Carbon dioxide-protein interaction in a gas-solid phase.

Abstract

In the course of developing the packaging of protein foods under the carbon dioxide atmosphere, various proteins in a solid state were found to adsorb carbon dioxide gas gradually. The results obtained by the Warburg manometry indicated that 100-1000 mul of carbon dioxide gas was adsorbed at 25 degrees C for 24 hr by gram of purified proteins, dried protein foods and other proteinous materials such as the rabbit hair and raw silk when they were placed in the high partial pressure of carbon dioxide gas. Casein, gelatin and raw silk were revealed to be the better adsorbents comparing with egg albumin, hemoglobin, gluten and others tested in this experiment. This adsorption was found to be almost specific to carbon dioxide gas. Amount of carbon dioxide gas adsorbed by casein and gelatin depended on the moisture content of them. The lower the moisture is, the greater the adsorption amount of carbon dioxide gas increase. Peptones and partial hydrolyzates of gelatin also showed the adsorbability. Oligo-peptides, amino acids and amines were examined too. Among these, L-lysine (free base), L-arginine (free base), histamine and tyramine adsorbed a large amount of carbon dioxide gas while others failed to do so. Some differences, however, were observed between temperature dependence and reversibility of the carbon dioxide gas adsorption by proteins and those by amines and amino acids (free bases). The mode of interaction between carbon dioxide and protein in a gas-solid phase was discussed comparing with the results obtained in a gas-liquid phase. Large contribution of physical adsorption and less contribution of chemical reaction or chemisorption were assumed in the mode of the carbon dioxide-protein interaction.