A green ultrasound-assisted extraction process for the recovery of antioxidant polyphenols and pigments from onion solid wastes using Box-Behnken experimental design and kinetics

作者：Katsampa Photene; Valsamedou Evdokea; Grigorakis Spyros; Makris Dimitris P^*

来源：Industrial Crops and Products, 2015, 77: 535-543.

DOI：10.1016/j.indcrop.2015.09.039

• Antioxidants
• Box-Behnken design
• Glycerol
• Kinetics
• Pigments
• Onion solid wastes
• Polyphenols

Onion solid wastes (OSW) were used as raw material to produce polyphenol- and pigment-enriched extracts with antioxidant activity, using ultrasound-assisted solid-liquid extraction. The extraction medium used was free from conventional volatile organic solvents, and it was composed of water and glycerol. Glycerol concentration (C-gl) and liquid-to-solid ratio (R-L/s) were first optimised employing Box-Behnken experimental design and then extraction efficiency was further assessed through kinetics. The optimal conditions were found to be C-gl = 90% (w/v) and R-L/s = 90 mLg(-1), and under these conditions the extraction of total polyphenols and total pigments was shown to obey first-order kinetics. Maximal effective diffusion (D-e) values were 9.28 x 10(-11) and 13.22 x 10(-11) m(2) s(-1), for total polyphenols and total pigments, respectively, while the corresponding activation energies (E-a) were 31.52 and 12.11 kJ mol(-1). The reducing power (P-R) increased as a response to increasing extraction temperature and the extract obtained at 80 degrees C had P-R value of 490 mu mol ascorbic acid equivalents per g of dry weight. Liquid chromatography-diode array-mass spectrometry analysis of this extract showed that the major polyphenols tentatively identified were quercetin 4'-O-glucoside and quercetin, accompanied by other quercetin glycosides, cyaniding 3-O-glucoside and a series of quercetin degradation and oxidation products.

• 出版日期2015-12-23