CHANGES OF SORGHUM GRAIN IN BOTH NUTRITIVE VALUE AND MORPHOLOGY DUE TO EITHER HYDROTHERMAL PROCESSING OR GERMINATION TREATMENT (PELLETING, EXTRUSION, FLUORESCENCE MICROSCOPY).

摘要

Sorghum grain (Sorghum bicolor (L.) Moench), a low tannin variety, was employed for either hydrothermal processing including pelleting and extrusion or germination treatment.;Neither process resulted in a change in the protein content, however, in vitro N digestibility was decreased by the extrusion. No change was observed by the pelleting.;Changes in amino acids composition were not significant. The content of both total and available lysine was not altered by both processing. Both NDF and ADF content was not changed during the pelleting and extrusion.;Swelling and deformation of starch granules, ruptured cell walls and stretched proteins were observed with SEM in the extruded sorghum grain and, to lesser magnitude, in the pelleted grain.;Part I. Sorghum starch was gelatinized by both pelleting and extrusion, with greater magnitude, by extrusion. However, there was no change in total starch content due to either pelleting or extrusion. In vitro DM digestibility was improved by both methods of processing.;Part 2. During germination, starch content of sorghum grain was gradually decreased as germination progressed. In vitro DM digestibility was eventually decreased with the progress of germination.;There were no changes in protein content and in vitro protein digestibility. Levels of amino acids except glutamic acid, proline and leucine were gradually increased during germination. A remarkable increase of aspartic acid content was noticed. Both total and available lysine contents were increased during germination.;Both NDF and ADF contents of sorghum grain were increased as germination advanced.;Part 3. Both SEM and FM studies revealed the modification of starch granules and proteins in the endosperm of sorghum grain during germination. Starch granules were modified by pitting. The modification is believed to commence from the crease edge of endosperm adjacent to the scutellum. The endosperm cell walls appeared to persist during germination.;Cell contents of both aleurone layer and embryo were degraded through both pitting and exterior erosion. However, their cell walls remain visually intact. Elongation of epithelial cell was evident during the early stage of germination.