Walnuts add nutrition, flavour and crunch to a meal. Walnuts are tasty and are an excellent source of omega-3 essential fatty acids and are also rich in fiber, calories, vitamins and minerals. Walnuts are often added to baked goods such as cookies, cakes etc. black walnut and white walnut are the two types of walnut available. Black walnut has thicker shells that are harder to crack and a much more pungent distinctive flavor. The White walnut features a sweeter and oilier taste. Walnuts are more perishable than other nuts hence care should be taken in their storage. Unshelled walnuts should preferably be stored in the refrigerator, although as long as you keep them in a cool, dry, dark place they will stay fresh for up to six months.