Study On Evolution Of Barley Anti-yeast Protein During Malting

Barley is the main raw material for brewing, it determine the fermentation process andbeer quality. Previous studies showed barley anti-yeast proteins could inhibit yeast growth andtolerate the temperature of boiling wort in fermentation process, and because of this, theseproteins have adverse effect upon fermentation of beer.In this study, the Sebastian Barley was used as test samples, the purpose of this paperwas to study the cause of anti-protein forming, try to give a guideline for further research.Some kinds of mildew were inoculated to study the effect of mildew on anti-yeastprotein content. The results show that, the anti-protein content of inoculated barley treatmentgroup is higher than control group at the end of malting. The anti-protein content is572μg/gin Fusarium poae-inoculated group, which is the highest, and it raised14.9%when the proteincontent in control group is498μg/g. Protease activity was detected, it higher in normal barleythan the barley inoculated by mildew at the end of malting.NaCl, KCl and CaCl2were added during barley steeping. The results showed that thecontent of anti-yeast protein was the highest in1.0%NaCl and KCl treatment groups in thegroups treated with NaCl and KCl, the content of the protein was the lowest in0.5%NaClgroup, the same to0.5%KCl. In treatment groups treated with CaCl2, the content was thehighest in control group, it reach to515μg/g, and was the lowest in0.5%group. So the Ca2+could reduce anti-yeast protein content, all the content of anti-yeast protein in three treatmentgroups were lower than control group. NaCl, KCl and CaCl2had inhibition on barley proteaseactivity, the higher of the content, the lower of the protease activity.GA3、ABA and6-BA were added during barley steeping. At the end of malting, thecontent of anti-yeast protein is the highest in0.05mg/L GA3group of groups treated withGA3, it reached to566.6μg/g, and the content of anti-yeast protein in0.5mg/L group was thelowest; the content of anti-yeast protein was the highest in20mg/L group of groups treatedwith ABA, it was514.9μg/g, in40mg/L group is the lowest; the content of it was the highestin20mg/L6-BA group of groups treated with6-BA, it was484.4μg/g, in10mg/L group was the lowest.