Probing Heat-stable Protein From Barley To Malt

Barley is the most important raw material for beer production, proteins are among thebarley components that are essential for the quality of malt and beer. In fact, the aim of themalting process is the production and activation of enzymes. Theses molecules also contributeto the hydrolysis of starch, protein and hemicellulose. In this regard, heat-stable proteins ofbarley for their heat resistance play a major role in flavor, taste, foam quality and beer colloidstability. The heat-stable proteins from barley and germinated barley were investigated in thispaper and the result showed that heat-stable protein profile was similar from different barleyvarieties and different protein content barley, so that could be an important index to the barleyvariety identification. However, the heat-stable protein content of barley was change with thetotal protein content, the heat-stable hordein content was the highest and increased with thetotal protein content increasing. Some heat-stable protein profiles disappeared duringgermination, and heat-stable hordein proteins were exposed to a proteolytic process, whichreduced its content. In contrast, heat-stable water-soluble proteins increased by the end of thegermination process.Barley heat-stable proteins are involved in the formation, stability, and texture of headfoams. Heat-stable water-soluble proteins from barley and malt were investigated forcomparative analysis in this paper. The result indicated that different barley variety samplespresented similar heat-stable water-soluble protein profile, and protein content increasedduring the germination process. As expected, from barley to malt and beer, most of theheat-stable water-soluble proteins were similar, Therefore, the beer protein profile could beevaluated according to the heat-stable water-soluble protein profile of barley or malt, whichinvolved in the development of high-quality value malt and beer by improving the maltingand brewing technology. However, some protein Z could be eliminated by silica gelabsorption, which imply that it was also haze-active protein.Heat-stable water-soluble proteins of barley was changed due to protease and theiractivities were effected under salt stress. Heat-stable water-soluble proteins from germinated barley under salt stress were investigated and the protease activity was determined to monitorthe secreted protease change during germination. The result showed that protease activity wasinhabited under sodium salt stress, and the heat-stable water-soluble protein content was notincreased obviously.In contrast, the protease activity was not restrained and the heat-stablewater-soluble protein content increased markedly under low concentration calcium salt stress.However, their activities was weakened and the heat-stable water-soluble protein content wasnot increase significantly under high concentration calcium salt stress.In sum, Sodium dodecylsulfate-polyacrylamide gel electrophoresis (SDS-PAGE) andBradford methods were used for comparative studying the heat-stable proteins from barleyand germinated barley in this paper, which involved in the development of high-quality valuemalt and beer by improving the malting and brewing technology.