Hydrocolloids go head-to-head as emulsifiers
for stabilising emulsions, researchers from Japan and the UK have
reported.
The study, published in the journal Food Hydrocolloids, fills in the knowledge gaps and provides formulators with key information about sugar beet pectin, (SBP), soybean soluble polysaccharide (SSPS), and gum arabic (GA) for stabilising oil-in-water (O/W) emulsions. "Although these hydrocolloids appear to function as an emulsifier in food systems in a comparable manner, there is no detailed comparison of their behaviours in O/W emulsions available, leading to our motivation of the present study," wrote lead author Makoto Nakauma from the Hydrocolloid Laboratory Section of San-Ei Gen F.F.I. Inc. 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, including collaborators from Glyn O. Phillips Hydrocolloid Research Centre (UK) and Osaka City University, evaluated the hydrocolloids in terms of the emulsion droplet-size distribution and adsorption behaviour at the oil-water interface. The necessary concentrations to stabilise the emulsions, containing a medium-chain triglyceride as the oil source (15 per cent), were found to differ between the hydrocolloids, with 1.5, 4.0, and 10.0 per cent necessary for SBP, SSPS, and GA, respectively. "Thus SBP required the smallest amount to cover the surface of the oil droplets and to activate the interface," stated Nakamura. A measure of the zeta potential of the emulsions, a measure of the stability of the emulsion, was reported to follow the order: SBP was greater than SSPS, which was greater than GA, "indicating that electrostatically SBP was the most effective in stabilizing the emulsions." The research also provides valuable information on the effect of pH and salts on the emulsifying properties of the hydrocolloids. "Both advantages and disadvantages of each hydrocolloid were clarified in variation of some formulation parameters encountered in the actual production of emulsions, contributing to the development of the emulsion technology," wrote the researchers. The research is ongoing, they stated, noting that a series of studies is planned. "Our overall goal in this projected series of studies is to identify strategies for controlling the quality of emulsions using food hydrocolloids based on the formulation and processing of the emulsions," wrote Nakamura and co-workers. Source: Food Hydrocolloids Published on-line ahead of print, doi: 10.1016/j.foodhyd.2007.09.004 "Comparison of sugar beet pectin, soybean soluble polysaccharide, and gum arabic as food emulsifiers. 1. Effect of concentration, pH, and salts on the emulsifying properties" Authors: M. Nakauma, T. Funami, S. Noda, S. Ishihara, S. Al-assaf, K. Nishinari, G.O. Phillips
