Submitted to: Journal of Food Science and Technology
Publication Type: Proceedings
Publication Acceptance Date: 11/13/2008
Publication Date: 11/27/2008
Citation: Mikkonen, K., Tenkanen, M., Cooke, P.H., Xu, C., Hannu, R., Willfor, S., Holmbom, B., Hicks, K.B., Yadav, M.P. 2008. Mannans as stabilizers of oil-in-water beverage emulsions. Journal of Food Science and Technology. 42:849-855.
Technical Abstract: Plant polysaccharides and gums such as gum arabic (GA) are commonly used as stabilizers of oil-in-water emulsions. O-acetyl-galactoglucomannan (GGM), a by-product from mechanical pulping of spruce wood, is able to stabilize colloidal wood resin emulsions (Hannuksela and Holmbom, 2004), but its use as emulsifier in food applications has not been studied previously. The effect of the chemical structure of mannans on their emulsion stabilizing capacity is not well known. The purpose of this study was to evaluate the utilization of GGM as emulsifier of beverage flavor, to examine the relationship between the chemical structure of galactomannans and their emulsification properties and to compare the emulsion stabilizing capacity of different mannans to that of the well known emulsifier GA and its novel challenger corn fiber gum (CFG) (Yadav et al., 2007). A decrease in the degree of polymerization of galactomannans decreased emulsion stability (turbidity). However, emulsions from GGMs, which have a relatively low degree of polymerization, had high turbidity. Emulsions from ethanol precipitated GGM (GGMEtOH) were almost as stable as those from GA. Konjac glucomannan (KGM) and locust bean gum (LBG)-based emulsions had a low turbidity. The effect of the number of galactose side groups on the stability of mannan emulsions did not show a clear trend. At room temperature, CFG was a slightly better emulsifier than GGMs, but at 4 degrees C the turbidities of emulsions from CFG and GGMEtOH were at the same level. Increasing the storage temperature to 45 degrees C caused a rapid breakage of emulsions from GGMs, CFG and unmodified GG. The average particle size of oil droplets in GGM emulsions stayed small (<1 mu m) during the observation time (14 days). No difference could be seen between the particle size of oil droplets in emulsions from GGMEtOH and spray-dried GGM (GGMSpDr). Although the effect of the chemical structure of mannans on emulsion stability is complex, GGM seems to be a promising material for oil-in-water emulsion stabilization.