Fructo-oligosaccharides and sucrose crystal growth morphology - I. Experimental growth habits

Because in both cane and beet molasses fructo-oligosaccharides are normally present, the effect of such compounds on sucrose crystal growth morphology has been tested. Sucrose crystals nucleated in the presence of the above m entioned compounds showed an unusual triangular shape as a consequence of t he abnormal development of the sizes of o-{1 (1) over bar}, q-{0 (1) over b ar 1}, w-{1<(11)over bar>} forms and the considerable decrease of that of p -{1 (1) over bar 0} form, up to the disappearance of the [001] edge between its faces. If the crystals grew on, even the o'-{111}, q'-{011}, w'-{11 (1 ) over bar} forms appeared and steadily increased in size on the right pole , so decreasing the size of p'-{100} form. Consequently, even the right [00 1] edge disappeared, so that the final growth habit of the crystals exhibit ed an unusual "rhombic" shape. Growth morphologies of sucrose twins, grown under the same experimental conditions, were in agreement with those observ ed for single crystals. Finally, the ratios between the face kinetics, whic h have to be considered as inducing the observed habits, are qualitatively discussed.