Spherulitic Crystallization of L-Tryptophan: Characterization, Growth Kinetics, and Mechanism

Abstract

L-Tryptophan was successfully crystallized in the form of spherulites by introducing trace amounts of gelatin into the crystallization solution. The physicochemical properties of L-tryptophan products were significantly improved by using this polymer-induced spherulitic growth strategy. This newly developed polymer-induced spherulitic growth strategy provides another choice for controlling the size distribution of particles. Furthermore, the formation and growth of these spherulites under different conditions was monitored in situ by using particle vision measurement and microscopy. It was found that the morphologies of spherulites could be influenced by the additives, the crystallization temperature, and the initial concentration of L-tryptophan. The influence of temperature on the growth rate of spherulites was investigated. It was found that the growth rate is constant at given temperatures. A population-based empirical model was developed and used to explain the spherulitic growth of L-tryptophan sphe...