tocopherols & tocotrienols
Vitamin E describes a family of eight antioxidants: four tocopherols and four tocotrienols. Alpha-tocopherol is the form that is preferentially absorbed and accumulated in your body. Vitamin E protects cells against damage and is important for growth. Although vitamin E is sensitive to light, heat and oxygen there appears to be minimal loss with cooking. Because it is fat soluble there is little leaching into cooking water.
Try to cook with a just single layer of vegetables in your pan at a time. Overcrowding prevents even cooking and you run the risk of ending up with mushy veg on the bottom.