Process for preparing fat continuous emulsions containing protein
A process for preparing a water-in-oil emulsion which emulsion comprises protein, oil and a hardstock fat. The process involves blending the melted hardstock fat with a water-continuous dispersion comprising protein and oil, wherein the temperature of the aqueous dispersion being mixed with the melted hardstock fat is below 15° C., and said mixing is carried out by a high shear mixing device followed by a pin-stirrer.
1. A process for preparing a fat-continuous emulsion, which emulsion comprises 30-70% of an aqueous phase, said aqueous phase comprising 0.1-2% protein, by weight of the total emulsion, and 30-70% of a fat phase, said fat phase comprising 5-80% hardstock, and 20-95% oil by weight of the total fat phase, wherein the process comprises the steps of:
a) providing a water-continuous dispersion at a temperature of between 0° C. and 15° C. comprising water as a continuous phase with dispersed therein oil and further comprising protein, wherein the water-continuous dispersion does not contain midstock fat fraction crystals;
b) providing the melted hardstock fat at a temperature of between 30° C. and 60° C.;
c) combining the water-continuous dispersion of step a) with the melted hardstock fat of step b);
d) subjecting the mixture obtained after step c) to high shear imparted by a high shear device to provide a fat-continuous emulsion, wherein the high shear device is a high shear mixing process in a high shear mixer having a rotor and a stator, and wherein the mixer has a residence time of less than 3 seconds, and sufficient shear to effect emulsification of water droplets in oil having a droplet size d3,3 of less than 15 micrometer; and
e) subjecting the emulsion obtained from step d) to working by a pin-stirrer;
wherein the temperature of the mixture obtained from step c. is below the melting point of the hardstock fat.
2. The process of claim 1 , wherein all of the aqueous phase and all of the oil phase of the final product are part of the water-continuous dispersion of step a).
3. The process of claim 1 , wherein the dispersion of step a) is obtained by mixing continuously in-line the aqueous continuous phase with the oil.
4. The process of claim 1 , wherein the dispersion of step a) is obtained by providing a stirred tank comprising the oil dispersed in the aqueous phase.
5. The process of claim 1 , wherein the temperature of the aqueous dispersion in step a) is between 0 and 10° C.
6. The process of claim 1 , wherein the temperature of the melted hardstock in step b) is between 30 and 55° C.
7. The process of claim 1 , wherein the residence time of the emulsion in the pin stirrer in step e) is between 15 seconds and 4 minutes, and wherein the stirrer in the pin stirrer has a rotation speed of between 50 and 300 rpm.
8. The process of claim 1 , wherein the fat phase comprises less than 1% of trans-unsaturated fatty acids, by weight of the total fat phase of the emulsion.
9. The process of claim 1 , wherein the protein is a non-gelling protein.
10. The process of claim 9 , wherein the non-gelling protein is a dairy protein.
11. The process of claim 1 , wherein the emulsion does not contain a gelling protein or a gelling carbohydrate.
12. The process of claim 1 , wherein the fat continuous emulsion is a spreadable emulsion.
13. The process of claim 1 , wherein the temperature of the melted hardstock in step b) is between 35° C. and 45° C.