Wenwen Yu (1), Glen Fox (1); (1) University of Queensland, Brisbane, Australia

Malt and Grains

In this study, we looked at the kinetics of starch hydrolysis in raw barley flour to characterize the influence of barley protein on starch degradation rate. Raw barley flours with difference genetic backgrounds were prepared, while pure starches were also purified from raw flours. Our results showed that the digestion of barley starch following pepsin hydrolysis followed a single first-order rate constant while barley flour following no pepsin hydrolysis showed two sequential first-order rate constants. The confocal microscopy revealed that in barley the protein was attached loosely to the surface of starch granules, which, to some extent, has a limited effect on the degradation rate of starch granules. The protein matrix and protein composition account for the sequential kinetic steps in starch digestion of barley flour. These results can provide new knowledge about the effects of protein–starch interaction on the degradation of starch during malting and mashing in brewing.

Wenwen Yu graduated from South China University of Technology in 2014 with a master’s degree and is now a Ph.D. candidate at the University of Queensland. Wenwen Yu’s Ph.D. project is on interactions of barley endosperm proteins with starch and their effects on functional properties.