Pectin coats could provide eco-friendly oils
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, e.g., beverages, sauces, dips, deserts, and dressings,” wrote the researchers, led by Professor Eric Decker from the University of Massachusetts.
Prof Decker told FoodNavigator that the commercial applications of this technique are “vast and range from uses in crèmes 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”.
Currently the only way to extract 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, oil bodies are notoriously unstable using current extraction methods, meaning they are not currently viable for use in food products.
Research has focused on finding a way to produce natural emulsions using stable oil bodies.
“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 – a follow up to a 2008 study - was to asses the potential use of laccase enzymes to add stability to extracted oil bodies by cross-linking a pectin coating.
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.
The study confirmed that uncoated oil bodies were relatively stable to salt and freeze-thaw cycling at pH 7, saying that in these cases, a beet pectin coating led to no further improvement in stability, and actually decreased their stability in some cases.
The new study offers potential for a more natural way to use oil emulsions for industry. Despite its environmental benefits, Decker told this website that it could be a while until the new technique is widely used by the food industry:
“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.”
“Natural, and organic products are important to consumers. There is no current way to extract natural oil bodies for use in these products” he said.
With the higher cost of production, and potentially lucrative applications in higher end products, the short-term viability for use in large scale industrial applications is small: “It’s certainly not going to be used to make mayo any time soon” added Decker
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.