Writing in the journal Food Hydrocolloids , scientists, from the Mie Prefectural Science and Technology Promotion Centre and Kyoto University, report that the hydrocolloid from leaves of Corchorus olitorius (HLC) exhibited strong synergistic effects with the established hydrocolloid kappa-carrageenan.
"The synergistic effect on mixed gel made with kappa-carrageenan was different from mixed gels with locust bean gum (LBG) in the following respect; in the case of addition of HLC, the maximum synergistic effect was observed at the sugar composition (kappa-carrageenan/HLC) of 90/10 while that of kappa-carrageenan/LBG were observed around 60/40 to 50/50," wrote lead author Eiji Yamazaki.
"The difference implies that HLC could not only be an alternative to LBG in many applications, but may introduce new functions to kappa-carrageenan and other hydrocolloids."
Hydrocolloids are used extensively by the food industry to texturise and stabilise food products from dressings to ice cream.
Though these products are sensitive to spiralling raw material costs, the demand for hydrocolloids remains impressive.
The researchers extracted the polysaccharise from dried leaves of Corchorus olitorius using a 50 per cent concentration ammonium sulphate solution, followed by precipitation in water, and extraction to yield HLC.
Mixed gels were prepared at concentrations of one per cent using kappa-carrageenan and HLC or LBG - kappa-carrageenan forms a gel on cooling, while LBG does not form a gel by itself.
"Comparing to LBG, HLC would be expected to give synergy with kappa-carrageenan at rather smaller amounts," wrote Yamazaki.
"Hence the utilisation of HLC to kappa-carrageenan for milk desserts would be of advantage against LBG.
In order to understand the mechanism of the synergistic effect between kappa-carrageenan and HLC, structural feature of HLC, interaction of HLC with kappa-carrageenan, and microstructure of the mixed gel with be further studied," he added.
"Thus Corchorus olitorius is an interesting source of hydrocolloid though further investigation should be done in order to fully explore the potential of HLC," concluded Yamazaki.
Historically, the use of carrageenan for food has grown in industrialised countries by at least 5 to 7 per cent per year, particularly on the back of growing demand for convenience foods.
In the EU the food market has grown to use both refined known as E407 on food labels- and semi-refined (E407a) carrageenan.
In the US, there is no distinction for the food labels the hydrocolloid is simply known as carrageenan.
Source: Food Hydrocolloids (Elseveier) Published on-line ahead of print, doi: 10.1016/j.foodhyd.2007.03.009 "Hydrocolloid from leaves of Corchorus olitorius and its synergistic effect on kappa-carrageenan gel strength" Authors: E. Yamazaki, O. Kurita, Y. Matsumura