ABSTRACT
LC-ESI-MS analysis was used for identification of phenolic compounds in the methanolic extracts of commercially available dried oregano, sage and thyme. Rosmarinic acid, apigenin-glucuronide, luteolin-glucuronide, as well as quinic acid were present in all three spices. Whereas in thyme and sage only derivatives from flavonoid compounds were identified, in oregano also the aglycons eriodictyol, naringenin, hispidulin, apigenin and luteolin could be found. Some constituents, especially glucosides and glucuronides, were observed for the first time in the methanol extracts of these spices. To ascertain an irradiation influence (dose: 10kGy) the MS peak area counts of twenty constituents, among them 10 glycosides/glucuronides, were compared. Although the majority of those compounds exhibited a slight decrease with irradiation, the changes were not significant.
ABSTRACT
Fresh mushrooms ( Agaricus bisporus ) were irradiated at doses of 1, 3, and 5 kGy to assess the effect of gamma-irradiation on the major aromatic compounds agaritine (beta-N-(gamma-L-(+)-glutamyl)-4-(hydroxymethyl)phenylhydrazine) and GHB (gamma-glutaminyl-4-hydroxybenzene) as well as on the total phenolic content and antioxidant capacity. Up to 3 kGy, agaritine was not affected. At 5 kGy, a significant reduction (p = 0.05) from 1.54 (0 kGy) to 1.35 g/kg dry weight (DW) was observed. gamma-Glutaminyl-4-hydroxybenzene decreased by 22% at 1 kGy and by 31% at 5 kGy. Additionally, agaritine standard solutions at concentrations of 10(-4) and 5 x 10(-5) mol/L were irradiated to compare the effect on agaritine content in aqueous solutions and in the sample matrix. A rapid decay was observed, 50% at 750 Gy (10(-4) mol/L) and 400 Gy (5 x 10(-5) mol/L). The total phenolic content and antioxidant capacity were not significantly (p = 0.05) influenced by irradiation.
