The answer to this question is difficult to pin to one food or another. The reason for this is that it depends on the food and the nutrient and how the product is prepared. For example: frozen blueberries have higher levels of ascorbic acid than fresh varieties, but the same amount of riboflavin as fresh in studies. For more details, review these studies: 1) Krebs-Smith, et al., 2) Frozen Food Foundation, 3) Rickman, et al., 4) Rickman, et al., 5) Bouzari, et al., and 6) Bouzari, et al. What we know is that frozen fruits and vegetables are as healthy as fresh. The best thing to do is eat a variety of fresh, frozen, canned, dried, and 100% juice to achieve ideal nutrition.