Relationship analysis between flavonoids structure and subcritical water extraction (SWE)

• Published in: Food chemistry Vol. 143; pp. 147 - 155
• Main Authors: Ko, Min-Jung, Cheigh, Chan-Ick, Chung, Myong-Soo
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 15.01.2014; Elsevier
• Subjects: Biological and medical sciences; Chemical Fractionation - methods; Chemical structure; Flavonoids; Flavonoids - chemistry; Flavonoids - isolation & purification; Food toxicology; Hot Temperature; Medical sciences; Molecular Structure; Optimum conditions; Plant Extracts - chemistry; Plant Extracts - isolation & purification; Plants - chemistry; Solubility; Subcritical water extraction; Toxicology; Water - chemistry; Flavonoids; Optimum conditions; Subcritical water extraction; Chemical structure; Water; Antioxidant; Flavonoid; Micronutrient; Polyphenol; Plant origin; Phenols; Extraction; Proanthocyanidin
• ISSN: 0308-8146; 1873-7072
• DOI: 10.1016/j.foodchem.2013.07.104

•SWE of non-polar flavonoids by temperature-dependent dielectric constant.•Determination of optimum SWE conditions for thirteen flavonoids from eight plants.•SWE selectivity based on the chemical structure of flavonoids.•Analysis of factors affecting the optimum SWE of flavonoids. Subcritical water (about 10MPa) is an excellent solvent for extracting non-polar flavonoids by varying the temperature-dependent dielectric constant. This study determined the optimum conditions for subcritical water extraction (SWE), such as the time and temperature, for extracting flavonoids from eight plants, and their dependence on the chemical structure of flavonoids (polarity of side chains and the presence of sugar, and double bonds). Flavonoids having an OH side chain (quercetin at 170°C/10min) were optimally extracted at lower temperatures than O–CH3 (isorhamnetin at 190°C/15min) and H (kaempferol at 190°C/15min) side chains. The optimal temperatures of the glycoside forms including sugar, such as quercitrin (110°C/5min), spiraeoside (150°C/15min), and isoquercitrin (150°C/15min), were lower than of the less-polar aglycones (170°C/10min and 190°C/15min). Apigenin, having double bonds, was extracted well at a higher temperature (190°C/15min) than naringenin (170°C/15min) in SWE.