| Abstract [eng] |
Strawberries are one of the most popular berries, usually used fresh or processed into various products: such as jams, puress, wine and juice. After juice processing a large amount of pomaceare removed as a waist. Aproximatelly about 4 to 11 % after juice production remains strawberries pomace [19, 20]. Strawberries pomace is known as a source of bioactive compounds, which could be used as an ingredients for functional food [6]. The aim of Master‘s project is to extract bioactive compounds from strawberries (Fragaria × ananassa) pomace using different extraction methods, such as multi-level extraction, accelerated solvent extraction (ASE) and supercritical carbon dioxide extraction. In addition Response Surface Methodology was used for the optimization of SFE parameters, pressure, time and temperature. high pressure extraction, ti obtain maximum yield. Examine antioxidant properties, phenolic and aromatic compounds of obtained pomace fractions/extract after extraction. Evaluate poximate analysis of obatined pomace. Proximate analysis showed, that dried strawberry pomace contain: moisture – 5,60 %, lipids – 12,03 %, proteins – 13,27 %, crude fiber – 32,5 % and minerals – 5,33 %. The highest yield were obtained after multistage pressurized extraction with ethanol (33,85 g/100 g DW). The maximum yield of CO2 extract obtained using 40 MPa pressure, 70 °C temperature and 210 min dynamic time of extraction. Antioxidant activity was determined by using the DPPH and ABTS∙+ radical cation methods and by applying ORAC method – oxygen radical absorbance capacity was determinated. The Folin Ciocalteu‘s method was used to measured the total phenolic compounds. The extracts were subjected to the traditional procedure and to solid fraction – QUENCHER procedure. Extracts obtained by pressurized liquid extraction with ethanol showed the highest antioxidant capacity and total phenolic content. Total phenolic content of pomace residue after variuos extractions were 3,3–20 lower than extracts. Antioxidant capacity of pomace residue were 1–2,4 lower than extracts. In this study were identified and quantified triacylglycerols, anthocyanins and other phenolic compounds in different extracts by ultra efficient liquid chromatography – mass spectrometry. The composition of fatty acids and volatile compounds were analyzed by variuos gas chromatography methods. The major anthocyanin found in all analyszed extracts - pelargonidin 3-glucoside, the main phenolic acids and flavonoids were: ellagic, p-coumaric acids quercetin 3-glucuronide and tiliroside. The polyunsaturated linoleic fatty acid was predominant in the supercritical CO2 extract. The major identified aroma compounds in strawberries pomace and CO2 extracts were: decalactone, ethyl hexadecanoate, -dodecalatone, methyl linoleate, hexanal, 1-hexanol and 1penten-3-ol. |
