"The complex of vanillin/beta-CD can be used as an additive in foods that the vanillin is normally added as flavour with the advantage of higher antioxidant activity," wrote lead author lead author Vaios Karathanos from Harokopio University in Athens.
Such research is important because protecting the compound from oxidation could lead to reductions in the amount formulators need to add to flavour foods. The price of vanillin has risen significantly during the last twelve months.
Encapsulation of vanillin is not new, said Karathanos and co-workers, with gum arabic and modified starches, such as oxidized starches prepared from corn and waxy amaranth starch, already used as encapsulating agents.
Microcapsules are tiny particles that contain an active agent or core material surrounded by a shell or coating, and are now increasingly being used in food ingredients preparation.
The researchers extended this by looking at the vanillin-encapsulating potential of beta-cyclodextrin, a chemically and physically stable polysaccharide produced by the enzymatic modification of starch. Some cyclodextins are already used as carriers for natural colours, flavours and vitamins, solubilisers of lipids, stabilisers of oil in water emulsions, or flavour or aroma modifiers in a variety of processed foods.
The new research, published in the journal Food Chemistry (Vol 101, pp. 652-658), indicates that beta-CD also has significant potential as an encapsulator of vanillin.
Synthetic vanillin is a cost effective alternative to natural vanilla. Global demand currently hovers around 16,000 tons a year. By comparison, total world demand for natural vanilla is about 40 metric tons.
The reason for this is that synthetic vanillin costs one-hundredth of the price of the natural product. It not only substitutes for vanilla, but also supplements adulterated vanilla extracts.
The researchers used the freeze-drying method to produce encapsulated vanillin. The vanillin was obtained from Sigma, and the beta-CD from Aldrich Chemie. The vanillin was dispersed in a beta-CD solution with a molecular ration of one to one (1:1).
Techniques such as differential scanning calorimetry (DSC) and nuclear magnetic resonance (NMR) showed that the vanillin was protected against oxidation when encapsulated with beta-CD, even under conditions where free vanillin is oxidised (210 degrees Celsius).
"The vanillin molecule is all inside, the aldehyde group exits the primary side and the CHOOH axis must be tilted with respect to the cavity axis in order to accommodate the entire molecule inside," said the researchers.
"Encapsulation of vanillin in beta-cyclodextrin makes the active compound more soluble in water than the free molecule. Moreover, it may be concluded that the molecule of vanillin inside the cyclodextrin cavity is protected from oxidation, as depicted from oxidative DSC studies," they concluded.
The flavour arm of the French chemical giant, Rhodia, recently announced that increasing prices across its vanillin and ethylvanillin range by 6 per cent.
The firm argued that, as the global vanillin and ethylvanillin leader, it needed to guarantee capacity in order to be to invest in the future.
The hike also came as a direct response to current energy prices. There have been strong increases in both oil and gas prices, and the raw materials used in the production of vanillin are all high energy users.
But undercutting both these concerns is the issue of China. With vanillin growth in the mature markets of Europe and the US, annual growth is stable at around 2 per cent. But in China, this growth is set at over 10 per cent.
The second point is that vanillin is in short supply. This has created a situation whereby prices have been increased repeatedly.