Frozen blueberries are an example of quick frozen foods that actually retain their nutritional value for longer, as they are preserved at their peak, not before. Since development of a technology known as the individually quick-frozen (IQF) method, foods can be frozen when they are at their peak of freshness. Blueberries are a “superfood” packed with antioxidants, vitamins and minerals so are excellent when detoxing through this superfood smoothie.