%0 Journal Article
%T Evaluating the Effect of Gamma Radiation on the Total Phenolic Content, Flavonoids, and Antioxidant Activity of Dried Pleurotus ostreatus ((Jacq. ex. Fr) Kummer) Stored in Packaging Materials
%A Nii Korley Kortei
%A George Tawia Odamtten
%A Mary Obodai
%A Victoria Appiah
%A Felicia Akuamoa
%A Afua Kobi Adu-Bobi
%A Sylvester Nana Yao Annan
%A Jonathan Nii Okai Armah
%A Stanley Akwesi Acquah
%J Advances in Pharmaceutics
%D 2014
%R 10.1155/2014/262807
%X Dried Pleurotus ostreatus mushrooms stored in polythene and polypropylene packs were exposed to gamma radiation from a cobalt-60 source at doses of 0, 0.5, 1, 1.5, and 2ˋkGy at a dose rate of 1.7ˋkGy/hr and stored for a period of 1 month. Total phenolic contents, flavonoids, and free radical scavenging activity DPPH (2,2∩-diphenyl-1-picrylhydrazyl) were determined using aqueous, ethanol, and methanol extracts by Folin-Ciocaultaeu method as a source of potential natural antioxidants. Total phenol content ranged 0.56 ㊣ 0.01每10.96 ㊣ 1.7ˋmg/GAE, flavonoids ranged 1.64 ㊣ 0.05每8.92 ㊣ 0.6ˋmg/QE, DPPH radical scavenging activity also ranged 7.02 ㊣ 0.10每13.03 ㊣ 0.04%, and IC50 values also ranged 0.08每0.16ˋmg/mL. Statistical differences (P < 0.05) were recorded for the extracts and the treatment doses of mushrooms stored in polythene and polypropylene packs. A significant linear correlation was confirmed between values for the total phenolic content and antioxidant activity of mushroom extracts. The high contents of phenolic compounds indicated that these compounds contribute to high antioxidant activity. Pleurotus ostreatus can be regarded as a promising candidate for natural mushroom sources of antioxidants with high value. The use of low dose gamma radiation by the local food industry could improve the hygienic quality, extend shelf-life, and preserve nutrients and antinutrients. 1. Introduction Phenolic compounds are secondary metabolites that are derivatives of the pentose phosphate, shikimate, and phenylpropanoid pathways in living organisms [1每3]. They act in defense against pathogens, animal mycophage, or fungivore aggression and as response to various abiotic stress conditions, such as rainfall and ultraviolet radiation [4]. Polyphenols have protective activity which has been previously attributed to free radical scavenging, metal chelating properties, capability of inhibiting or reducing different enzymes, such as telomerase [5], cyclooxygenase [6, 7], or lipoxygenase [8, 9], and then most importantly as antioxidant compounds with the ability to trap free radicals and thus inhibit the oxidative mechanisms. However, in more recent years, they play roles such as interacting with signal transduction pathways and cell receptors [10每12]. Naturally occurring antioxidants can be found in whole grains, fruits, vegetables, teas, spices, and herbs. Mushrooms have also been reported as living organisms with antioxidant activity which is correlated with their phenolic and polysaccharide compounds [13每15]. Their global economic value is now incredible, and the
%U http://www.hindawi.com/journals/ap/2014/262807/