Rapid continuous freezing of liquid food products

Abstract

The segregation of dissolved food (e.g. milk) solids during freezing has been exploited as a water separation approach, but the application of freezing to bulk volumes commonly causes product component degradation, and the time required for thawing large blocks of frozen milk (and other liquid foods) incurs a risk of significant microbial growth.

For some milk supplies, notably non-bovine milk, common processes such as spray drying require a scale of operation that is too large for common collection-volumes. Market opportunities for such milk supplies would improve if it were possible to accumulate larger volumes without product degradation. A freezing process would meet this need if product degradation could be avoided.

Detailed microscopic and theoretical investigation of the freezing of milk-type substances has revealed a freezing mechanism that may be exploited to allow rapid continuous freezing into pellets, enabling storage/accumulation and rapid thawing on demand.

This paper describes the process functional parameters needed for rapid freezing and thawing, summarises the science findings and reports application of those findings to the development of a prototype continuous rapid freezing unit that shows significant promise.

We also report initial testing to clarify the likely scope of application, to provide evidence of energy efficiencies, and to provide evidence of preservation of product qualities following freezing, storage and thawing.