Kumquat Fruits as an Important Source of Food Ingredients and Utility Compounds

The kumquat tree occurs in practically all countries of the subtropical zone. Kumquat fruits with a characteristic shape, size, colour and taste are the smallest of edible citrus and the only ones that can be eaten as a whole with the peel. Those fruits are rich in fiber, carotenoids, vitamins and minerals. The most important components are polyphenols showing antioxidant properties, in particular flavonoids of which the one characteristic is phloretin. The essential oils extracted from them are rich in numerous terpenoids, responsible for fragrance and aroma. An extensive literature review was carried out to collect data on the chemical composition of kumquat fruit and other selected parts of the plant. These data, depending on the variety, origin, part of the plant and method of obtaining were compiled and presented in the appropriate tables and figures. The structures of the most important components were also presented. Due to their nutritional properties and biological activity (antioxidant, antimicrobial, antitumor etc.) these components are potential sources of ingredients for foods, phytopharmaceuticals and cosmetics.