Rocío Pérez-Masiá

Encapsulation of folic acid in food hydrocolloids through nanospray drying and electrospraying for nutraceutical applications

In this work, two different technologies (electrospraying and nanospray drying) were evaluated for the encapsulation of folic acid using both a whey protein concentrate (WPC) matrix and a commercial resistant starch. The morphology of the capsules, molecular organization of the matrices upon encapsulation, encapsulation efficiency, and stability of the folic acid within the capsules under different storage conditions and upon thermal exposure were studied. Results showed that spherical nano-, submicro- and microcapsules were obtained through both techniques, although electrospraying led to smaller capsule sizes and to an enhanced control over their size distribution. Greater encapsulation efficiency was observed using WPC as encapsulating matrix, probably related to interactions between the protein and folic acid which favoured the incorporation of the bioactive. The best results in terms of bioactive stabilization in the different conditions assayed were also obtained for the WPC capsules, although both materials and encapsulation techniques led to improved folic acid stability, especially under dry conditions.

Surfactant-aided electrospraying of low molecular weight carbohydrate polymers from aqueous solutions.

In this work it is demonstrated, for the first time, that it is feasible to develop, using the electrospraying technique, low molecular weight carbohydrate-based capsule morphologies from aqueous solutions through the rational use of surfactants. Two different low molecular weight carbohydrate polymers were used, a maltodextrin and a commercial resistant starch. The solution properties and subsequent high voltage sprayability was evaluated upon addition of non-ionic (Tween20, and Span20) and zwitterionic (lecithin) surfactants. The morphology and molecular organization of the structures obtained was characterized and related to the solution properties. Results showed that, while unstable jetting and dropping occurred from the pure carbohydrate solutions without surfactant, the addition of some surface active molecules above their critical micelle concentration facilitated capsule formation. Higher surfactant concentrations led to smaller and more homogeneous capsule morphologies, related to lower surface tension and higher conductivity of the solutions.

Development and Optimization of Novel Encapsulation Structures of Interest in Functional Foods Through Electrospraying

The aim of this work was to establish strategies for the development of electrosprayed encapsulation structures, of interest in food applications, based on aqueous hydrocolloid dispersions. Specifically, various polysaccharides and two different proteins were evaluated for capsule formation. To this aim, the hydrocolloid dispersion properties were analysed and compared with the solution properties of two polymers readily spinnable in water (polyvinyl alcohol (PVOH) and polyethylene oxide (PEO)). Increasing the hydrocolloid concentration to promote chain entanglements resulted in a valid strategy only for a few matrices (related to their greater Mw). As alternative strategies to improve the physical properties and, thus, the sprayability of the dispersions, addition of gums and surfactants to modify their viscosity and surface tension, respectively, was evaluated. Moreover, denaturation of proteins was also carried out in order to investigate the effect of this treatment on the electrospraying process and on capsule formation. Results showed that the incorporation of some of these molecules, as well as protein denaturation, significantly changed the physical properties, allowing the development of encapsulation structures from all the hydrocolloids assayed. The morphology of the structures obtained was characterized, and the molecular organization of some of the capsules was studied and related to the electrosprayability and capsules morphology.

Impact of Acetic Acid on the Survival of L. plantarum upon Microencapsulation by Coaxial Electrospraying

In this work, coaxial electrospraying was used for the first time to microencapsulate probiotic bacteria, specifically Lactobacillus plantarum, within edible protein particles with the aim of improving their resistance to in vitro digestion. The developed structures, based on an inner core of whey protein concentrate and an outer layer of gelatin, were obtained in the presence of acetic acid in the outer solution as a requirement for the electrospraying of gelatin. Despite the limited contact of the inner suspension and outer solution during electrospraying, the combination of the high voltage used during electrospraying with the presence of acetic acid was found to have a severe impact on the lactobacilli, not only decreasing initial viability but also negatively affecting the survival of the bacteria during storage and their resistance to different stress conditions, including simulated in vitro digestion.

Microencapsulation and Packaging—Value Added Solutions to Product Development

This chapter describes innovative technologies where protective encapsulation strategies have been described to generate innovation and novel function in the packaging area. In this respect, novel smart packaging with special focus on sensors and temperature buffers presents the leanest innovation where encapsulation plays a significant role from a technology implementation viewpoint. Additionally, innovative packaging strategies enclosing bioactives provide the packaging field with a new positive function for the consumer as a result of encapsulation of bioactives and their intended positive migration. Finally, more recent technologies making use of encapsulation are also presented to deliver brand recognition through aroma release and for the challenging printed electronics application. The high-throughput electrohydrodynamic processing tool appears as the most significant advance in this area to facilitate the development of the cited applications in the medium term.

Development by Electrohydrodynamic Processing of Heat Storage Materials for Multisectorial Applications

Phase change materials (PCM’s) are substances that undergo a phase transition at a specific temperature and, as a result, they are able to absorb and release the latent heat when isothermal conditions are altered. PCM’s could be used during transport or storage, for the protection of solid foods, beverages, pharmaceutical products, textile industry, blood derivatives, electronic circuits, cooked food, biomedical products and many others.