I’ve read in a lot of places that steaming vegetables helps them retain more of their nutritional content than boiling or blanching them does. Does anyone have solid facts about how true this is? I’m sort of looking for quantititative information, like “steaming broccoli loses 40% less vitamin content than boiling” or whatever. I was pondering this earlier when sitting down to a side dish of creamed spinach. I love the stuff, and I know spinach is full of folic acid and vitamin A and probably some other stuff, but does it actually retain any of that nutritional content after having been steamed and wilted and stirred with cream?
On a related note, how nutritional are fresh veggies compared to frozen, compared to canned? We buy fresh when possible, but I’m wondering if it’s really that much better than frozen, from a nutritional standpoint.
Boiling vegetables will result in the loss of Vitamin C and the B vitamins. Steaming is the best way to cook vegetables - and if you’re going to boil them (either in a pot or in the microwave) you should do it for the shortest time possible to reduce the amount of nutrients that leach into the water.
Water soluble will be lost much more than fat soluble vitamins, and some other nutrients (e.g. antioxidants) can be lost as well.
Frozen vegetables are generally prepared soon after harvest, so they’re comparable to fresh vegetables in terms of nutrition. Prepared/frozen vegetables that were blanched (boiled in water) before being frozen will also have lost some nutrients.
Cooking tips (from the third link on the list below)
I steam my veggies in parchment paper and also drink the liquid that comes out of them in the process. You can buy the paper in the supermarket. You just put the veggies on the paper and fold it both ways to retain the liquid when they cook. They also seem to retain more of their flavor.
Frozen veggies can have more nutrition than fresh if the so-called fresh vegetables are grown in depleted soil, picked before mature, processed, and travel distances before they are available for sale. The best of course is home grown.
Whichever site that comes from, ignore it. Vitamin C is heat labile. It isn’t lost through leaching into the water, it’s chemically destroyed by the heat. Since water used for steaming has been boiled there will be almost no vitamin C in it. Using the water for sauces won’t put it back.
One thing to keep in mind is that the human digestive system does not break down cellulose very well, but cooking does, so whatever vitamins remain in cooked vegetables are generally more available than those in raw vegetables.
Yes, Ultrafilter, I’ve heard that stewed tomatoes are great because the stewing “breaks down” the tomato a certain degree so that the human body can “absorb” more of the nutrients.