Digestion of sorghum grain endosperm in the rat and pig observed by scanning electron microscopy.

Abstract

Scanning electron microscopy was used to observe starch granule and endosperm cell wall digestion in the digestive tract of rats and pigs. Minute starch granule damage occurred in samples recovered from the rat stomach. Hydrolysis of exposed starch granules was prominent in split kernels recovered from the rat and pig jejunum. Several layers of endosperm cell walls were broken as the kernels passed through the small intestine, although cell walls diminished amylolysis of underlying starch granules. At any one time, amylolysis occurred in a single layer of cells below exposed endosperm. The enzymes apparently diffused through the cell wall. The nature of starch granule erosion was identical in the small intestines of rats and pigs; erosion of the waxy and yellow endosperm of sorghum grain hybrids differed widely between the species. Amylolytic pattern in samples from the small intestine were analogous with those from the caecum, large intestine and faeces. Breaks in the cell walls of the endosperm increased slightly during digestion in the caecum and large intestine. Most of the pericarp escaped hydrolysis