Scientists look to fish gelatin as emulsion stabilisers
gelatin as stabilisers for food emulsions, in keeping with the
trend to replace synthetic with natural emulsifiers.
Such fundamental research "has provided valuable information about the potential application of fish gelatins as emulsifiers in food products," wrote researchers from the University of Massachusetts behind a new study published in the journal Food Hydrocolloids (Vol. 20, pp. 596-606).
Emulsifiers are used by food makers to reduce the surface tension between two immiscible phases at their interface - such as two liquids, a liquid and a gas, or a liquid and a solid - allowing them to mix.
According to a recent report from Frost and Sullivan, the US market for food emulsifiers currently stands at around $505m, and is estimated to reach $668m by 2012.
Propelled by consumer health concerns, food makers are under increasing pressure to replace synthetic emulsifiers with more natural ones, said the Massachusetts researchers.
Indeed, such concerns have seen an increase in interest in ingredients such as fish gelatin, reported only for the first time in 2001 (Journal of Food Science, Vol. 66, No. 1, pp. 118-123).
Lead researcher, Professor D. Julian McClements, told FoodNavigator.com that ongoing research in this area has implications since the food industry "can use fish gelatin with less concerns about BSE (as with cow gelatin) or dietary concerns (e.g. as with pig or cow gelatin for vegetarians or ethnic populations)."
The new research looked at the stability, and therefore suitability, of fish gelatins in oil-in-water emulsions. Both low and high molecular weight fish gelatins were investigated.
The researchers examined the influence of concentration (from 0.5 to 6.0 per cent), the ability of the emulsions to form stable cream, and the stability when subjected to high salt concentration, thermal treatments and different pH values.
"Emulsions with monomodal particle size distributions and small mean droplet diameters could be produced at protein concentrations greater or equal to 4.0 per cent for both fish gelatins," reported lead author Jeonghee Surh.
Since the 4.0 per cent emulsions were associated with the most uniform particle sizes and there was limited evidence of destabilised oil, the remaining investigations used this fish gelatin concentration in the emulsions.
It was found that the low molecular weight fish gelatin (LMW-FG) more larger particles and more oil destabilisation than the HMW-FG.
Conversely, the LMW-FG was found to have a better creaming stability than the HMW-FG.
The researchers also report that the emulsions of both low- and high molecular weight fish gelatins were "fairly stable" when subjected to high salt concentration (250 millimoles of sodium chloride), thermal treatments (30 and 90 degrees Celsius for half and hour) and different pH values (pH 3 to 8).
"This study demonstrates that fish gelatin may have some limited use as a protein emulsifier in oil-in-water emulsions" wrote Surh.
Such basic research could provide valuable information to food formulators and research and developers considering alternative sources of stabilisers for emulsion for use in a wide range of products such as mayo, salad dressings, dips, sauces, beverages and so on.
Professor McClements told FoodNavigator that work was ongoing in this field.