Effects of malting on phase transition behaviour of starch in barley cultivars with varying amylose content

The effect of malting an the phase transition behaviour of starch in barley cultivars with varying amylose content was studied using differential scan ning calorimetry (DSC). A slight elevation in the melting transition temper ature of amylopectin of malt starch and a pronounced decrease in gelatinisa tion enthalpy for both malt flour and starch were observed for all samples. Evidence was provided from the calorimetric data and the C-13 CP/MAS NMX s pectra that starch-lipid interactions in the form of complexes are enhanced as a result of malting. There was also a large reduction in the melting tr ansition temperature of the amylose-lipid complexes of malt flours, presuma bly due to partial degradation of amylose in malt, whereas the transition e nthalpies of the complexes increased for both malt flours and starches. The DSC transition characteristics of the three good malting barley cultivars grown in different locations and of their respective malts showed that envi ronmental conditions during starch synthesis have a great influence on star ch granule organization, and thereby affect the thermal stability of amylop ectin crystallites.