46C-5 |
Characterization of a double emulsion system (oil-in-water-in-oil emulsion) with low solid fats: Microstructure |
F. JAHANIAVAL1, Y. Kakuda1, V. Abraham2, and M. F. Marcone1. (1) Department of Food Science, University of Guelph, Guelph, ON., N1G 2W1, Canada, (2) Caravelle Foods, Brampton, ON., Canada A double emulsion system (oil-in-water-in-oil (O/W/O)) with 16% water and 80% oil was prepared and stabilized using a novel method. The objective was to insert fat crystals in the form of plastic fat between the oil globules and stabilize it with only 4% added solids. The method was to mix two oil-in-water emulsions together in which the first emulsion consisted of 85% liquid canola oil, 14% water, 0.6% sodium caseinate and 0.4% lecithin and the second emulsion contained 67% canola oil, 8% palm-cotton stearin, 0.4% lecithin, 18% water, 6% whey powder and 0.6% sodium caseinate. Mixing the two emulsions (50:50) by weight produced a product with 76% liquid canola oil and 4% solid fat (palm-cotton stearin). The two O/W emulsions were prepared separately at 50°C then mixed together at 45°C for 2-5 min and then supercooled to -5°C. Results showed that under cooling conditions the second emulsion droplets (containing liquid oil and solid fat) were disrupted due to the growth of fat crystals and resulted in the released of plastic fat. The release of plastic fat resulted in the inversion of the continuous phase. The emulsion viscosity dropped from 37,000-50,000cps to 250cps at this stage. The released plastic fat continued to harden due to crystallization of the hard fraction and stabilized the first O/W emulsion (containing only liquid oil). Microstructural analysis showed that the fat globules in the first emulsion remained intact during mixing and supercooling of the two O/W emulsions. A stable O/W/O emulsion was formed with plastic fat as the continuous phase and the first O/W emulsion as the dispersed phase. The significance of this work was to stabilize a high liquid oil product with only 4% added solid fat.
Session 46C, Food Chemistry: Lipids, antioxidants and emulsifiers
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