Glucose and fructose adsorption on sucrose crystals. Their role as habit-modifiers

Experimental evidences show that α-D-glucose and β-D-fructose work as habit-modifiers of sucrose crystals grown from aqueous solutions at high concentration only. Their ability to affect the sucrose habit is examined from structural point of view, through stereochemical analysis of both additive molecules and surface sites on some significant polar and non-polar forms of sucrose crystal. We referred to the classical TLK (terraces, ledges, kinks) model and restricted the adsorption interactions to the H-bondings only. Notwithstanding the simple qualitative model we adopted, our method of analysis appears satisfactory to interpret analogies and differences in selectivity between glucose and fructose. However, it is not able to explain why the additive concentrations, needed to induce macroscopic effects, are so high. To clear this aspect, we assumed a behaviour as "disruption tailor-made additives" for both monosaccharides. Finally, sucrose crystals grown in the presence of equimolecular...