Abstract
The results presented in this study confirm previous knowledge and stress the need for both hydrophobic emulsifiers and submicronial fat particles to stabilize water-in-vegetable oil emulsions. It was demonstrated that polyglycerol polyricinoleate (PGPR) is superior to glycerol monooleate and/or lecithin, but is incapable of stabilizing these fluid emulsions for sufficient storage periods. Fluid emulsions, unlike margarine, exhibit high droplet mobility and are susceptible to flocculation and coalescence. It was also demonstrated that submicronial αform crystals of hydrogenated fat can be obtained in the oil phase by the flash-cooling process. The crystals are homogeneously almost mono-dispersed and exhibit insufficient stability against flocculation and phase separation. The use of an emulsifier (PGPR) in the fat crystallization process was very helpful in decreasing the aggregation and flocculation processes. The αform (mixed with β′-form) submicronial crystals can stabilize water-in-oil emulsions only in the presence of food emulsifiers, provided the concentration of tristearin is limited to 1.0-2.0 wt% (to prevent phase separation and high viscosity) and the PGPR is added at sufficient concentrations (PGPR/tristearin ratio of 2.0 or more). Ideally stable (for over 6-8 wk) fluid emulsions can be formed in systems composed of fat submicrocrystalline hydrophilic particles and food-grade emulsifiers. These water-in-oil emulsions can serve as the basic preparation for any foodgrade water-in-oil-in-water double emulsion.
Original language | English |
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Pages (from-to) | 1825-1831 |
Number of pages | 7 |
Journal | JAOCS, Journal of the American Oil Chemists' Society |
Volume | 75 |
Issue number | 12 |
DOIs | |
State | Published - 1998 |
Keywords
- Differential scanning calorimetry
- Pickering stabilization
- Polyglycerol polyricinoleate
- Polymorphism
- Solid particle stabilization
- Steric stabilization
- Submicronial fat crystals
- Water-in-oil emulsions
- X-ray
- α-form of tristearin