Dehydration in Model Systems: Cellulose and Calcium Pectinate

SUMMARY Cellulose, containing some resistant hemicelluloses, was prepared from the phloem of carrot tap‐roots, and a similar extraction procedure was used for cotton fibers. A calcium pectinate gel was also made, and all three materials were dehydrated at two different rates and stored for 6 months. Proportionate crystallinity was determined on the basis of differences in moisture content, water vapor sorption, X‐ray diffraction intensity, iodine adsorption, enzymatic digestibility, and density. In all cases, dehydration resulted in an increase in crystalline content of the samples, rapid dehydration seeming to produce somewhat greater crystallinity than slow dehydration. (Some spurious results with calcium pectinate are discussed.) Uniformly, all materials became more crystalline on standing, and the products of the two different drying rates attained virtually the same crystallinity values, per sample type, after 6 months. Calcium pectinate had the highest amorphous content, carrot cellulose the next highest, and cotton cellulose the lowest.