Changes in β-Amylase Enzymes of Barley During Malting. D. E. LaBerge and B. A. Marchylo, Grain Research Laboratory, Canadian Grain Commission, Winnipeg, Manitoba, Canada, R3C 3G8. J. Am. Soc. Brew. Chem. 45:0140, 1987.

Three barley cultivars, Bonanza, Diamond, and Klages, were used to study changes in β-amylase enzymes during malting. Freeze-dried samples taken after 24 and 48 hr of steeping and after one, two, three, four, and five days of germination were analyzed by chromatofocusing and polyacrylamide gel isoelectric focusing. The effect of kilning on β-amylase components of malt also was studied. Chromatofocusing analysis indicated that during steeping and early stages of germination, barley β-amylases disappear or decrease to low levels concomitant with the production of at least two new β-amylase components that have higher apparent pI values. Diamond produces primarily β-amylase "A" (apparent pI 6.89), Klages primarily β-amylase "B" (apparent pI 6.68), whereas both enzymes are produced in malts prepared from Bonanza barley. Polyacrylamide gel isoelectric focusing analysis provided evidence that confirmed the changes observed by chromatofocusing. These enzymes also are produced by extracting ground barley directly with papain.

Keywords: Barley, β-Amylase, Chromatofocusing, Polyacrylamide gel isoelectric focusing (PAGIEF)