Phytochemical Composition of the Fruits and Leaves of Raspberries (Rubus idaeus L.)—Conventional vs. Organic and Those Wild Grown
Marta Kotuła, Joanna Kapusta‐Duch, Sylwester Smoleń, Ivo Doskočil
Abstract
Nutrition is an influential determinant of the risk of present-day metabolic diseases. Raspberries (Rubus idaeus L.) are extraordinary berries with a high nutritional and bioactive component complex. They have a number of major essential minerals and trace elements as well as dietary fibre and other important constituents. This study aimed to analyse and compare raspberry fruits and leaves originated from organic versus conventional agricultural practices and wild grown for the contents of basic composition (water, crude fat, total protein, ash, digestible carbohydrates and dietary fibre) and selected minerals (calcium, iron, potassium, magnesium, sodium, phosphorus, sulphur, selenium, barium, lithium, and beryl) as well as selected antioxidant properties (total polyphenols, total carotenoids, anthocyanin content, and antioxidant activity by methods of ABTS and FRAP). This study was carried out regardless of climatic and agro-technical factors and was of a more consumer-oriented nature, in order to recognize the diversity of raspberry fruits and leaves from more or less monitored crops. The basic composition, mineral content and selected antioxidative properties of raspberry fruits and leaves are fundamentally different. Raspberry fruits have a lower content of protein and ash, and higher levels of dietary fibre and carbohydrates in comparison to fruits. The biggest difference is the amount of protein, whose content in leaves is two to three times higher versus fruits. Raspberry leaves have been found to have a higher mineral content than raspberry fruits and were characterized by up to five times the amount of total polyphenols, with respect to raspberry fruit, regardless of source. The content of total carotenoids was found in some cases to be 100 times higher in raspberry leaves, in comparison to fruit, regardless of origin. It has not been definitely identified, both for raspberry fruits and leaves, which method of growing is the most advantageous in terms of levels of basic nutrients, selected minerals and antioxidant properties.