Why exactly do leafy vegetables turn to mush when frozen uncoooked?
I've heard 2 explanations: because of enzymes that get destroyed when cooking (which is chemical) and because plant cells expand when the water inside freezes, and then the cells burst (which is mechanical). Which one is it really? Or both?
On that note, why does cooking (blanching/sautéing) preserve their texture after freezing and thawing? The fact that it does seems to be an argument against the 'burst cells' explanation, since the cells are still full of water after freezing.
Best Answer
In freezing, it is mostly the bursting of the cell walls as the ice crystals expand.
Much like a water balloon holds its shape when it is intact, but becomes flaccid when punctured, so to the cell walls comprising the vegetable.
See related, for why a similar thing happens when you cook spinach: Why does spinach lose its texture when cooked?
Cooked vegetables are already soft and their metaphorical balloons partially deflated. It is not going to get a lot worse for the freezing. The par cooking is mostly disable enzymes which would change the color of the vegetable to dull olive drab, or negatively affect the flavor.
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The most prominent quality issue when it comes to frozen veggiesWhy do frozen vegetables get soggy?
Freezing ruptures cell walls in the plants since the water in the cells expands as it freezes. So when vegetables thaw, some of that water seeps out.What happens when you freeze raw vegetables?
Freezing is an excellent way to preserve fresh vegetables at home. Freezing does not sterilize food; the extreme cold simply retards growth of microorganisms and slows down changes that affect quality or cause spoilage in food.Can you freeze leafy greens?
Spinach, kale, Swiss chard, beet greens, along with mustard and turnip greens freeze well for year-round enjoyment....Freezing directions- Collard greens blanch for three minutes.
- Other greens for blanch two minutes.
- Very tender spinach leaves blanch for 90 seconds.
What happens if you do not blanch a vegetable before freezing it?
Blanching helps vegetables keep their vibrant colors and retain nutrients, and stops the enzymes that would otherwise lead to spoilage. Freezing vegetables without blanching them first results in faded or dulled coloring, as well as off flavors and textures.Freezing Vegetables: Do You Lose Nutrients?
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