The effect of freezing and storage temperature on the stability of the fat emulsion in cream

The article presents the results of a study of frozen cream, the purpose of which was to assess the feasibility of using various freezing and storage modes to obtain a product with a stable fat phase. The objects of the study were cream samples of various fat contents (30%, 40% and 50%). Freezing was carried out at three temperature conditions (–50 °C, —25 °C and –18 °C) followed by storage for 4 months in refrigerators maintaining temperatures of –18 °C, —25 °C and –50 °C. Before and after low-temperature treatment, the state of the fat phase of the cream and the size of ice crystals were assessed using a microscopic method. Destabilization of fat dispersion was determined by the content of destabilized fat. It has been confirmed that with increasing mass fraction of fat in cream, the degree of destabilization increases. The amount of destabilized fat in cream samples with 30, 40 and 50% fat content before freezing was 14.3%, 20.0% and 32.0%, respectively. According to the research results, it has been revealed that when the freezing temperature decreases from –18 °C to –50 °C, there is no noticeable reduction in the amount of destabilized fat. The degree of destabilization decreased when cream was moved from lower to more gentle temperature conditions. At a storage temperature of –18 °C for cream previously frozen at –50 °C and –25 °C, the amount of destabilized fat in the cream was lower by 8.0–14.0% and 20.0–25.0%, respectively, in comparison with samples frozen and stored at the same temperature. When conducting microstructural studies, it has been revealed that freezing at a lower temperature with a change in storage temperature allows obtaining ice crystals with a smoother surface, which cause less damage to the membranes of fat globules.