It is known that the presence of a fine microstructure is critical to produce an ice cream that has a creamy texture and has good meltdown properties.
However the microstructure produced in a conventional ice cream freezer (e.g. a scraped surface heat exchanger) has been found to be unstable and both ice crystals and gas bubbles coarsen significantly in the time taken to harden the product to typical storage temperatures of −25 C. An important step to maintain the desired microstructure is to stabilise the gas bubbles during hardening. This is achieved by generating a partial network of fat aggregates adsorbed onto the air interface to provide a steric barrier to gas cell coalescence. To generate this fat network, a proportion of the oil droplets need to partially coalesce as a consequence of the shear regime encountered within the ice cream freezer. In order to control this process of fat destabilisation, so called destabilising emulsifiers are often used to displace milk protein at the oil:water interface and generate higher levels of fat destabilisation. Thus, the presence of a destabilised fat network prevents excessive gas bubble coarsening and helps maintain the desired fine microstructure.
Up to now, this has been achieved by using chemical products which are more and more perceived by consumers as being negative and/or detrimental to the environment or to human health. There is therefore a need for finding and using destabilising emulsifiers which could be used with an “all natural” composition.
It has now been found that such destabilising emulsifiers exist in eggs and can be extracted by centrifugation.