Food science is a domain of life science. The intensity of changes during the freezing storage of frozen foods depends on several factors. The applications of low temperature are very common during the canning of fresh or processed foods. Many authors consider that changes in products are smallest if they are stored at low temperatures, which is also a kind of canning process.
Very often, before freezing, in the food industry, fresh fruits are blanched. Blanching is a process of short-term heat treatment for the purpose of denaturing enzymes that affect the color or in order to increase the softness of a product.
Studies conducted on the effect of freezing on the composition and properties of meat have shown that the freezing process (temperature, freezing rate), storage, and thawing conditions of previously frozen different food products affect their thermal properties. It is important to note at this point that water plays a crucial role in changing food properties during freezing.
Food products are multi-phase and multi-component metastable systems where several processes can occur simultaneously during the preparation process and the shelf life.
Applications of thermal analysis and calorimetry (TAC) to food products deal with many investigation targets spanning from the characterization of the systems at a molecular and supramolecular level to the description of the microbial metabolism.
Changes in foods during freezing and thawing can be rapidly determined
by differential scanning calorimetry (DSC). A scanning calorimeter is a type of calorimeter.
With DSC, there are typically two pans, one sample pan, and one reference pan. The sample pan contains the sample while the reference pan remains empty. Each pan is heated separately at a specific rate, and this rate is maintained throughout the experiment.
A computer system ensures that each pan heats up at the same rate, however, so that a measurement can be taken. The heater underneath the sample pan has to work harder than the empty reference pan, meaning it puts out more heat. The difference in the amount of heat put out is how a measurement is made.
Differential scanning calorimetry belongs to a group of thermal analyses based on measuring the heat flux difference between the sample and the reference substance, that is, the energy required to equalize the temperature between the sample and the
reference substance, during heating or cooling of the sample, under controlled conditions.
DSC is a thermal analysis technique to measure the temperature and heat flows associated with phase transitions in materials, as a function of time and temperature. DSC is particularly suitable for the analysis of food systems because they are often subject to heating or cooling during processing.
The calorimetric information from DSC can be directly used to understand the thermal transitions that the food system may undergo during processing or storage. DSC applications are used from troubleshooting up to new product developments.
In conclusion, DSC is used to study fat phase transitions and melting range. It is one technique used to explain the physical and textural properties of fats in bulk and final products.
- Schiraldi, A., Fessas, D. Calorimetry and thermal analysis in food science. J Therm Anal Calorim 138, 2721–2732 (2019). https://doi.org/10.1007/s10973-019-08166-z
- Radoslav, G., Danica, S., (2019) Thermal analysis of food products using differential scaning calorimetry (DSC) Contemporary Materials, X‒2 (2019)
- Patricia Heussen (2011), Practical food application of Differential Scanning Calorimeter. Retrieve from https://www.perkinelmer.com/CMSResources/Images/44129725APP_DSC_Food_Applications.pdf