Synopsis
The study of anisotropy light scattering from tapioca and potato starches has continued with the recording of more detailed experimental single-granule H , scattering patterns and, for the first time, singlegranule V , patterns. Quantitative analysis of the relative intensity distribution in experimental H , patterns reveals the sensitivity of the higher order scattering maxima to the granule morphology, permitting an analysis of the latter in terms of a layered structure. For tapioca starch, this analysis indicates that if layering is present a t all, the layer thickness is comparable to the wavelength of the incident radiation, and most likely is considerably less than 0.5 p in thickness. On the other hand, the potato starch morphology is characterized by a relatively coarse layering with few layers and considerable difference in the anisotropy between successive layers. The models for the two starches in best agreement with experimental data are as follows: almost perfectly spherulitic anisotropic structure with very thin shell-like layers-if any-for tapioca, and alternating layers of varying anisotropy several microns in thickness and probably simultaneously present with an isotropic center, for potato starch. The V , pattern for tapioca starch is in agreement with this model, although its information content is lower owing to the experimental difficulty of recording higher order maxima. Suggestions for further morphological study of starches are presented.