The objective of the work was to elucidate the chemical composition of fractions of oil extracts obtained during the supercritical extraction on a semi-industrial scale from strawberry (Fragaria x ananassa Duch.), chokeberry [Aronia melanocarpa (Michx.)], and raspberry (Rubus idaeus L.) seeds from industrial press cake. The oil extracts differed in terms of their content of bioactive components: carotenoids, tocopherols, chlorophylls, and fatty acids. Raspberry seed oil was the richest source of tocopherols (620.1-2166.7 mg kg
21) and a-linolenic acid (above 37%). Chokeberry seed oil had the highest content of linoleic acid (above 70%), and a-tocopherol (166.0-1104.8 mg kg 21 ). Strawberry oil was characterized by the highest content of chlorophylls and a-linolenic acid (above 30%). It was showed that the oil fraction collected at the beginning of extraction is characterized by a high acid value, which requires purification steps to be used for food purposes.
Practical applicationsStrawberry, raspberry, and chokeberry by-products left over from the production of concentrated juice are a valuable source of oils rich in n-3 and n-6 polyunsaturated fatty acids, tocopherols, and carotenoids. The research showed that the fractionation of extracts in the course of supercritical extraction leads to oils with varying amounts of different bioactive compounds, and thus to products with potentially wide applications. Seeds oils have high potential utility as a source of unconventional oil for cosmetic and pharmaceutical sectors and biodiesel. Their targeted utilization may be exploited for economic, environmental and health benefits.
| I N TR ODU C TI ONBerry fruits are seasonal food products which are highly prized by dietitians and nutritionists. They contain dietary fiber as well as multiple vitamins and minerals, thanks to which they have high nutritional value.They are also rich in vitamin C, carotenoids, and polyphenolic compounds (Dimić, Vujasinović, Radočaj, & Pastor, 2012;Pap, Pongr acz, Myllykoski, & Keiski, 2004). Poland is now the largest producer of berry fruits in the European Union, with 2014 crops estimated at over 569,000 tons (Witkowski & Dmochowska, 2015). The short fruiting period severely limits the consumption of raw berries, which has led to the intensification of their processing and broadened the assortment of berry products. It is estimated that in Poland 18% of raspberries, 15-20% of strawberries, and 90% of chokeberries are used for the production of juices and beverages (Cybulska et al., 2013;Nawirska 2007 Nawirska , R oj et al., 2009S ojka, Klimczak, Macierzy nski, & Kołodziejczyk, 2013;S ojka, Kołodziejczyk, & Milala, 2013). The processing of berries into concentrated juices leads to by-products ranging in amount from 2% for raspberries, 4% for strawberries, to 16% for chokeberries (Cybulska et al., 2013;S ojka, Klimczak, et al., 2013;. The resulting press cake contains valuable health-enhancing components and as such should not be squandered (Oomah, Ladet, Godfrey, Liang, & Girard...