Isochoric cooling process preserves dairy cream with freeze-thaw stability

Authors: Bilbao-Sainz, Cristina; Olsen, Carl; Chiou, Bor Sen; Wood, Delilah; McHugh, Tara; RUBINSKY, BORIS - University Of California Berkeley

Submitted to: International Journal of Dairy Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/18/2025
Publication Date: 3/13/2025
Citation: Bilbao-Sainz, C., Olsen, C.W., Chiou, B., Wood, D.F., McHugh, T.H., Rubinsky, B. 2025. Isochoric cooling process preserves dairy cream with freeze-thaw stability. International Journal of Dairy Technology. 78(1). https://doi.org/10.1111/1471-0307.70003.
DOI: https://doi.org/10.1111/1471-0307.70003

Interpretive Summary: Many types of foods contain oil-in-water emulsions, including milks, creams, fruit beverages, desserts, dressings and sauces. Some of these foods could benefit from frozen storage to increase their shelf-life. However, freeze–thaw destabilization of emulsion-based food products has been a major impediment to freezing. The thawed products have texture changes, mouthfeel changes and off-flavors as well as undesirable appearances. They can also destabilize into an oily and an aqueous phase. In this study, we used commercial dairy cream as a food emulsion model to evaluate the potential use of isochoric freezing to preserve emulsion-based products with freeze-thaw stability. We compared the effects of refrigeration, isochoric and conventional freezing on the physical stability and physico-chemical characteristics of dairy cream. Dairy cream subjected to conventional freeze–thawing was highly unstable due to the formation of ice crystals that promoted extensive fat droplet coalescence and protein coagulation. In comparison, cream frozen under isochoric conditions did not result in the usual phase separation after thawing due to the absence of ice crystal formation during freezing. Also, isochoric freezing preserved the cream’s viscosity and color. In addition, no lipid oxidation or microbial growth occurred in the isochoric samples.

Technical Abstract: This work examined the freeze-thaw stability of dairy cream after isochoric freezing compared with conventional freezing. Samples were first frozen at -10 °C, -15 °C and -20 °C for 14 days and thawed to room temperature. Their stability was assessed by particle size distribution, visual appearance, confocal micrographs, amounts of destabilized serum, rheological properties and color properties as well as lipid oxidation and microbial growth. Conventionally frozen dairy creams destabilized into a serum phase and a precipitate due to ice formation during freezing that caused precipitation of the caseinate system and the destruction of the fat emulsion. In comparison, dairy cream samples were stable after isochoric freezing. In fact, isochoric freezing resulted in significant reductions of the fat globule size, which led to samples with greater stability than the control sample stored in refrigeration at 5 °C. In addition, no microbial growth or significant changes in flow behavior, color and lipid oxidation occurred for the isochoric samples. These results showed that isochoric freezing can be used to extend the shelf-life of dairy cream by storing at subfreezing temperatures with no freeze–thaw destabilization.