Freezing is usually used to pre-dry
fruit and vegetable, aim to increase the drying speed and improve final product
quality. In the freezing process, moisture will turn into ice crystals and then
destroy cell structure to become multi-holes, promote moisture transfer.
Freezing is one important pre-processing
step in the vacuum frying chips process. Almost all raw materials need freezing
before vacuum frying, to increase dehydration rate and keep chips quality.
Why is banana exception?
Before the explanation, let me introduce
banana chips vacuum frying production process. The first step is separating
bananas one by one from the stalks, and then putting them into bubble washing
line to removing the dust on the banana peel. The second step is manual peeling
banana in shortest time. The third step is cutting the banana into slices shape
and then frying directly with the vacuum frying machine.
From the above introduction, we can
discover that the process time is very short and simple after peeling, aim to
shorten the contact time of banana and air, avoid banana oxidation and browning
reaction as much as possible. But, the freezing process will add the contact
time, influence quality and color. The more important cause is the final banana
chips have higher oil content compared with those chips without freezing.
Thus some clients don’t freeze banana
before vacuum frying.
