Temperature-pressure correlations of cryoprotective additives for the design of constant volume cryopreservation protocols.

In the recent years, the use of constant volume (isochoric) cryopreservation, in medicine and biotechnology has captured more attention from the research community and now there is an increasing interest in the use of this new technology. It has been established that the thermodynamics of isochoric freezing is different from that of isobaric (constant pressure) freezing. This study provides researchers in the field experimental results for various compositions of cryoprotectants commonly used in isobaric cryopreservation, in terms of temperature-pressure-molar concentration correlation. It also reveals experimental isochoric thermodynamic data for the following cryoprotectants, commonly used in isobaric cryopreservation: dimethyl sulfoxide, trehalose, ethylene glycol and diethylene glycol. Currently, the data on the pressure-temperature correlation in an isochoric system of cryoprotectants used in isobaric cryopreservation is not available. Our new experimental results indicate that the studied concentrations for each of the CPAs, lower and expands the range of temperatures in which cryopreservation by isochoric freezing can be safely practiced. We consider that these experiments will aid researchers developing new isochoric cryopreservation protocols.

A comparison of raspberry freezing-damage during preservation in isochoric and isobaric conditions.

Introduction: Fruits are perishable, thus it's crucial to have an efficient preservation technique that can increase storage time while keeping physical quality and nutritional attributes in order to avoid wastage. The majority of methods for long-term storage require refrigeration. Methods: In this investigation, we assess the viability of isochoric freezing as a different technique of raspberry (Rubus idaeus L.) preservation. Raspberries were subjected to different storage conditions: isochoric freezing at -4°C, conventional isobaric settings at +3°C (refrigerator), -21°C (freezer), and -4°C with a trehalose solution in a plastic bag. The study assessed changes in weight loss, visual appearance, color, hardness, °Brix values, and pH over a seven-day period. Results: Key findings reveal that raspberries subjected to isochoric freezing below the freezing point of water experienced minimal weight loss after seven days. Visual appearance, color, hardness, °Brix values, and pH were comparable to fresh raspberries, indicating minimal alteration. Discussion: These results suggest that isochoric freezing shows potential as a preservation method that maintains the physical and chemical properties of raspberries similar to fresh fruit. Implementing diverse preservation techniques tailored to raspberries may contribute to environmental sustainability by reducing food wastage and the associated environmental impact.