The (1-3, 1-4)-β-Glucanases in Malting Barley: Enzyme Survival and Genetic and Environmental Effects

Abstract

Eighteen barley genotypes used in Brazilian malting barley breeding programs were characterized in relation to (1-3, 1-4)-␤-glucanase activity in green and kilned malt. They were tested to determine the loss of enzyme activity during kilning in the malting process and the environmental effects on enzyme activity were measured. The genotypes analyzed showed great variation regarding the enzyme activity in both kinds of malt, in a range from 531.94 to 934.31 U /kg in green malt, and from 187.02 to 518.40 U /kg in dry malt. The mean enzyme activity loss during kilning was close to 60%, very similar to the results obtained in other studies. The loss among genotypes varied from 8.04% to 71.54%. The enzyme activity varied significantly under the different environments tested, showing existence of environmental effects on the genotypes analyzed. Embrapa 127 was the genotype that exhibited the highest enzyme activity in finished malt although it had shown a low activity in green malt, reflecting a negligible loss of activity during kilning. The data indicate promising results to malting barley breeding due to the wide variability exhibited by genotypes as to enzyme activity and levels of isoenzyme with high thermostability.

The Impact of Kilning on Enzymatic Activity of Buckwheat Malt

“…The results in this study show a decrease in ␤-glucanase activity from 56.7 units kg -1 to 48.8 units kg -1 over the first 4 h of kilning. This confirms the findings of Georg-Kraemer et al 15 , where results indicate barley ␤-glucanase is highly susceptible to thermal inactivation depending on the grain variety. Over the final 43 h of kilning, buckwheat ␤-glucanase activity level decreased from 53 units kg -1 to 19.2 units kg -1 .…”

Genetic variability of irrigated barley in savanna environments based on malting quality

“…The correlation between viscosity and protein, friability and Hartong index, friability and β‐glucan varied for the Experimental Field of Embrapa Cerrados (CPAC) and Embrapa Produtos e Mercado (SPM) environments, showing that the interaction of genotype x environment causes unpredictable variation in quantitative characteristics, such as malt quality . Many genes are involved in malt quality and it is strongly influenced by the environment, especially high air temperature , which in the irrigated Cerrado coincides with the period of grain filling.…”

Desenvolvimento de populações duplo-haplóides de cevada cervejeira associadas à atividade das enzimas (1-3, 1-4)-β-glucanases

“…A seleção dos genótipos parentais para o desenvolvimento das populações duplo-haplóides (DHs) foi realizada com base na atividade das enzimas (1-3, 1-4)--glucanases de 18 variedades de cevada (GEORG-KRAEMER et al, 2004). Foram escolhidas duas cultivares com maior divergência quanto à atividade da enzima na etapa do malte verde (antes da secagem) e outras duas, igualmente divergentes, no malte final (malte seco), pois as cultivares que apresentaram maior divergência no malte verde não apresentaram maior divergência para o malte seco.…”