|Analysis of Food-based Antioxidants|
|Elderberries provide approximately 750 mg/100 g of cyanidin [cf. blueberries with 15 mg]. They also provide 42 mg quercetin.||Aubergines have B vitamins and three essential minerals; potassium, iron and zinc.||Blueberries are rich in anthocyanidins with : 50 mg malvidin, 30 mg delphinidin, 15 mg cyanidin and 12 mg petunidin per 100 g.|
|Recent analytical methods|
Uses cerium (IV) sulphate in dil. sulphuric acid at room temperature, with pH and oxidant concentration adjusted "such that only antioxidants and not other organic compounds would be oxidised. The method using quercetin and gallic acid standards, was applied to 8 other antioxidants, and was cross-referenced to ABTS and CUPRAC. The results were expressed as TEAC coefficients.
D. Ozyurt, B. Demirata and R. Apak, Talanta, 71, (3), 1155-1166, 2007.
[Permission to reproduce these data granted by Elsevier]
4. A new biamperometric elecrochemical method
Uses Flow injection analysis, interdigitated array microelectrodes and an ABTS cation/ABTS redox couple in phosphate buffer at pH 7.40. The radical cation was enzymatically produced by immobilised peroxidase in a tubular flow-through reactor, giving the advantage over previous spectrometric methods, of instant reaction with freshly generated cations. The new method correlates well with previous spectrophotometric methods.
S. Milardovic et al., Talanta 71, (1), 213-220, 2007.
[Permission to reproduce sought from Elsevier].
5. An update to the CUPRAC method.
The cupric ion reducing antioxidant capacity assay using copper (II)-neocuproine reagent as the chromogenic agent is described. The preparation procedures are adapted for slowly reacting antioxidants, etc., and flavanoid glycosides were hydrolysed to the aglycone. Results were compared to ABTS/persulphate and Folin methods.
R. Apak et al., Microchim. Acta, 21 May 2007.
6. Antioxidant capacity and various other bioactivities of Acai.
In a textbook experiment, using seven assays to measure the bioactivity of the freeze-dried Acai fruit, R.L. Prior's team reported on the antioxidant properties of Acai against: superoxide anions, peroxyl radicals, peroxynitrite anions and hydroxyl radicals. Also it proved that acai antioxidants can enter human cells in in vitro experiments.
A.G. Schauss et al., J. Agric. Food Chem. 54, 8604-8610, 2006.
back to >>>> Chemical analysis
back to >>>> Site map