Sea buckthorn puree, hawthorn or barberry. Fruit (slightly chilled) clean, change, rinse, drain, toss into a little boiling water and cook for a few minutes. Wipe hot through a colander. Pasteurize in small jars or bottles, e.g.. after ketchup, by 20 min. In winter, these purees can be added to jams and syrups you buy, without adding any sugar or in milkshakes, sweetening them a little to taste.