A Prototype Process for Demulsification of Waste Ice Cream

Recovery of the butterfat in waste ice cream may be an opportunity to mitigate food and economic loss. Previous efforts to recover such fat have succeeded in producing a fat-enriched fraction but have not succeeded in demulsifying the fat. In the present study, a method involving a sequence of emulsion-breaking steps is shown to be effective for releasing a majority of the fat from waste ice cream as free, unemulsified oil. The effect of altering process conditions including enzyme type, pH, and incubation temperature is reported. Depending on the test conditions and the variety of ice cream used, typically 59%-81% of the fat was recovered, with varying degrees of hydrolytic and oxidative damage. As the method is relatively complex, an experiment which omitted individual processing steps demonstrated that each step was required for high recovery. Success with 4 of 5 tested varieties showed that the method has reasonably broad applicability. The results are compared with those achieved using a standardized solvent extraction method. Finally, the method is evaluated for its potential as the basis for a commercial WIC fat recovery process.