Passive separation of waste ice cream

Authors: Garcia, Rafael; Plumier, Benjamin; LEE, CHANGHOON - Oak Ridge Institute For Science And Education (ORISE); LIANG, CHEN - Oak Ridge Institute For Science And Education (ORISE)

Submitted to: International Dairy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/15/2022
Publication Date: 1/9/2023
Citation: Garcia, R.A., Plumier, B.M., Lee, C., Liang, C. 2023. Passive separation of waste ice cream. International Dairy Journal. https://doi.org/10.1016/j.idairyj.2022.105570.
DOI: https://doi.org/10.1016/j.idairyj.2022.105570

Interpretive Summary: In ice cream manufacturing, routine occurrences such as product type changeover or packaging imperfections result in some product which is not suitable to send to market. Such product is discarded, despite being high quality, high value human food. The existing disposal options burden the industry or the environment, and result in total food loss. In this study, it is proposed that the butterfat in the waste ice cream may be profitably reclaimed and re-used. Doing so would recapture approximately 50% of the food energy and a large portion of the ingredient value. To explore the feasibility of this concept, the researchers used a wide variety of ice cream products and studied how quickly the butterfat in melted ice cream rises to the top and separates itself from the other ingredients. It was found that various ice cream products differ quite a bit in this respect, and the research shed some light on the source of the differences. Regardless of the differences between products, it was shown that heating and centrifuging both speed fat separation. In all cases, additional refining steps would be required to achieve the required purity. This first-of-its-type research lays the foundation for development of a butterfat recovery process that is cost effective and beneficial to manufacturers and the environment.

Technical Abstract: Ice cream manufacturers must waste a portion of their product, and butterfat is potentially a valuable and recoverable component of this waste. Little is known about the stability of the fat-in-water emulsion of commercial ice cream in the molten state. In the present study, examination of a wide variety of melted vanilla ice cream products reveals divergent separation patterns. Many products form upper foam layers (circa 20-30% fat) and/or lower translucent layers (c. 1% fat). Increased temperature and centrifugal acceleration both accelerate the development of these layers. Continuous phase density and viscosity measurement, as well as product label analysis, are used to investigate stability determinants, and the counter-intuitive observation of lower stability among products is reported. These results will support development of cost-effective butterfat recovery processes.