Galactoglucomannan (GGM) from spruce were more effective for stabilising beverage emulsions than guar gum, Konjac glucomannan, and locust bean gum, according to results published in the journal LWT - Food Science and Technology.
“This study is the first indication of the potential of GGM as a stabilizer of food emulsions and shows that GGM is an interesting option for an emulsion stabiliser to be studied further in future,” wrote lead author Kirsi Mikkonen from the University of Helsinki.
Galactomannans, like guar gum, are commercially important for the food industry and are extensively used as stabilizers, thickeners, emulsifiers and gelling agents.
The research, performed in collaboration with scientists from the USDA’s Agricultural Research Service (ARS) and Finland’s Abo Akademi University, builds on earlier studies from the two Finnish universities published in Carbohydrate Polymers (May 2008, Vol. 72, pp. 197-210).
When FoodNavigator reported on this earlier study in 2007, Professor Stefan Willfor from Abo Akademi University told this website that, according to computerised/ theoretical upscaling calculations from Sweden (Persson et al., Appl. Biochem. Biotechnol. 2007) for GGM production for the packaging industry, prices of less than $700 per ton GGM were suggested, “which is quite reasonable", he said.
Mikkonen, a doctoral student at the Department of Food Technology, told this website that these figures are the best reference of price that currently exists.
The new study investigated the stabilising effect of spruce GGM on emulsions in model beverages, and compared the results to guar gum and locust bean gum galactomannans, konjac glucomannan, and corn arabinoxylan.
Mikkonen and her co-workers report that the GGM increased the cloudiness (turbidity) of emulsions both immediately and after 14 days of storage at room temperature. Furthermore, the GGM emulsions had higher cloudiness than the emulsions containing other mannans.
In terms of stability, the researchers report that GGM was more effective as an emulsion stabiliser than both guar gum and locust bean gum.
“A beverage emulsion is a complex system in which many factors, such as molar mass, branching, concentration, viscosity, and dilution of the stabilizing hydrocolloid have a profound effect on emulsion stability. Thus, despite the similarities in the sugar composition of GGM and other mannans, they differed significantly in emulsifying performance,” wrote the researchers.
A microscopy study showed that the GGM particles measured less than one micrometre in diameter.
In an email correspondence, Mikkonen cautioned that the research of GGM emulsions is in an early stage and that industry has not been involved to date.
“We are currently studying the formation of edible films from GGM, but in future we are interested in new projects also on the emulsification properties of GGM,” she said.
The study was funded by the Foundation for Research of Natural Resources in Finland, the Finnish Funding Agency for Technology and Innovation (Tekes), and the Academy of Finland.
Source: LWT - Food Science and TechnologyVolume 42, Issue 4, Pages 849-855“Mannans as stabilizers of oil-in-water beverage emulsions”Authors: K.S. Mikkonen, M. Tenkanen, P. Cooke, C. Xu, H. Rita, S. Willfor, B. Holmbom, K.B. Hicks, M.P. Yadav