Hydration and physicochemical properties of small-particle cassava starch

Acid hydrolysis followed by ball milling was applied to cassava starch in order to fracture the granules. Lintnerisation led to degradation first in the amorphous domains and increased the crystallinity. The resulting increase in internal defects and brittleness made the granules more susceptible to breakage upon milling. Ball milling, although leading to some degree of crystallinity loss, could effectively reduce the size of acid-hydrolysed starch while the total double helix remained relatively unchanged. The resulting small-particle starch was structurally more heterogeneous (wider T-m range). Swelling of small-particle starch was accompanied by solubilisation of water-soluble fragments at a temperature greater than 60degreesC. The properties of individual granules are strongly influenced by the hydration and physicochemical properties of their amorphous and crystalline domains. (C) 2002 Society of Chemical Industry.