Thank you for your wonderful column!
I am a vegetarian and use soy products as my main source of protein. I have read about the nutrient value of soy and the benefits of isoflavones. I have never seen anything written about the effect cooking has on the nutrients in soy products. I use soy flour, soy nuts, and soymilk in making bread and am also an avid fan of TVP and baked tofu.
Please advise if any particular form of soy is more beneficial than others and also the effect cooking might have on these health benefits. Thanks again for all of your helpful information!
It appears as though you know what you should be eating for a healthy vegetarian lifestyle.
The benefits of isoflavones are great! Isoflavones are a type of phytochemical which contain naturally occurring chemicals. The phytochemicals have been noted for preventing and treating cancer and are also a weapon against heart disease.
You asked about which type of soy is best. Although all of them are excellent sources of protein and other minerals such as iron, soy protein isolates are of the highest quality, containing 90% protein. Under new guidelines by the Food and Drug Administration, soy protein isolates received a rating of 1; meaning that its protein quality is right up there with dairy and meat products. Soy protein isolates come from de-hulled soybeans. The oil from the beans is also taken out and what is left is called “defatted flakes.” The protein from the flakes results in the soy protein isolates.
Isolates are a highly digestible source of amino acids, which are the building blocks of protein. Isolates are healthy and are low in fat, calories and cholesterol. You can find isolates in bread, baked goods, cereals, pasta, milkshake base, sauces, and soups.
As far as cooking with soy products go, I could not find a resource which said that cooking destroys the protein in soy products. Cooking (heat or water) doesn’t destroy protein. Heat and acids (vinegar, lemon, wine, Worcestershire and soy sauce) denatures protein and starts breaking it down like stomach acid. Read more about protein.
I did find though, that adding soy products to meat and dairy sources maximizes the effects of soy, but since you are a vegetarian, you don’t use meat and may not use dairy products if you are a vegan. Cooking with soy flour is an added protein boost that also reduces shrinkage, provides structure and appearance by tying up fat and water which keeps the bread from becoming stale. In fried foods, it reduces the amount of fat that is absorbed from the dough.