Electron spin resonance of free radicals in some legumes, cereals and their aqueous solutions under photolysis

Abstract

In this study free radicals produced by u.v. photolysis in some legumes and cereals have been investigated by electron spin resonance (ESR) technique. The ESR spectra of small grains and powdered legumes and cereals samples have been investigated at room temperature before and during photolysis. Before photolysis barley, wheat, rye, oat and lentil samples exhibit the well known spectra of Mn 2+ ions in addition to a central signal of g = 2.0045 which we attributed to the melanin radical. The melanin signal has been observed also more clearly, in the samples of bean, chick-pea and maize shells before photolysis. The melanin signal has been observed during photolysis in wheat, barley, oat, maize, rice, bean, lentil and chick-pea samples at room temperature. Furthermore, it has been observed that the aqueous solutions of all the cereals and legumes samples investigated in this study gave HC̊O and CO - 2 radicals at 123 K under photolysis. It has been shown that HC̊O and CO - 2 radicals originate from the glucose molecules in the carbohydrate chains of these samples.