Creating an emulsion using food-grade edible oils, researchers from University of Bordeaux 1 and France's INRA report that the mineral can be encapsulated and used to fortify dairy products.
"Due to a change in the nutrition habits, the daily intake in magnesium is lower than the recommended value.
For example, studies revealed that about 20 per cent of the French population present a magnesium deficiency," explained the authors in the journal Food Hydrocolloids .
"Magnesium addition in foods can induce chemical degradations, protein aggregation and generate an unpleasant taste," they added.
"These drawbacks could be avoided or at least decreased by encapsulation."
The new research taps into growing interest in the development of water-in-oil-in-water (W/O/W) emulsions.
Current application of the technique is limited due to difficulties with the stability of the internal water droplets.
This is linked to thermodynamic stability issues, and their strong tendency for droplet coalescence.
However, by carefully selected the appropriate oil, the researchers report that the release of magnesium can be controlled and applicable to dairy, and may overcome some of the problems currently limiting the fortification of certain foods with magnesium.
The researchers, led by Maud Cansell, formulated W/O/W emulsions using rapeseed oil, olive oil, olein, and/or miglyol.
Polyglycerol polyricinoleate and sodium caseinate were employed as emulsifiers, with magnesium encapsulated in the inner water droplets.
Cansell and co-workers report that both the initial water-in-oil, and subsequent W/O/W emulsion showed good stability.
Leakage of the mineral was affected by the choice of oil used, they state, with greater leakage observed for oils with lower viscosity and a higher proportion of saturated fatty acids.
Moreover, the W/O/W emulsions were stable after various thermal treatments mimicking the pasteurisation processes, they added.
"Thus, the W/O/W emulsions could be exploited for the supplementation of dairy products.
At last, the fact that pancreatic lipase was able to hydrolyze the oil lipids suggested that magnesium could be available at the intestinal site," concluded the authors.
Deficient levels of magnesium have been linked to a range of clinical disorders including high blood pressure (hypertension) and cardiovascular diseases, muscular weakness, and diarrhoea.
Source: Food Hydrocolloids (Elsevier) Published on-line ahead of print 5 December 2007, doi:10.1016/j.foodhyd.2007.11.016 "Release rate profiles of magnesium from multiple W/O/W emulsions" Authors: M. Bonnet, M. Cansell, A. Berkaoui, M.H. Ropers, M. Anton and F. Leal-Calderon