Decolorization of oily browning compounds from Koshu wine by products formed by gamma-radiolysis of water and ethanol

An oily browning fraction, F2, isolated from baking Koshu wine, was dissolved in water or aqueous ethanol solution. The sample solutions were adjusted to pH 7.0, saturated with N2, N2O or O2, and then irradiated with 0.2 to 1.0 Mrad of 60Co gamma radiation. Decolorization of the sample solutions progressed with increasing radiation dose. The effects of the products formed by gamma-radiolysis of water and ethanol on the decolorization of F2 were investigated. Decolorization of F2 was never of hardly affected by addition or introduction of H2O2, H2, and OH formed by radiolysis of water; acetaldehyde; and ethanol itself and pre-irradiated ethanol. F2 was decolorized, however, by reducing radicals, esub(aq)- and H, formed by radiolysis of water and ethanol radical formed by reaction of ethanol with OH in the absence of O2, and by O2-formed by reaction of the reducing radicals with O2 in the presence of O2. (auth.)