Microencapsulated lycopene may stabilise colour properties: Study
The new study, published in the Journal of Food Process Engineering, evaluates the colouring stability of free lycopene in comparison with a microencapsulated lycopene, using the pre-extrusion colouring of a rice flour extrudate as a model for testing stability.
The authors found that microencapsulation was found to have better colour retention when used in the extrusion model, and also led to a twofold increase in storage stability.
“Lycopene microcapsules as pre-extrusion colouring … were reported to be much more stable than free lycopene, under all the conditions of extrusion processing,” said the researchers, led by first author Sheetal Choudhari from the University of Mumbai Matunga, India.
“This suggests that microencapsulated lycopene is more stable under the extrusion processing as well as during storage,” they said.
Colour capsules
Natural colours are a diverse group of colorants, with a wide range of solubility and stability properties.
Choudhari and colleagues said that lycopene is one of the nutritionally important carotenoids, and its presence in the diet may reduce the risk of cardiovascular disease, cancer and other diseases associated with aging.
They noted that in addition to its potential nutraceutical properties, lycopene is also a natural colouring, giving it a “dual advantage in processed foods”.
However, lycopene has poor stability, which currently precludes it from many of its possible applications in food formulations.
“Microencapsulation aims to totally entrap the pigment particles in a protective network, which isolates and stabilizes the pigment,” explained Choudhari and co- workers.
Previous research by has suggested that the stability of lycopene could be improved via a spray drying microencapsulation process
“In our earlier work, we developed a technique for microencapsulation of lycopene … the microcapsules had a sevenfold increase in its stability,” said the studies authors.
The new research evaluated the stability of the microencapsulated lycopene compared to free lycopene, for the pre-extrusion colouring of a rice flour extrudate
Study details
The effect of extrusion conditions on the retention of lycopene during extrusion of rice flour was chosen as a model to test the stability of lycopene. The experiments were carried out by extrusion of rice flour containing 1 per cent lycopene microcapsules or free lycopene equivalent to that in the microcapsules.
The authors reported that the microencapsulated lycopene gave better retention of colour in the extrudates than the free lycopene in all tests of stability, and under all extrusion conditions tested.
Storage stability of the microencapsulated lycopene was also observed to increase twofold compared to free lycopene over a period of 96 hours.
Choudhari and colleagues said the colour retention in the pre-extrudates may be further improved through the use of appropriate packaging, and the use of optimum processing conditions, however this requires further investigation.
Source: Journal of Food Process Engineering
Published online ahead of print, doi: 10.1111/j.1745-4530.2010.00562.x
“Microencapsulated lycopene for pre-extrusion coloring of foods”
Authors: S. Choudhari, I. Bajaj, R. Singhal, M. Karwe
