Role of Cryogenics in Food Processing and Preservation

Abstract

Food materials are perishable by nature. They require processing or preservation techniques to enhance the storage life. Cryogenics is a branch of engineering wherein production of cryogen and the maintenance of low temperature technologies are studied. One such cryogen, liquid nitrogen (LN2) has a tremendous potential to be used as a total loss refrigerant. In this paper, the different aspects of the utilization of LN2 as a refrigerant and as a gas are discussed in details.In freezing for individual quick freezing LN2 can be used as a refrigerant to get an ultra rapid freezing. Due to its rapidity LN2 freezing is capable of producing small ice crystals in size and there by helps immensely in retaining quality reducing substantial amount of drip loss.LN2 has gained tremendous popularity for the transportation of frozen foods. Apart from the intermittent spraying of LN2, dump charging method has been also developed wherein the refrigerant required for a point to point transportation is supplied to a frozen cargo before the commencement of the journey eliminating the requirement of LN2 vessel to be taken on board.Grinding is a technique which reduces the size of spices, considerably increasing the surface area available to impart flavor to any prepared food. Unfortunately, a substantial amount of flavoring compounds is lost due to the increase in temperature while using conventional grinding methods. LN2 can act as a rescuer for retention of quality by reducing the spice as well as grinder temperature substantially. Experimental analysis reveals that the loss of volatile component and particle size distribution of the ground spices are more than the satisfaction level of the processor.LN2 has the capacity to both lower the temperature and flush off the inside air of a closed container. This serves a dual purpose: The temperature of the closed chamber is brought to the desired level almost instantaneously and the gas compost ion can be changed immediately. The application of LN2 helps to minimize the need for high-capacity refrigeration system. Only 10% of the installation capacity is required for maintaining the desired temperature.