Pectin coats can help produce eco-friendly stable oil emulsions

A new study has suggested that a cross-linked pectin coat could improve the stability of natural oil bodies, making their industrial use more viable.

The research, published in the Journal of Agricultural and Food Chemistry, suggests that using an enzyme to bind a coating layer onto natural oil bodies could increase their stability and give a more natural, environmentally-friendly way to produce oil emulsions.

“Oil bodies can be isolated from soybeans … and can therefore be used in products where emulsified oil would normally be used,” wrote the researchers, led by Professor Eric Decker from the University of Massachusetts; however, extracting them can be challenging as they are notoriously unstable.

Prof Decker told CosmeticsDesign-Europe.com’s sister site FoodNavigator.com that the commercial applications of this technique are “vast and range from uses in creams and oils for the cosmetics industry, right through to uses in functional foods.”

The new study is part of an “ongoing project to make this a commercially viable technique”, he said, and pointed out that the oil bodies produced are more environmentally friendly than chemically extracted oils, and that the method was more “natural and sustainable”.

Chemical extraction

Currently the overriding method of extracting oils from seeds and grains is to chemically separate them using hexane.

The potential for the use of oil bodies – tiny emulsion drops found in seeds and grains – has been seen as a possible replacement for chemically extracted oils. However, their instability means they are not currently viable for use.

“Oil bodies are natural emulsions, so there is no need to chemically mix them. The question is how to get them out and keep them stable enough for use” said Professor Eric Decker, one of the collaborators on the new study.

The purpose of the new study was to asses the potential use of laccase enzymes to add stability to extracted oil bodies by cross-linking a pectin coating.

Increased stability

The study found that the use of laccase enzymes to covalently cross-link beet pectin molecules “greatly increases stability”.

The research also observed that a cross-linked pectin layer provided additional stability to the oil bodies at acidic pH values, where non-cross-linked pectin layers became detached and unstable.

Industry potential

The new study offers potential for a more natural way to use oil emulsions for industry. But, despite its environmental benefits, Decker said that it could be a while until the new technique is widely used:

The biggest barrier to us now is economics; chemically extracted oils are cheaper than the method we use so we need to find benefits that would increase the value of the technique and justify the extra expense” he said.

Prof Decker added that the process had “immediate niche market applications, with uses in the production of higher value, top end, ‘natural’ and ‘organic’ products.”

Source: Journal of Agricultural and Food Chemistry

Published online ahead of print, doi: 10.1021/jf102082u

“Stabilization of Soybean Oil Bodies by Enzyme (Laccase) Cross-Linking of Adsorbed Beet Pectin Coatings”

Authors: B. Chen, D.J. McClements, D.A. Gray, E.A. Decker.