EFFECT OF ANNEALING ON THE HYDROLYSIS OF SAGO STARCH GRANULES

Sage starch annealed at varying temperatures, time intervals and pH wa s used to study granule hydrolysis by a glucoamylase (AMG) and a-amyla se (Termamyl) mixture. Differential scanning calorimetry (DSC) indicat ed that there was a relationship between the extent of annealing and s tarch granule hydrolysis. Enthalpy of gelatinisation of annealed starc h granules remained unchanged, suggesting that no gelatinisation had o ccurred. The degree of hydrolysis increased and the granule degradatio n pattern altered-from surface erosion to preferential digging of the internal regions of the granule. Sections of the hydrolysed granule re sidues revealed that enzymes attacked from one point on sufficiently a nnealed granules, and that after extensive hydrolysis, only an empty s hell remained. (C) 1997 Elsevier Science Ltd.