Blanching fruits and vegetables

Why do we have to blanch produce before canning or freezing?

What is blanching and why do we have to do it when freezing or canning produce? That is a question I often get asked when I am teaching a food preservation class. It is all about science and what it has taught us in preserving food safely.

Blanching is when you boil your produce in one gallon of water per pound of produce. The water is brought back up to boiling and timed according to the specific produce you are blanching. To make sure you are blanching for the correct amount of time check the USDA food preservation website of So Easy to Preserve sixth edition for correct times. Blanching is a method used to stop the action of enzymes in the produce. If blanching is not done, the flavor, color and texture of the produce are affected. Blanching also benefits the produce by cleaning off the surface dirt from the product.

After blanching the produce, the cooking action needs to be stopped. This is done by placing the produce in cold water or ice water unless the recipe states otherwise. Continue on, following safe food preservation practices stated by USDA guidelines. Michigan State University Extension always recommends using an approved science based recipe for safe food preservation.

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