Lettuce ! If you ever figured a way to preserve it, you'd make a lot of home gardeners VERY happy !
Lettuce will keep in a refrigerator for a while, but you cannot freeze or dehydrate it. I know of no process to store lettuce !
Lettuce
The vegetable is the cucumber.
watermelon
Processed Vegetable Growers' Association was created in 1969.
The first commercially available frozen vegetable was spinach or peas.
I have never seen eggplant in a processed form.
Lettuce
the potato
No Pizza is not a vegetable, a pizza does not grow in soil. A pizza may have vegetables on it but you cannot say it is a vegetable.
Frozen vegetables are processed by blanching them in hot water or steam to stop enzyme activity that causes spoilage. They are then quickly frozen to lock in their freshness and nutritional value.
Tables
It depends on how long it is frozen