Supercritical CO2 extraction of valuable lipophilic compounds from pre-fractionated sour cherry pomace and evaluation of their composition and properties

Abstract

Valorisation of fruit processing by-products and waste is an important task for increasing the sustainability of agro-food sector. In this study, pitted sour cherry pomace was mechanically pre-fractionated into the 6 different particle size (>10, 4−10, 3−4, 1−3, 0.8−1, <0.8 mm) fractions (9.71−16.41 % proteins, 5.68−12.16 % fat, 62.55−78.39 % carbohydrates) and subjected to supercritical fluid extraction with CO₂ for the recovery of lipophilic constituents. Extract yield depended on fat content and was from 3.38 % to 8.69 %. Linoleic (38.52−47.11 %) and oleic (21.85−39.03 %) were major fatty acids, while triacylglycerols composed of these acids were major in the extracted oils. The concentrations of tocopherols, carotenoids and phytosterols in the extracts were 116.3−432.0, 1218−2564 and 4294−8449 μg/g. Antioxidant activity values were determined for the extracts and solids of initial dry pomace and its residue after extraction. Folin-Ciocalteu Index (basically similar to total phenolic content, TPC), ABTS^•+-scavenging and oxygen radical absorbance (ORAC) values of extracts were 7.86−8.75 mg of gallic acid equivalents/g, 1.72−6.37 and 35.12−95.49 of mg trolox equivalents/g, respectively. It is the first report on comprehensive characterisation of sour cherry pomace fractions extracted by supercritical CO₂.