Book chapter
The properties and genetics of barley malt starch degrading enzymes
Genetics and Improvement of Barley Malt Quality, pp.143-189
Springer Berlin Heidelberg
2009
Abstract
The properties and quality of barley malt starch degrading enzymes are of primary importance to the efficiency and profitability of brewing (beer and whiskey), and the bio-fuel (bio-ethanol) industries. The barley starch degrading enzymes hydrolyse starch into fermentable sugars that yeast converts into alcohol. This process is key for the alcohol producing industries as the starch substrate makes up approximately 60% of grain weight (Holtekjolen et al., 2006). Malted barley is the main source of the diastase or diastatic power (DP) enzymes that hydrolyse starch. The DP enzymes comprise the combined activity of α-amylase, β-amylase, α-glucosidase and limit dextrinase whose concerted action hydrolyse the α-(1,4) and a-(1,6) glucosyl linkages in starch (Fig. 6.1) into fermentable sugars (i.e., glucose, maltose, etc.), dextrins and limit dextrins. The actions of the DP enzymes are summarised as follows:
(1) α-amylase cleaves α-(1,4)-linkages internally (endo-acting) to primarily produce oligosaccharides, limit dextrins and some fermentable sugars;
(2) β-amylase cleaves α-(1,4)-linkages from the non-reducing ends (exo-acting) to produce maltose;
(3) Limit dextrinase hydrolyses internal a-(1,6)-linkages (endo), to remove branch-points in amylopectin or α-limit dextrins;
(4) α-Glucosidase primarily cleaves α-(1,4)-linkages from the non-reducing ends to produce glucose
Details
- Title
- The properties and genetics of barley malt starch degrading enzymes
- Authors/Creators
- D.E. Evans (Author/Creator) - University of TasmaniaC. Li (Author/Creator) - Department of Agriculture and Food Western AustraliaJ.K. Eglinton (Author/Creator) - The University of Adelaide
- Contributors
- G. Zhang (Editor)C. Li (Editor) - Department of Agriculture and Food Western Australia
- Publication Details
- Genetics and Improvement of Barley Malt Quality, pp.143-189
- Publisher
- Springer Berlin Heidelberg
- Identifiers
- 991005544498907891
- Copyright
- 2009 Springer-Verlag Berlin Heidelberg
- Murdoch Affiliation
- Murdoch University; Centre for Crop and Food Innovation
- Language
- English
- Resource Type
- Book chapter
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