Lipid based foam
The present invention relates generally to the field of foams. One aspect of the invention provides a foam having a continuous lipid phase and a porosity of between and 80% wherein, at a temperature at which the lipid phase has a solid lipid content between 0.1 and 80% the foam comprises gas bubbles having at least 50% of their surface occupied by crystals comprising triglycerides. Further aspects of the invention are a product comprising a foam and a process for forming a foam.
1. A process for forming a foam, the process comprising:
providing a composition comprising triglycerides and having a lipid content greater than 20 wt. %, wherein the triglycerides are more than 95 wt. % of the total lipids of the foam, and all fatty acids in the triglycerides have a carbon chain length less than 22;
cooling the composition to a temperature between 0° C. and 15° C. such that the composition comprises triglyceride crystals, has a solid lipid content between 5% and 20% and forms a gel having a linear shear elastic modulus G′ of 10 2 -10 7 Pa at 1 Hz; and
aerating the gel to form a foam comprising bubbles, and the foam does not have a rigid network of crystals between the bubbles, wherein the aerating of the gel comprises mechanical agitation, and the foam contains less than 5 wt. % of water.
2. The process according to claim 1 , further comprising adding solid particles having a particle size of less than 500 μm to the composition comprising triglycerides.
3. The process according to claim 1 , wherein triglyceride crystals are added to the composition comprising triglycerides.
4. The process according to claim 1 , wherein the composition comprising triglycerides is initially at a temperature at which the composition comprising triglycerides contains less than 0.1% solid lipid.
5. The process according to claim 1 , wherein there is a time interval of at least 5 minutes between the formation of the gel and the start of the aeration.
6. The process according to claim 1 , wherein the aeration comprises gas depressurization followed by mechanical whipping.
7. The process according to claim 1 , further comprising adding additional food ingredients to the foam and forming a food product.
8. The process according to claim 1 , wherein the foam comprises gas bubbles having at least 50% of their surface occupied by crystals comprising triglycerides.
9. The process according to claim 8 , wherein the crystals comprising triglycerides occupying the surface of the gas bubbles form layers having an average thickness below 5 μm.
10. The process according to claim 1 , wherein the foam has a continuous lipid phase and a porosity between 1 and 80%.
11. The process according to claim 10 , wherein the lipid phase comprises one or more higher melting-point fats and one or more lower melting-point fats and wherein the lowest melting-point of the higher melting-point fats is at least 10° C. above that of the highest melting point of the lower melting-point fats, and wherein the lower melting-point fats are present at a level of greater than 50 wt. % of the total lipids in the lipid phase.
12. The process according to claim 11 , wherein the one or more higher melting-point fats are selected from the group consisting of cocoa butter, shea butter, illipe butter, sal fat, kokum butter, mango kernel fat, palm kernel oil, palm oil, coconut oil, milk fat, high stearic sunflower oil and hydrogenation products, inter-esterification products and combinations thereof and the one or more lower melting-point fats are selected from the group consisting of sunflower oil, safflower oil, rapeseed oil, olive oil and combinations thereof.
13. The process according to claim 2 , wherein the solid particles are selected from the group consisting of modified starch, maltodextrin, inorganic salt, protein particles, fibres, plant particles, sugars, hydrogel particles and combinations thereof.