Carbon-centered radicals in soy protein products


The free-radical content of typical powdered soy protein products ranged from 2.96 × 1014 to 4.10 × 1015 spins per gram. These levels are about 14-to 100-times greater than other food protein sources. The majority of these free radicals appear to be formed after the soy protein product is manufactured, and during storage of the 'dry' powder exposed to oxygen. The radicals react to form non-radical species once the soy protein is hydrated with water, except in solutions of erythorbate or cysteine that result in elevated levels of radicals. If the water-hydrated proteins are subsequently dried and again stored exposed to oxygen, the levels of radicals will gradually increase back to levels that existed prior to hydration. Based on the peak shape, g-value and power saturation characteristics obtained with electron paramagnetic resonance spectroscopy, the free radicals in soy protein are predominately comprised of carbon-centered radicals. © 2010 American Chemical Society.

Publication Title

ACS Symposium Series

This document is currently not available here.