Abstract:

The scanning electron microscopy(SEM), Fourier-transform infrared spectroscopy(FTIR)and X-ray diffraction(XRD)were applied to characterize the morphology, chemical and crystalline structures of several Castanopsis carlesi modified starches. The formation procedure of micro-porous starch is that the hollows in the surface of starch granule can be hydrolyzed from the outside to the inside, and be further punctured through the granule center by the mixture solution of α-amylase and glucoamylase, finally the net-cavity structure of starch granule which is distributed by plenty of about 1 μm holes can be made. The carbonyl groups and glycosidic bonds in starch carbon chains can be enzymatic-hydrolyzed, while phosphide ester linkage can be formed by crosslinking reaction between hydroxyl groups in starch carbon chains and POCl₃. Whichever native, microporous, crosslinked or crosslinked microporous starch granule is a multi-crystal system which made from crystal and non-crystal,and belong to C-type crystalline. The crystalline degree and crystal size of crosslinked, native, crosslinked microporous and microporous starch increase in sequence, while the change of crystal interval is just adverse.

Key words: Castanopsis carlesi, modified starch, structural properties