Precooling process

A precooling process is very critical for maintaining fruit’s produce quality and extending their shelf life. The process rapidly lowers the temperature and it is done immediately following a harvest to minimize spoilage.

Several methods are commercially employed to precool produce, these are:

• Air/Room cooling

• Ice cooling

• Hydro-cooling

• Vacuum cooling

• Forced-air cooling

Air-cooling

Air or Room cooling typically uses low energy, it’s a slow process and ideal for those produce that are sensitive to surface moisture. The produce are placed in a room where they are allowed to cool by cold air

Hydro cooling

Hydro-cooling is faster process compared than air cooling, but it’s more expensive. Faster process means that this process can have some issue that can affect some produce, for instance, it can spread pathogen, hence can only be used on few fruits types or the leafy vegetables.

Ice cooling

In ice-cooling, fine granules of ice are used to cool the produce. The process is much higher than hydro-cooling since ice has a higher heat removal capacity compared to water, however, it can add weight.

Vacuum cooling

Vacuum cooling method is very rapid and energy efficient. In this method vacuum is created in an airtight chamber by evacuating air, thereby removing the produce field heat. This method is very effective but can dehydrate the produce.

Forced-air cooling

This method uses pressure differential across the pallet to draw air through them. This method is the most versatile and widely used of all the methods. Traditionally, tarped cooling tunnels are used to precool variety of palletized produce. These tunnels require manual loading of pallets in rows then a tarp is laid across the gap between the pallets rows. This process can be tiresome and more often, ineffective which is why cold room suppliers emphasize on forced-air coolers that do not require a tarp. Unlike the tarped cooling tunnels will require one to probe the produce periodically, and check if the precooling process is complete, these coolers are designed to automate the appropriate amount of cooling time on the produce.

from Home Improvment http://notelocreesnitu.tumblr.com/post/156355618834