Nanoscale fibres with an attraction to fats were used to encapsulate fat-soluble ingredients and act as novel carriers for ingredients such as flavours, antioxidants, antimicrobials, and other bioactives, according to findings published in the Journal of Food Science.
“The manufacture of solid matrix containing nanodroplets could be of substantial interest for manufacturers wishing to develop encapsulation system for lipophilic functional compounds such as lipid-soluble flavours, antimicrobials, antioxidants, and bioactives with tailored release kinetics,” report researchers from the University of Milan in Italy and the University of Hohenheim in Germany.
Despite using predominantly non-food grade ingredients, the researchers indicate that the ‘manufacturing principal’ used in this study could be transferred easily to “other water-soluble polymers that have previously been electrospun and that are food-grade such as chitosan, dextran and gelatin”.
Food manufacturers are increasingly turning to encapsulation technologies as a way of achieving much-needed differentiation and enhancing product value. Tapping into key and emerging consumer trends with innovative techniques is becoming increasingly important for food manufacturers.
While the majority of focus has been on microencapsulation, more and more research is looking at the potential of nanoencapsulation.
Electrospinning refers to a technique whereby fine fibres are drawn from a liquid using an electrical charge. In this study, the researchers applied the technique to polyvinyl alcohol (PVA) fibres to encapsulate hexadecane-in-water nanoemulsions.
The electrospun PVA-nanoemulsions complexes contained up to 1.5 per cent oil and 8 per cent PVA. A range of analytical techniques including scanning electron microscopy, differential scanning calorimetry, and UV-spectroscopy showed that the emulsion droplets were indeed incorporated into the fibres, and were present as individual droplets or larger clusters (aggregated flocs).
“By incorporating emulsion droplets, a large variety of lipophilic ingredients can be easily loaded into the fibres' hydrophilic polymer matrix,” said the researchers.
The electrospun nano fibres are still some way from commercialisation, however. An existing limitation of the current method is the use of an organic solvent: “This is of practical importance as to date the only way to include a lipophilic ingredient in a nanofibers is by dissolving the lipophilic ingredient and polymer in an organic solvent followed by electrospinning,” explained the researchers.
“However, use of an organic solvent is (a) not feasible if one wants to electrospin hydrophilic polymers, and (b) use of organic solvents is generally highly undesirable in the food industry,” they added.
Source: Journal of Food Science
Published online ahead of print, doi: 10.1111/j.1750-3841.2010.01680.x
“Electrospinning of Poly(vinyl alcohol) Nanofibers Loaded with Hexadecane Nanodroplets”
Authors: A. Arecchi, S. Mannino, and J. Weiss