the formation of agar particles was evaluated in terms of capsule size, morphology and encapsulation efficiency.…”

“…The release profile of the chlorophyllin sodium copper salt was studied using two food simulants with different hydrophilicity (10% v/v and 50% v/v ethanol). The authors concluded that the release of the bioactive compound was negligible in the hydrophilic food simulant, while an initial intense release followed by a slower, sustained release was observed when the capsules were immersed in 50% ethanol solution [23].…”