Proteomic analysis of two malting barleys (Hordeum vulgare L.) and their impact on wort quality

Malted barley contributes directly to wort quality. Wort prepared with malt M1 had a higher free amino nitrogen content, whereas wort prepared with malt M2 had a higher diastatic power. The proteome analysis (pI 3-10) in 2D-PAGE gels showed significant differences, with M1 generating 246 ± 9.8 spots and M2 229 ± 9.8 spots. M1 had more hydrolytic enzymes, in particular an esterase with a size of 43.7 kDa and a pI of 9.4, whereas M2 had more proteins involved in stress tolerance and carbohydrate metabolism, particularly a β-glucosidase with a size of 58.7 kDa and a pI of 7.7, which coincided with its higher diastatic power. The biological activity of M1 showed a band at ca. 150 kDa with high proteolytic activity and another band at 27 kDa with amylase activity. This study is the first report of amylase activity of small molecular size in malts.