ABSTRACT
In the past, the availability of fresh vegetables depended on the geographic proximity of the place of harvest and not on modern food preservation technologies. The use of low temperatures in the form of refrigeration and freezing, which are food technologies that increase the shelf life of perishable food products like vegetables, increases the availability of these important foods throughout the year and in faraway places of harvest. Refrigeration increases the vegetable shelf life in days or weeks, while vegetable freezing prolongs shelf life in general in months or years. Refrigeration of vegetable requires removal of the sensible heat and also the respiratory heat of products since metabolic activity continues. Conversely, frozen vegetables have no metabolic activity and therefore do not produce respiratory heat, but the freezing operation must remove the sensible heat and the latent heat to produce necessary change state. Refrigeration and freezing of vegetables require a series of uninterrupted operations, called cold chain, which ensures that the applied technology (refrigeration or freezing) is effective in preserving the quality of the raw material, so you have used high-quality raw material (vegetable) to be frozen or refrigerated, the temperature should be decreased as quickly as possible, and then the storage temperature (refrigeration or freezing) should be kept constant to the consumer.
