Food put in a blender, or otherwise chopped or cut, keeps its nutritional value. Food can lose some nutritional value when it is cooked, as the chemical composition of the food changes slightly.
Food blended is still the same food and retains its nutrition. However, that nutrition could be diluted if water or other liquid is added to enable the process then poured off later.
In general yes, the only thing that could be affected is that a blender could break food down and make it easier to digest. This sends it through your digestive system quicker and some nutrients might not be extracted from your food. In the end though, this is minor.
Yes. The blender changes the texture of the food but there is not chemical process involved that would destroy its nutritional value. That's why health-food diets recommend blending raw fruits and vegetables.
Food put in a blender should retain its nutrition as long as it's not heated or if by peeling it you take that away. As much as possible keep it in it's original form. If the peelings would provide fiber but not other nutrients this would be a loss but could be fixed.
