Colour-protein mix gives glimpse of functional emulsions future
According to findings published in Food Research International, bovine serum albumin (BSA) and carotenoids like beta-carotene and astaxanthin can form complexes, which can then be used as the surface active substance (SAS) for an oil-in-water emulsion.
“Since BSA is an affordable resource and the colour of a product influences the consumer purchase decision, this approach might stimulate the food industry in producing such emulsion-based products,” wrote the researchers, led by Hainer Wackerbarth from Laser-Laboratorium Gottingen.
Functional foods are emerging as a segment of the market with increasing economic importance, noted the researchers. Indeed, Datamonitor valued the European functional foods market at US$0.8bn in 2006. The US, meanwhile, which has a population of around 301m compared to the EU's 490m (from January 1, 2007), was valued at $21.3bn.
“Another aspect of the study concerns the health beneficial impact of carotenoids,” they added. “Since carotenoids are poorly absorbed from unprocessed food, this kind of functional oil-in-water emulsions may have the potential for increasing the intake of carotenoids in particular compared to encapsulated products.”
The German and Australian researchers also note that, beside the potential health benefits of carotenoids, they are also used extensively as food colours.
“Since the consumer purchase decision of food is, inter alia, based on the colour, the market position of a product can be improved, in particular by application of natural pigments in contrast to synthetic colourant, since there is an increased demand for natural mild processed food,” they said.
Replacing solvents
The researchers prepared the BSA-carotenoid complexes by first dissolving astaxanthin or beta-carotene in pure ethanol, and mixing with the albumin. The emulsion was prepared by mixing this with a neutral oil.
This approach, described by the researchers as “novel” allowed the production of a emulsion without using any undesirable organic solvents.
Confocal laser scanning spectroscopy showed that the carotene cream phase consists of densely packed droplets with minimal coalescence of the droplets.
Furthermore, they note that the astaxanthin and beta-carotene-containing emulsions remained stable for “at least for 18 days and 5 days, respectively”.
“The present study has described the preparation of an astaxanthin and beta-carotene-enriched emulsion without applying undesired organic solvents or carotene modifying conditions (e.g. elevated temperature),” said the researchers.
“There is a consumer demand for natural mild processed food, which can be matched by this approach,” they added.
Wackerbarth collaborated with scientists from Proteomics International in Australia, and the German Institute of Food Technology. The study was funded by the State of Lower Saxony.
Source: Food Research International
Published online ahead of print, doi: 10.1016/j.foodres.2009.04.002
“Carotenoid-protein interaction as an approach for the formulation of functional food emulsions”
Authors: H. Wackerbarth, T. Stoll, S. Gebken, C. Pelters, U. Bindrich
