Effects of electron-beam irradiation on chemical and antioxidation parameters of wild Macrolepiota procera dried samples
Conference Paper
Overview
Overview
abstract
Mushrooms are very perishable foods due to their high susceptibility to moisture loss, changes in
color and texture, or microbiological spoilage. Drying is considered as the most appropriate
method to prevent these alterations, but it has some limitations, such as shrinkage, enzymatic and
non-enzymatic browning reactions, and oxidation of lipids and vitamins. Irradiation might
effectively attenuate the undesirable changes caused by drying process, ensuring also higher
shelf-life of mushrooms and their decontamination [I]. In the present work, the combined effects
of electron-beam irradiation (at 0, 0.5, 1 and 6 kGy doses) and storage time (at 0, 6 and 12
months) were evaluated and compared. Macrolepiota procera (Scop.) Singer wild samples were
obtained in Tnis-os-Montes, in the Northeast of Portugal, and dried at 30 •c in an oven.
Subsequently, the samples were divided in four groups: control (non-irradiated, 0 kGy); sample 1
(0.5 kGy); sample 2 (1 kGy) and sample 3 (6 kGy). The irradiation was performed at the lNCTInstitute
of Nuclear Chemistry and Technology (lNCT), in Warsaw, Poland. Moisture, protein,
fat, carbohydrates and ash were determined following standard procedures. Free sugars and
tocopherols were determined by high performance liquid chromatography coupled to a refraction
index detector (HPLC-RI) and a fluorescence detector, respectively; fatty acids were determined
by gas-liquid chromatography with flame ionization detection (GC-FID). Antioxidant activity
was evaluated in the methanolic extracts by in vitro assays measuring DPPH (1,1-diphenyl-2-
picrylhydrazyl) radical scavenging activity, reducing power, inhibition of ~-carotene bleaching
and inhibition oflipid peroxidation using thiobarbituric acid reactive substances (TBARS) assay.
Total phenolics were also determined by the Folin-Ciocalteu assay. All the parameters showed a
decrease tendency with storage time. Trehalose and y-tocopherol were preserved with 1 kGy
dose. Electron-beam irradiation did not impart additional changes to most of the chemical and
antioxidant parameters of M. procera dried samples.
This is a very promising result, since electron-beam irradiation might attenuate most unwanted
changes caused by drying, maintaining its long-term effectiveness.
