Polymorphism of l-Glutamic Acid Crystals and Inhibitory Substance for β-Transition in Beet Molasses

Abstract

Polymorphism exists in L-glutamic acid crystals where the α-form is a coarse pyramidal crystal, while the β-crystal usually has shapes like needles or leaflets with a high moisture content. A method to obtain good α-crystals stably was established. More than 95% pure α -crystal, which was prepared from a solution of less than 5% monosodium glutamate, was effective as seeds in the crystallization process with the standard neutralization curve. Separation of the inhibitory material for β-transition of α-crystals was pursued using two kinds of testing methods in fractions of beet molasses broth treated with ion exchange resins. The neutral part of the beet molasses broth contained an active agent which was identified as saponin.