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 1 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 foam having a continuous lipid phase and a porosity between 1 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, and the foam does not have a rigid network of crystals between the gas bubbles.
2. The foam according to claim 1 , wherein the crystals comprising triglycerides occupying the surface of the gas bubbles form layers having an average thickness below 5 μm.
3. The foam according to claim 1 , wherein the lipid phase comprises one or more fats and the crystals comprising triglycerides occupying the surface of the gas bubbles comprise triglycerides from all the one or more fats.
4. The foam according to claim 1 , wherein the lipid phase comprises one or more higher melting-point fats and one or more lower melting-point fats and wherein the melting-point of the lowest melting higher melting-point fat is at least 10° C. above that of the melting point of the highest melting lower melting-point fat and wherein the lower melting-point fats are present at a level of greater than 50 wt. % of the total lipid in the lipid phase.
5. The foam according to claim 4 , 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, fractions and combinations of these; 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 and fractions of these.
6. The foam according to claim 1 , wherein solid particles having a particle size of less than 500 μm are dispersed in the foam.
7. The foam according to claim 6 , 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.
8. The foam according to claim 1 , 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, and the foam contains less than 5 wt. % of water.
9. The foam according to claim 1 , having a solid lipid content between 5% and 20%, and the foam is a gel having a linear shear elastic modulus G′ of 10 2 -10 7 Pa at 1 Hz.
10. A product comprising a foam comprising a continuous lipid phase and a porosity of between 1 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, and the foam does not have a rigid network of crystals between the gas bubbles, wherein the product is a food product or a cosmetic product.