Crisp, fresh, brightly colored raw vegetables provide a number of health benefits over cooked vegetables. They contain more nutrients, vitamins and minerals than cooked. The fiber content is higher in raw vegetables than cooked. However raw vegetables can be more difficult to digest. Starches are much harder to digest when raw.
Frozen vegetables are not considered raw vegetables. The water in the cell structure of the vegetable freezes. Frozen water expands and bursts the cell structure of the plant. Additionally most frozen vegetables have been blanched before being frozen. Taste and nutritional benefits can differ greatly between fresh and frozen, which method to use is a matter of preference.
All veggies must be thoroughly cleaned and scrubbed, but this is especially important for raw veggies since all of the bacteria on them may not be killed by heat during the cooking process. Thorough cleaning also removes pesticide residue.
The vegetables are not subjected to any heat, drying, freezing or other processes that can destroy the cell structure of the plant or root. Nearly all vegetables can be consumed raw. However some vegetables are easier to digest such as broccoli or taste better when partially or fully cooked.
Blanching to Freezing
Vegetables are plunged in vigorously boiling water for one minute and then immersed in an ice bath to stop the cooking. Blanching softens the outer skin and cells of the veggie without cooking the inner portion. Blanching kills bacteria and viruses lingering on the surface of the veggie or in hard to clean places such as inner crevices. Blanching improves the flavor and texture of some vegetables.
The vegetables are subjected to steam for a period of time ranging from a few minutes to 30 minutes. Water is brought to a boil in a pot. A steaming basket, colander or strainer is placed over the boiling water but not touching the water. The vegetables are placed in the basket and covered tightly. Veggies are not placed in the water so nutrients are not washed away. Lightly steamed veggies retain quite a few characteristics of raw veggies and in fact the inner portions may still be raw.
Vegetables are submerged in cold water. The water is brought to a boil and vegetables are cooked until soft. Minerals and vitamins can be leached out into the water. Most boiled vegetables are overcooked.
Roasted or Baked
This process subjects the vegetables to very high temperatures in a dry environment. In most cases water in the vegetables at least partially evaporates, the cell structure disintegrates and the sugars and flavors of the vegetables are concentrated.