Coaxial electrospraying of biopolymers as a strategy to improve protection of bioactive food ingredients

Laura G. Gómez-Mascaraque, Fran Tordera, Maria Jose Fabra, Marta Martínez-Sanz, Amparo Lopez-Rubio

Index: 10.1016/j.ifset.2018.03.023

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Abstract

Coaxial electrospraying is a promising technique for the production of multilayer encapsulation structures whose potential has already been demonstrated for pharmaceutical and biomedical applications. The aim of this work was to extend its application to the food sector by developing novel coaxially electrosprayed microcapsules using all food-grade materials. For this purpose, zein and gelatin were used as shell biopolymers to microencapsulate two model bioactive ingredients, i.e. epigallocatechin gallate (EGCG) as a model hydrophilic compound and α-linolenic acid (ALA) as a model hydrophobic molecule. The performance of the coaxially-obtained particles in terms of protection was evaluated in comparison with that of uniaxially electrosprayed materials. Particle sizes varied with composition and encapsulation efficiency (EE) was dependent on the chemical affinity between the shell matrix and the bioactive compound, but in general, greater EE was obtained in the coaxial systems. Moreover, enhanced bioactive protection ability was demonstrated by the coaxial structures, as observed in thermal degradation assays (for ALA) and antioxidant activity after in-vitro digestion (for EGCG). Industrial relevance This work emphasizes the usefulness of the electrospraying technique for the production of encapsulation structures for bioactive protection using all food-grade materials, without the need of applying high temperatures and generating small capsule sizes (in the submicron range). It also demonstrates that the coaxial configuration may be used to design encapsulation systems with enhanced protection ability for both hydrophilic and hydrophobic bioactive compounds.