FOOD. Science. Technology. Quality

Food. SCIENCE. Technology. Quality

Food. Science. TECHNOLOGY. Quality

Food. Science. Technology. QUALITY




Studies on starch gelatinization and retrogradation with dynamic rheometry - the influence of starch granular structure and composition


The study on the starch gelatinization and retrogradation with dynamic rheometry are reviewed. Three typical varieties of rice starches, including indica (KSS7), japonica (TNu67) and waxy rice (TCW70) are used during the discussion. The amylose contents are 24-26 % for KSS7. 15-16 % for TNu67, and 0.8-1.0 % for TCW70. The heating and cooling behaviours of the individual starch, the combination of two starches, and the addition of amylose to the starch systems are discussed. The correlation between swelling power, amount of water soluble, blue value, and λmax, as well as gelatinization temperature, and the dynamic rheogram are applied for the elucidatięm of relationships between the starch molecular and granular structures, and the gelatinization and the retrogradation mechanisms. Generally, the G’ increases in gelatinization process of starch is mainly governed by the granular characteristics, which include the rigidity of swollen granule and the interaction between these close-packed granules. However, the G’ in starch retrogradation is influenced by the interaction between leached-out or external added amylose itself and swollen granule, in addition to the property of swollen granule. As for the mixed starch system, the combination of waxy and non-waxy starches will decrease G’ drastically. Whereas the addition of amylose molecule will decrease the G’ for the gelatinization process, but will increase G’ during cooling and aging profoundly. Hence, it is suggested that the starch granular properties and characteristics are the major factor for the starch rheological behavior, followed by the leached-out amylose during gelatinization process, especially in the high concentration system.