Combined technologies key to vitamin A for foods
According to a new review by researchers at New Zealand’s Massey University, techniques such as single and double emulsions, solid lipid nanoparticles (SLNs), liposomes, and even nanoparticles, may not hold the solution by themselves, but in combination may offer the greatest potential.
“It is uncommon to find ‘silver bullet’ solutions to food preservation problems; a combination of approaches such as the ‘hurdle technology’ concept is more often successful,” they wrote in the journal Trends in Food Science & Technology.
“In our opinion, the most promising advances in vitamin A protection in foods will come from consideration of the multifaceted nature of vitamin degradation and the potential to combine technologies in ways that take advantage of their individual strengths.”
Vitamin A deficiency (VAD) is a serious public health problem in more than 50 per cent of all countries, especially in Africa and South-East Asia, according to the World Health Organisation, and causes blindness in up to 500,000 children each year.
Programs to deliver supplements and fortified foods to those at risk have achieved much but fortification of foods generates formulation headaches because of the instability of the vitamin.
“Large losses of vitamin A activity can occur during processing, transportation and storage of fortified foods,” wrote the Massey University researchers.
“Adding vitamin A above the intended fortification level to compensate for losses is undesirable because of the potential for overdosing.”
Avenues open to food science
In a timely review of the science, Simon Loveday and Harjinder Singh consider the potential techniques available.
They note that microemulsions and multiple emulsions some promise for stabilizing water-soluble ingredients, and therefore deserver further study.
SLNs and liposomes also show promise, and evidence from the literature exists of their efficacy.
Loveday and Singh consider lipid cochleates - particles composed of stacked phospholipid bilayers and configured in a spiral – as they are known to be effective in pharmaceutical applications. “To date there have been no applications in foods probably because existing processes for making cochleates use toxic solvents,” they wrote.
Gaps in the knowledge
While research into encapsulation of the nutrient is evident in the literature, the scientists noted a lack of information regarding the entrapment efficiency of the technology.
“This is important because a significant proportion of vitamin A mixed with an encapsulant can remain free in solution or adsorbed on surfaces, where it will be exposed to conditions that catalyse oxidation and/or isomerisation.
“Without a knowledge of encapsulation efficiency it is impossible to evaluate true loading capacity, and therefore difficult to compare the effectiveness of different systems.
“It is not possible to evaluate the commercial potential of diverse technologies based on information in the academic literature because the costs of ingredients are never disclosed in articles,” they stated.
Team-work may be the answer
The key to successful vitamin E fortification of food may come about from a combined approach, wrote Loveday and Singh.
“Synergistic protective effects are seen when individual technologies are combined, such as incorporating antioxidants into emulsions or SLNs, and encapsulating cyclodextrins complexes inside liposomes,” they concluded.
Source: Trends in Food Science & TechnologyPublished online ahead of print, doi: 10.1016/j.tifs.2008.08.002“Recent advances in technologies for vitamin A protection in foods”Authors: S.M. Loveday, H. Singh
