Application of Supercooling for the Enhanced Shelf Life of Asparagus (Asparagus officinalis L.)

Freezing extends the shelf-life of food by slowing down the physical and biochemical reactions; however, ice crystal formation can result in irreversible damage to the cell’s structure and texture. Supercooling technology has the potential to preserve the original freshness of food without freezing damage. In this study, fresh asparagus was preserved in a supercooled state and its quality changes such as color, weight loss, texture, chlorophyll and anthocyanin content, and enzymatic activities (superoxide dismutase and catalase) were evaluated. The asparagus samples were successfully supercooled at −3 °C with the combination treatment of pulsed electric field (PEF) and oscillating magnetic field (OMF), and the supercooled state was maintained for up to 14 days. Asparagus spears preserved in the supercooled state exhibited lower weight loss and higher levels of quality factors in comparison to the frozen and refrigerated control samples.

To the development of scientifically based storage modes of meat and meat products in a supercooling state

One of the ways to ensure safety, preserve quality and increase the expiration date (storage) of meat with minimal technological processing of raw materials is the use of supercooling and storage technologies at subcryoscopic temperatures. Supercooling is a refrigeration processing process that provides lowering the meat temperature (1–2 °C) below the cryoscopic temperature without phase transformation of water into ice (supercooling). The phase transformation of water into ice upon freezing and freezing food products causes irreversible changes in them as a result of crystal formation in muscle fibers, decompartmentalization of cell organelles and denaturation of sarcoplasmic and myofibrillar proteins. Subcooling provides better quality preservation and an increase in the expiration date of meat raw materials and finished meat products compared to cooling. To ensure a stable supercooled state of products at a subcryoscopic temperature, studies of the influence of abiotic and anabiotic factors on the limiting temperature of supercooling (nucleation) of a product are of great importance. The article presents the results of studies on the impact of quality meat groups, packaging and the temperature of the cooling medium on the stability indicators of the supercooled state of raw materials and finished products. It is shown that the temperature of the cooling medium, providing a stable state of the product undercooling, lies between its cryoscopic and the limiting temperature of the supercooling, experimentally determined for each type of product.

Investigation of the Effect of Oscillating Magnetic Field on Fresh-Cut Pineapple and Agar Gel as a Model Food During Supercooling Preservation

In this study, the effect of an oscillating magnetic field (OMF) on the supercooling of fresh-cut pineapple and agar gel was investigated. The pineapple was preserved in a supercooled state at -7°C, and its supercooled state was maintained for 14 days with the presence of the OMF, whereas the untreated sample was spontaneously nucleated within 24 h. Agar gel was prepared as equivalent to the soluble solids content of pineapple and showed a comparable supercooling behavior when exposed to a similar OMF treatment. Examination of the microstructures showed that cellular damage due to ice crystal formation did not occur in the supercooled pineapple and agar gel, implying that the OMF successfully inhibited ice nucleation during supercooling. The weight losses of pineapple samples preserved with refrigeration, freezing, and supercooling for 14 days were determined to be 7.3%, 23.8%, and 0.8%, respectively. Furthermore, the visual appearance showed that supercooling effectively prolonged the shelf-life of pineapple without freezing damage. The results suggest that the developed OMF technology can inhibit ice nucleation during supercooling and can be used to preserve fresh-cut fruits at subzero temperature while ensuring the food quality. In addition, a solid model food could be used as a substitute for predicting the supercooling behavior of food products. Keywords: Food preservation, Fresh-cut fruit, Oscillating magnetic field, Pineapple, Supercooling.