HYDROTHERMAL MODIFICATIONS OF GRANULAR STARCH, WITH RETENTION OF THE GRANULAR STRUCTURE - A REVIEW

Annealing and heat-moisture treatment are two hydrothermal treatments that modify the physicochemical properties of starch, without destroyi ng granular structure.; They involve incubation of starch granules in excess water/intermediate water content (annealing) or at low moisture levels (heat-moisture treatment) during a certain period of time, at a temperature above the glass transition temperature but below the gel atinization temperature. The impact of hydrothermal treatments on star ch physicochemical properties is extensively discussed. Such physicoch emical properties include granule morphology and crystallinity, double -helix content, amount and appearance of amylose-lipid complexes, gela tinization and pasting, swelling power and solubility; gel properties, and susceptibilities to acid and enzymic hydrolysis. Finally, the maj or differences between the effects of annealing and heat-moisture trea tment are pointed out and an overview is given of possible explanation s for the observed effects of hydrothermal treatments.