Method of producing a blended freeze dried, spray dried soluble coffee powder
The present invention relates to a method of producing a freeze dried soluble coffee powder which produces foam when dissolved in water. The method involves partly melting the surface of a granulated frozen coffee extract and mixing it with a porous spray dried coffee powder whereby the porous spray dried powder particles stick to the surface of the granulated frozen coffee extract particles, and freeze drying the particles.
1. A method of producing a soluble coffee powder, the method comprising:
a) providing a porous spray dried soluble coffee powder having a particle size between about 10 and about 300 microns;
b) providing a granulated frozen coffee extract by injecting gas into a liquid coffee extract, freezing the gas-injected liquid coffee extract, and granulating the frozen gas-injected coffee extract, wherein the frozen granulated coffee extract has a particle size between about 500 and about 3600 microns;
c) heating the granulated frozen coffee extract to partly melt the powder surface;
d) mixing the porous spray dried coffee powder with the heated granulated frozen coffee extract to produce particles of the frozen coffee extract covered by particles of the porous spray dried coffee powder, wherein the particles of the porous spray dried coffee powder adhere to and coat the particles of the granulated frozen coffee extract; and
e) freeze drying the covered particles of frozen coffee extract obtained in step d) to obtain the soluble coffee powder,
wherein the soluble coffee powder produces a foam volume of at least about 1 mL when 5 g of the soluble coffee powder is dissolved in 200 mL water at 90° C.
2. The method of claim 1 , wherein the porous spray dried soluble coffee powder is provided by injecting gas into a liquid coffee extract and spray drying the gas injected liquid coffee extract.
3. The method of claim 1 , wherein a weight ratio of the porous spray dried powder and the granulated frozen coffee extract is between about 66:33 and about 20:80 during the mixing of step d).
4. The method of claim 1 , wherein the frozen granulated coffee extract provided in step b) has a water content between about 25 and about 75% by weight.
5. The method of claim 1 , wherein the porous spray dried soluble coffee powder provided in step a) has a porosity of at least about 55%.
6. The method of claim 1 , wherein pores of the porous spray dried soluble coffee powder provided in step a) have an average diameter D 50 of less than about 80 microns.
7. The method of claim 1 , wherein pores of the porous spray dried soluble coffee powder provided in step a) have a distribution span factor of less than about 4.
8. A method of producing a soluble coffee powder, the method comprising:
a) providing a porous spray dried soluble coffee powder having a particle size between about 10 and about 300 microns;
b) providing a granulated frozen coffee extract by injecting gas into a liquid coffee extract, freezing the gas-injected liquid coffee extract, and granulating the frozen gas-injected coffee extract, wherein the frozen granulated coffee extract has a particle size between about 500 and about 3600 microns;
c) mixing the porous spray dried coffee powder with the granulated frozen coffee extract to produce particles of the frozen coffee extract covered by particles of the porous spray dried coffee powder;
d) heating the granulated frozen coffee extract after and/or during the mixing in step c) to partly melt the powder surface, wherein the particles of the porous spray dried coffee powder adhere to and coat the particles of the granulated frozen coffee extract; and
e) freeze drying the covered particles of frozen coffee extract obtained in step d), wherein the soluble coffee powder produces a foam volume of at least about 1 mL when 5 g of the soluble coffee powder is dissolved in 200 mL water at 90° C.
9. The method of claim 1 , wherein the method does not include sintering.
10. The method of claim 8 , wherein the method does not include sintering.