Quick-freezing based on a nitrogen reversed Brayton cryocooler prototype: Effects on the physicochemical characteristics of beef longissimus thoracis muscle

Freezing plays an important role in food preservation and shelf-life extension. This study assessed the effectiveness of an innovative quick-freezing plant for meat freezing, based on a nitrogen reversed Brayton cryocooler prototype able to reach very cold temperatures (< −100 °C), by evaluating the effects on the physicochemical characteristics of frozen/thawed beef steaks. A comparison with two other standard freezing methods was conducted, and unfrozen beef steaks were used as a reference. The time-temperature profiles were monitored during the freezing and thawing processes, and physicochemical analyses were performed on unfrozen and thawed steaks. The results of the experimental campaign showed that the prototype plant made it possible to achieve a faster freezing rate (50 °C h−1) than standard plants, leading to a significant reduction in the thawing losses of frozen meat. In addition, the steaks processed in the prototype plant had larger hue values, indicating less red colour.