Scientists from Wageningen University in The Netherlands report that the microcapsules can be formed using alternating layers of ovalbumin fibrils and high methoxyl pectin for encapsulation of ingredients like the flavour limonene.
According to a report in Food Hydrocolloids, the process follows “standard operations that can easily be scaled up to industrial production”.
Moreover, the researchers used food-grade materials: The pectin was supplied by CP Kelco, and the ovalbumin by Sigma-Aldrich. The particles formed had a diameter of between 5 and 6 micrometres, with more layers of the pectin and ovalbumin increasing the particle size.
With the fear of commodification continuously looming, food manufacturers are turning to microencapsulation technologies as a way of achieving much-needed differentiation and enhancing product value. Many scientific studies have reported promising results for pectin to encapsulate a range of different ingredients.
Technical details
Researchers from Wageningen’s Physics and physical chemistry of foods group used a layer-by-layer technique to prepare capsules for an oil-in-water emulsion containing limonene as a model flavour.
Compared to fibrils made from whey protein isolates, the ovalbumin fibrils were found to be semi-flexible and bound to the emulsion droplets. The pectin then formed a layer on top, and the ovalbumin self-assembled another layer on top, and so on.
Microcapsules with up to eight layers were prepared and the release of limonene was measured. The strength of the shell was found to increase as the number of layers increased, said the researchers, and this translated into increasing release times for the limonene.
“Going from four layers to eight the maximum release time increases by about a factor 3,” wrote the researchers. “The maximum release time as a function of the number of layers is increasing steadily which show the release can be delayed even more by adding additional layers.
“These results prove that the release properties of the multi-layer capsules can be tuned by controlling the number of layers in the shell of the capsules.”
The researcher was funded by the European Commission as part of the "Controlled Release" project.
Source: Food Hydrocolloids
Published online ahead of print, doi: 10.1016/j.foodhyd.2010.06.008
“Encapsulation systems based on on ovalbumin fibrils and high methoxyl pectin”
Authors: K.N.P. Humblet-Hua, G. Scheltens, E. van der Linden, L.M.C. Sagis and Physics and physical chemistry of foods group