Free radicals in red wine, but not in white?

By using Electron Spin Resonance (ESR) spectroscopy, we have detected free radicals in red wine, whether fermented on oak or not, and in white wine only when it has been fermented on oak. These radicals would appear to be associated with the phenolics, because the ESR signal from the residue of red wine treated with polyvinyl polypyrrolidone is reduced by approximately 80%. Any inhibition of lipid oxidation by red wine phenolics in vitro will take place in the presence of these radicals, which have a linewidth of 2.0 +/- 0.1 gauss and a g-value of 2.0038 +/- 0.0001.

Radiation induced EPR centers in foodstuffs and inorganic materials.

EPR investigations of a variety of irradiated materials have provided the potential for useful dosimetry applications. Herbs and spices imported into Australia have been investigated to establish whether or not they have been irradiated. Post-irradiation studies have shown that there is more than one free radical species in most cases which decay rapidly with time. Changes to transition metal ion signals, e.g., Cu2+ or Fe3+, appear to be permanent against further irradiation. Thus if these signals change upon irradiation, the material almost certainly has not previously been irradiated. Power saturation studies of alanine, a favored dosimetry material, suggest two distinguishable types of behavior consistent with the presence of spin-flip transitions. Irradiation of vanadium doped beryl yields stable VO2+ ions which may provide a useful dosimetry material. Dosimetry applications would appear to demand low cost, user friendly, automated EPR spectrometers. A patented option based on a 2.5 GHz microstrip microwave bridge will be described briefly.

Vocal tract shapes of a flautist in performance.

Lateral view x rays of a flautist in performance show that there is no variation in vocal tract shape with pitch, and that the larynx is lowered from the rest position when notes are played.