Photothermal denaturation of egg white by pulsed holmium laser

摘要

Heat denaturation of egg white is usually followed by polymerization or gelatin of the denatured components, primarily albumin, and is associated with manifestation of a distinct increase in scattering or whitening of the egg white. In this study the effect pulsed laser coagulation of egg white was studied using a CTH:YAG laser delivered through a 600 $mu@m diameter fiber into a cuvette filled with raw egg white. The dynamics of laser induced photothermal denaturation of egg white was observed by monitoring the increase of light scattering by time resolved video imaging. Two distinct laser induced processes were observed. At higher radiant exposure ($GRT 30 - 40 J/cm$+2$/) the egg whites was rapidly heated above the water vapor transition temperature and a cavitation bubble was formed. Below threshold for bubble formation a bullet-like zone of whitened egg-white is formed at the top of the fiber.