What is the thermopenetration concept?

The pasteurization of products packed in glass containers leads to a problem of a specific nature, which is referred to as 'thermopenetration'. What is the thermopenetration concept? Let's find out.

The thermopenetration problem is very important, particularly in the case of the pasteurization of products packed in glass containers, as it is the ascertaining factor for the success of the whole operation. Throughout pasteurization it is essential that a sufficient heat quantity is transferred via the receptacle walls; this is in order that the product temperature rises adequately to be lethal to microorganisms all through the product mass. The most suitable and practical process to speed up thermopenetration is the movement of receptacles during the pasteurization process. Rapid rotation of receptacles in the region of their axis is an efficient means to accelerate heat transfer, because this has the effect, between others of rapidly mixing the contents. The critical speed of for this movement is usually about 70 rotations per minute (RPM). This allows a more uniform heating of products, decreasing heating time and organoleptic degradation. Heating may come first or follow packaging. It is suitable to separate heat preservation practices into two broad categories: one includes heating of foods in their final containers, the other uses heat prior to packaging. The latter category involves methods that are inherently less damaging to food quality, in which the food can be willingly subdivided (such as liquids) for rapid heat exchange. Though, these methods then need packaging under aseptic or nearly aseptic conditions to prevent or at least minimise recontamination. Alternatively, heating within the package often is less costly and produces quite acceptable quality with the majority of foods and most of our present canned food supply is heated in the package. Tetra pack available in the market for fruit juices are the best instances for aseptic packaging.