| Abstract [eng] |
Plant raw material is rich in bioactive compounds, which have positive health effects. These compounds can be recovered by using different extraction methods. Processing of cherries for juice production generates large amounts of by-products, which are called pomace. Currently, sour cherry pomace are used very inneficiently, for instance by composting or by producing animal feed. Moreover, large amounts of pomace are discarded as a waste causing environmental polution problems. Considering that sour cherry pomace is a rich source of health benefitial polyphenols including anthocyanins, flavonoids, phenolic acids, there is an urgent need of valorizing sour cherry pomace for the recovery of high added value food grade ingredients. For this purpose, the application of biorefining concept seems to be a preferable approach for developing effective processes for recovery of various valuable substances from sour cherry pomace, which may serve as functional ingredients the high value-added food products. The aim of this work was to develop multistepbiorefining scheme for valorizing cherry pomace as a source of valuable nutrients by using supercritical fluid and pressurized liquid extraction processes. The objectives include evaluation of chemical composition, antioxidant properties and anthocyanins content in different sour cherry pomace fractions. Extracts from sour cherry pomace were isolated by different solvents using tradicional (Soxhlet) and modern (supercritical fluid extraction with carbon dioxide and pressurized liquid extraction) extraction techniques. Pressurized liquid extraction (ethanol/water; 70:30) parameters (temperature and time) were optimized for obtaining the highest yields and proanthocyanidins content by using Central Composite Design and Response Surface Methodology modelling. The sour cherry pomace fractions obtained were evaluated by determining important compositional characteristics and their antioxidant values. Antioxidant potential of extracts was measured by ABTS•+ scavenging, oxygen radical absorbance capacity (ORAC) assays and total phenolic content, which was determined by Folin-Ciocalteu method. Antioxidant capacity of solid substances was evaluated by Quencher method. Fatty acids composition and volatiles compounds of lipophilic extracts were analyzed by gas chromatography and triacylglycerols were determined by ultra high performance liquid chromatography. Total carotenoids of lipophilic extract and proanthocyanidins of hydrophilic extracts determination were evaluated by spectrophotometry. Quantitative and qualitative analysis of anthocyanins was performed by ultra high performance liquid chromatography. |
