Solid-State Matrix Effects on Near-Infrared Spectra: Interactions of Glucose and Sucrose with Amylose,Amylopectin,Cellulose,and Starch—Implications for Near-Infrared Calibrations

Abstract

The objective of this work was to explore the question of how the interactions between carbohydrate monomers and polymers affect near-infrared spectra and to evaluate the implications of such effects with respect to the development of near-infrared calibrations. The effects of the presence of amylopectin, amylose, cellulose, and starch during the drying of glucose and sucrose on the resulting spectra were investigated. Sugars in various molar ratios with polymers were dried in a rotating mixer and then reground, and spectra from 10,000 to 4000 cm⁻¹ were taken. In addition, spectra of identical mixtures prepared by mixing previously ground sugars and polymers were taken for comparison. Results on samples prepared either by simple mixing of sugars and carbohydrate polymers or by grinding mixtures produced by drying sugars in the presence of polymers indicated that interactions occur between the substances in question. Although simple mixtures of sugars with cellulose, amylose, amylopectin, or starch showed some spectral changes in the spectra of the sugars, in general, the spectra obtained by spectral subtraction were considerably more similar to those of the pure sugars than were those obtained for materials dried together.