Investigation on biocatalytic properties of a peroxidase-active homogenate from onion solid wastes: An insight into quercetin oxidation mechanism

Osman, Ali; Makris, Dimitris P.; Kefalas, Panagiotis

doi:10.1016/j.procbio.2008.04.003

Cited by 46 publications

(35 citation statements)

References 48 publications

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“…In a similar fashion, compound (9) was identifi ed as a quercetin dimer (LY et al, 2005;GÜLŞEN et al, 2007a). Compounds (1) and (9) have been demonstrated to derive from quercetin through oxidative cleavage by onion peroxidase (OSMAN et al, 2008). Further, compounds (2) and (9) have been generated using bio-mimetic, metal-catalysed oxidation reactions (GÜLŞEN et al, 2007a, b).…”

Section: Polyphenolic Compositionmentioning

confidence: 99%

Kinetic modelling for polyphenol extraction from onion (Allium cepa) solid wastes using acidified water/ethanol mixture

Makris¹,

Kefalas²

2015

Acta Alimentaria

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Previous reports highlighted the onion solid wastes as abundant, residual material that might contain a signifi cant load of antioxidant polyphenols. Although there have been studies pertaining to polyphenol recovery from onion wastes, the effect of temperature has not been adequately addressed. In this line, this study was undertaken with the aim of establishing a correlation between the extraction yield in total polyphenols and the extraction temperature, using acidifi ed aqueous ethanol as the solvent system. Extraction of polyphenols from onion solid wastes was found to obey 2 nd -order kinetics. On such a basis, the yield in total polyphenols at saturation could be very effectively determined and correlated with temperature using non-linear regression. The results indicated that the extraction yield at saturation is highly correlated with temperature, following a quadratic function. The extract obtained at optimal temperature (40 °C) had a total polyphenol yield of 21.10 mg gallic acid equivalents per gram of dry weight, and it was further analysed by liquid chromatography-mass spectroscopy to characterise its major constituents. The polyphenols detected were quercetin glucosides, as well as quercetin oxidation derivatives, including certain degradation products and dimers. The outcome of this study outlined that temperatures above 40 °C are rather not favourable for polyphenol extraction from onion solid wastes, as suggested by the model established through kinetics. The extract obtained under optimal conditions contained peculiar polyphenolic composition, not encountered in any other food processing residue.

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Section: Polyphenolic Compositionmentioning

confidence: 99%

Kinetic modelling for polyphenol extraction from onion (Allium cepa) solid wastes using acidified water/ethanol mixture

Makris¹,

Kefalas²

2015

Acta Alimentaria

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“…On the other hand, the detection of products arising from quercetin oxidation evidenced the activity of POD. Indeed, the detection of PA and BD, which are known to derive from POD-mediated quercetin oxidation (Osman et al 2008;Takahama and Hirota 2000), is a sound argument for POD activity upon quercetin. The fact that POD was found active during 48 h corroborates this assumption.…”

Section: Resultsmentioning

confidence: 99%

“…Following this, quercetin is in turn acted upon by POD to produce PA and BD. Because other oxidation products that have been previously identified (Osman et al 2008) were not detected, it can be presumed that the pathway proposed might be favourable under the conditions employed, which represent conditions that could be encountered in both domestic and industrial processing of onions.…”

Section: Resultsmentioning

confidence: 99%

Stability and transformation of major flavonols in onion (Allium cepa) solid wastes

Khiari

Makris

2010

J Food Sci Technol

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Onion solid wastes were analysed using HPLC and LC / MS and the major polyphenols detected were quercetin, quercetin 4′-O-glucoside, accompanied by protocatechuic acid and a benzofuranone derivative. The latter two compounds have been demonstrated as some of the degradation products that might arise as a result of peroxidase-mediated decomposition of quercetin. These four substances, along with two principal enzymes implicated in flavonols breakdown, β-glycosidase and peroxidise, were monitored throughout an examination period of 48 h, in ground onion solid waste. The determinations showed that quercetin 4′-O-glucoside content increased by 13.3%, while quercetin, benzofuranone derivative and protocatechuic acid contents increased by 68.6, 37.5 and 58.4%, respectively. β-Glycosidase activity exhibited fluctuations and increased by 38.2%, whereas the POD showed a constant increasing trend, leading in 21.7% higher activity. On such a ground, a hypothesis was set up to explain transformations of flavonols.

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“…The investigation of a crude onion POD showed that quercetin oxidation might be favored at pH 8 (Takahama and Hirota 2000), but this result was contrasted by more recent data indicating that quercetin oxidation rate peaks at pH 4 (Osman et al 2008). The pH optimum found for CGA is thus in line with this outcome, but also with the one found for hydrocaffeic acid and FA (El Agha et al 2008a, b).…”

Section: Effect Of Ph and Temperaturementioning

confidence: 89%

Chlorogenic Acid Oxidation by a Crude Peroxidase Preparation: Biocatalytic Characteristics and Oxidation Products

Osman

Agha

Makris

et al. 2009

Food Bioprocess Technol

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Investigation on biocatalytic properties of a peroxidase-active homogenate from onion solid wastes: An insight into quercetin oxidation mechanism

Cited by 46 publications

References 48 publications

Kinetic modelling for polyphenol extraction from onion (Allium cepa) solid wastes using acidified water/ethanol mixture

Kinetic modelling for polyphenol extraction from onion (Allium cepa) solid wastes using acidified water/ethanol mixture

Stability and transformation of major flavonols in onion (Allium cepa) solid wastes

Chlorogenic Acid Oxidation by a Crude Peroxidase Preparation: Biocatalytic Characteristics and Oxidation Products

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