Chemical characterization and extraction optimization of Aronia melanocarpa polyphenols
Author
Martinez Alfaro, Pedro
Term
4. semester
Publication year
2025
Abstract
This thesis investigates the extraction and chemical characterization of polyphenols from Aronia melanocarpa, with a particular focus on anthocyanins due to their antioxidant potential. Multiple extraction methods (Soxhlet, maceration, and ultrasound-assisted extraction) were compared and optimized using water and acidified water (pH 3) as solvents. Process variables such as temperature, extraction time, and ultrasound amplitude were tuned to maximize anthocyanin yield while minimizing degradation. The best conditions were maceration at 80°C for 2 hours (5.64 mg cyanidin-3-O-galactoside/g dry matter) and ultrasound extraction with acidified water at 50% amplitude for 2 hours (9.50 mg/g dry matter). Stability tests indicated that anthocyanins are comparatively stable for 6–8 hours at moderate temperatures. For isolation, Amberlite XAD-7 was applied in a dynamic column setup with two desorbents (ethyl acetate and 70% ethanol), selectively recovering hydroxycinnamic acids and anthocyanins with up to 95% fractionation efficiency. A HPLC-DAD method (325 and 520 nm) was developed and verified to detect phenolic acids and anthocyanins, enabling identification of cyanidin-3-O-galactoside and chlorogenic acid. Colorimetric assays (TPC, TA, TFC, and DPPH) were used to assess total contents and antioxidant activity. Overall, the study presents a practical and sustainable water-based process that combines improved thermal extraction with resin-based purification to valorize Aronia as a source of bioactive polyphenols.
Dette speciale undersøger ekstraktion og kemisk karakterisering af polyfenoler fra Aronia melanocarpa med særligt fokus på anthocyaniner på grund af deres antioxidative potentiale. Flere ekstraktionsmetoder (Soxhlet, maceration og ultralydsassisteret ekstraktion) blev sammenlignet og optimeret ved brug af vand og vand syrnet til pH 3 som opløsningsmidler. Procesparametre som temperatur, ekstraktionstid og ultralydsamplitude blev justeret for at maksimere anthocyaninudbyttet uden nedbrydning. De bedste betingelser var maceration ved 80°C i 2 timer (5,64 mg cyanidin-3-O-galactoside/g tørstof) og ultralyd med syrnet vand ved 50% amplitude i 2 timer (9,50 mg/g tørstof). Stabilitetsforsøg viste, at anthocyaniner er relativt stabile i 6–8 timer ved moderate temperaturer. Til isolation blev Amberlite XAD-7 anvendt i en dynamisk kolonneopsætning med to desorptionsmidler (ethylacetat og 70% ethanol), som selektivt genvandt hydroxycinnaminsyrer og anthocyaniner med op til 95% fraktioneringseffektivitet. En HPLC-DAD-metode (325 og 520 nm) blev udviklet og verificeret til at detektere fenolsyrer og anthocyaniner og muliggjorde identifikation af bl.a. cyanidin-3-O-galactoside og chlorogensyre. Farvemetriske analyser (TPC, TA, TFC og DPPH) blev anvendt til at vurdere totalindhold og antioxidantaktivitet. Samlet set præsenterer studiet en praktisk og bæredygtig vandbaseret proces, der kombinerer forbedret termisk ekstraktion med harpiksbaseret oprensning for at udnytte Aronia som kilde til bioaktive polyfenoler.
[This apstract has been generated with the help of AI directly from the project full text]