Preparation and Characterization of High Purity Anhydrous β-Lactose from α-Lactose Monohydrate at Mild Temperature

Abstract EN

Lactose is a disaccharide of importance in humans dietary, food products, and the pharmaceutical industry.

From the existing isomeric forms, β-lactose is rarely found in nature.

Thus, in this work, a simple methodology to obtain anhydrous β-lactose (βL) from α-lactose monohydrate (αL·H2O) is presented.

The αL·H2O powder was dispersed into a basic alcoholic solution (72 hours), at controlled conditions of temperature (27, 29, 31, and 32°C), without stirring.

The slurry was dried at room temperature and characterized.

Fourier transform infrared spectroscopy showed the formation of βL for the samples prepared at 29 and 32°C.

Raman spectroscopy confirmed this result and suggested the occurrence of crystalline βL.

Rietveld refinement of the X-ray diffraction patterns was employed to identify and quantify the composition of the isomers.

The samples prepared at 29 and 31°C showed the formation of pure βL, while those at 27 and 32°C showed the presence of αL·H2O and a mixture of the two isomers, respectively.

The morphology of the powders was studied by scanning electron microscopy, observing the formation of irregular shape αL·H2O particles and axe-like βL particles.

Clearly, with this methodology, it was possible to obtain pure, crystalline, and anhydrous βL at mild temperature.