Malting characteristics of sorghum cultivars

Abstract

Malting properties were investigated for 16 sorghums using a germinator method and for six sorghums using a jar method. Density of caryopses decreased for all sorghums after malting. Dry matter losses ranged from 8 to 19%. alpha-Amylase activity determined by colorimetric assay ranged from 25 to 183 U/g, with two cultivars having activity levels similar to that of a commercial barley malt. Reduction in pasting viscosity was significantly correlated with alpha-amylase activity. Sorghum diastatic power (SDU) was positively correlated to alpha-amylase activity in cultivars with SDU values greater than 30. beta-Amylase activity was low, ranging from 11 to 41 U/g. The jar malting method yielded malts with lower dry matter losses and low levels of alpha- amylase and beta-amylase activity, except for one cultivar. To obtain the highest levels of enzyme activity with the lowest dry matter losses, malting conditions need to be controlled and optimized.