Effects of wheat protein compositions on malt quality

Wheat protein is one of the quality-determining factors of wheat malt. In the present study, wheat protein compositions and malt quality were determined to examine their correlation. During malting, gliadin and glutenin decreased, albumin and globulin increased and the wheat insoluble protein, especially glutelin, determined the dissolved degree of protein. As the wheat insoluble/soluble protein ratio increased, free a-amino nitrogen (FAN) of malt appeared to rise to a peak and then decreased significantly. FAN was the highest when the ratio was 2.23. With the increase in the insoluble/soluble protein ratio, extract, Kolbach index and saccharification time of the malt underwent a significant linear decrease (r=-0.934, 0.973 and 0.950, respectively). The research results indicated that the wheat protein content has to be in the range of 12.72-13.88% to obtain satisfactory wheat malt quality, and the insoluble/soluble protein ratio should be in the range of 1.44-2.23.