Healthiest Ways to Prepare Veggies
Frozen vegetables have to go through a blanching process before they are packaged. Blanching involves dropping the vegetables in boiling water for a short period of time, removing them, and putting them in cold water. This process still exposes the vegetables to heat, so some nutrients are lost in the beginning.
In one study, when vegetables were kept frozen for one year at temperatures of -25°C to -30°C, no vitamin C was lost (normal freezer temperatures are -18°C to -23°C). At temperatures of -20°C to -25°C, 10 percent of vitamin C was lost, and at temperatures above -10°C, 80 percent to 90 percent of vitamin C was lost. When looking at other nutrients, 20 percent of thiamine was lost in broccoli, asparagus, green beans, and peas when stored at -18°C for one year. More sensitive vegetables such as cauliflower and spinach lost up to 50 percent of thiamine over one year.
No matter what method is used, some nutrients will be lost when vegetables are cooked. However, there is still plenty of good "stuff" left in them. When you are staring down that plate of cabbage or when your kids are hiding their peas, take comfort in knowing that vegetables are good for you, no matter how scary they look.