Hydroxyproline Content in Several Foods

Abstract

A simple colorimetric method was used to determine hydroxyproline in food. Dried foods were hydrolyzed in 6N HCl at 110°C for 18hr, and then hydroxyproline in the hydrolyzate was determined after neutralization. Hydroxyproline content in many kinds of foods was determined. In general, animal tissues contained more hydroxyproline than vegetable tissues. Moreover, animal tissues showed higher value of hydroxyproline per protein than vegetable tissues. Significant quantities of hydroxyproline-containing proteins were extracted from animal tissues with 0.6N HCl, but those of vegetable tissues were small amounts.