Process for preparing a fat slurry and for preparing a spread with said slurry
A process for preparing a slurry of edible oil and fat powder, and to a process of preparing an edible fat-continuous spread out of such. The process for preparing said slurry has at least two different regimes of reduced pressure.
1. Process for preparing an edible fat slurry comprising 70-98% by weight (of the total slurry of oil and fat powder) of an edible oil and 2-30% by weight (of the total slurry of oil and fat powder) of fat powder, wherein the fat powder is a micronised fat powder of a structuring fat, said process comprising the steps of:
a) providing the fat powder;
b) providing the oil;
c) combining the fat powder and the oil in a mixing vessel;
d) mixing the oil and fat powder in the mixing vessel to a fat slurry for a period of 1 to 8 minutes at a pressure of below 0.25 bar;
e) subjecting the mixing vessel to a pressurising step of 30 seconds to 6 minutes to raise the pressure in the mixing vessel to at least 0.3 bar, during which the shear in the mixing vessel is less than the shear in step g);
f) subjecting the mixing vessel to a de-pressurising step of 1 to 10 minutes to reduce the pressure in the mixing vessel to below 0.25 bar; and
g) subjecting the content of the mixing vessel to a stirring operation for 3 to 10 minutes;
wherein the temperature of the fat powder, oil phase, and mixture thereof is kept at a temperature of below 35° C.
2. The process of claim 1 , wherein the successive steps e) to g) are repeated at least once.
3. The process of claim 2 , wherein the successive steps e) to g) are repeated until the viscosity of the content in the mixing vessel has reached a viscosity of at least 8 dPa·s.
4. The process of claim 1 , wherein the pressure in steps d) and f) is reduced to below 0.2 bar.
5. The process of claim 1 , wherein the de-pressurising step f) and the mixing step g) are effected in a total time of 2 to 10 minutes.
6. The process of claim 1 , wherein after step g) the pressure is brought up to atmospheric pressure.
7. The process of claim 1 , wherein the oil and the fat powder are mixed by one or more of (a) recirculation means, (b) a dynamic mixer, and (c) a stirrer in the mixing vessel.
8. The process of claim 7 , wherein recirculation means comprises an in-line mixer.
9. The process of claim 8 , wherein the stirring operation in step g) is carried out for at least the time equal to the average residence time in the vessel with recirculation means.
10. The process of claim 1 , wherein the amount fat powder on the total fat slurry is from 2 to 20% by weight, based on the total fat slurry.
11. The process of claim 1 , wherein the pressure at step e) is raised in the mixing vessel to from 0.3 to 0.7 bar.
12. The process of claim 5 , wherein the de-pressurising step f) and the mixing step g) are effected in a total time of 3 to 8 minutes.
13. The process of claim 1 , wherein the pressure in steps d) and f) is reduced to below 0.1 bar.
14. The process of claim 2 , wherein the successive steps e) to g) are repeated until the viscosity of the content in the mixing vessel has reached a viscosity of at least 10 dPa·s.
15. A process for making an edible oil-continuous emulsion containing 15-80% (by weight of the total emulsion) of a fat phase and 20-85% (by weight of the total emulsion) of an aqueous phase, which process comprises the steps of
a) providing the aqueous phase at a temperature below 35° C.,
b) providing a fat slurry of oil and fat powder,
c) mixing said aqueous phase and said fat slurry to obtain an oil-continuous emulsion,
wherein said fat slurry is obtained by the process comprising the steps of claim 1 .