Store, covered, in the fridge for up to a day. Puree is suitable to freeze, in 1-tablespoon portions in ice-cube trays, covered, for up to a month. If the puree thickens on standing, thin it with a little cooled boiled water. Quinoa, a seed from a South American plant, is packed with protein and is one of the rare foods that contain all eight amino acids. Delicious blueberries are also high in nutrients.