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ARS Home » Midwest Area » Madison, Wisconsin » Cereal Crops Research » Research » Publications at this Location » Publication #104608
Title: VARIATION AND GENETIC CONTROL OF FOAM-POSITIVE PROTEINS IN AUSTRALIAN BARLEY VARIETIES

Author
item EVANS, D - UNIVERSITY OF ADELAIDE
item RATCLIFFE, M - VICT. INST. DRYLAND AGRIC
item Jones, Berne
item BARR, A - UNIVERSITY OF ADELAIDE

Submitted to: Australian Barley Technical Symposium Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 8/12/1999
Publication Date: N/A
Citation: N/A

Interpretive Summary: Beer is made from barley that has been treated to turn it into malt. The ability of the malt to convert into good beer is partially determined by the proteins that are present in it. Three proteins, called 'Z4 protein', 'Z7 protein' and 'lipid transfer protein 1 (LTP1)' control the amount of foam that forms when beers are poured, and most people like their beers to have a good, strong foam. Antibodies that recognize these three proteins were used to measure their amounts in a series of Australian and international malting barley varieties. The amounts of the Z4 and Z7 proteins varied widely in the varieties examined and these variations were shown to be due to the activities of a small number of genes. Since the number of genes controlling the amounts of these proteins was small and some varieties were genetically able to produce relatively large amounts of the proteins, it should be easy for plant breeders to produce improved barleys that contain enhanced amounts of these compounds. Using these improved barley varieties will make it unnecessary for brewers to use artificial methods to improve the foam characteristics of their beers and should lead to the production of better, more wholesome beers.

Technical Abstract: The quantities of the 'Z protein' and LTP1 present in malts have been found to influence the foam quality of beers prepared from those malts. ELISA analyses developed to measure the levels of protein Z4, protein Z7 and LTP1 were used to survey the levels of these proteins in a range of Australian and international malting barley varieties. Substantial variation was observed in the levels of the proteins Z4 and Z7, and this variation was shown by genetic analysis to result from the expression of a small number of major gene/s. In addition, there was a positive association of the levels of these proteins with the overall barley protein content. Since the level of these proteins is under simple genetic control and positive alleles are available in adapted germplasm, it should be possible for barley breeders to readily increase their levels in future barley cultivars. It is expected that increasing the levels of the foam-positive proteins in malt will reduce the need for brewers to use artificial methods to supplement the foam levels in beers. This should improve the desirability, shelf-life, cost and wholesomeness of the beers that are produced.