Isochoric cooling process preserves dairy cream at subfreezing temperatures with freeze–thaw stability

Oil-in-water emulsions, such as dairy cream, can destabilise into an oily and an aqueous phase after freezing and thawing due to ice crystal formation. This work examined the freeze–thaw stability of dairy cream after isochoric cooling at subfreezing temperatures and conventional freezing (CF). Samples were processed under isochoric cooling conditions and under CF at −10°C, −15°C and −20°C. The stability of the emulsions was assessed by particle size distribution, visual appearance, confocal micrographs, amounts of destabilised serum, rheological properties and colour properties, as well as lipid oxidation and microbial growth after 14 days. Dairy creams conventionally frozen at these temperatures destabilised into a serum phase and a precipitate due to ice formation that caused partial and complete coalescence of the fat globules. In comparison, dairy cream samples stored under isochoric conditions showed greater stability than the control sample stored in refrigeration at 5°C, due to the absence of ice crystals and low processing temperatures. Also, no microbial growth, significant changes in flow behaviour, colour or lipid oxidation occurred for the isochoric samples. These results showed that isochoric cooling can be used to preserve dairy cream at subfreezing temperatures with no freeze–thaw destabilisation.