The most important malting enzyme, free beta-amylase, comes from a layer of tissue in the barley grain called the aleurone, a health-promoting tissue full of minerals, antioxidants and dietary fibre. The researchers at the University of Adelaide showed that the more aleurone present in the barley grain, the more enzyme activity the grain produced.
The findings could lead to the development of new barley varieties that deliver more fermentable sugar and breakdown complex sugars faster.
Project leader Associate Professor Matthew Tucker from the University Adelaide’s School of Agriculture, Food and Wine said the 36 varieties looked at in the study were all parents of breeding material and the results were quite surprising.
However, he said enzyme levels were just one of several factors along with protein levels and starch content that contributed to malt quality.
“People have known that aleurone has been there for years and the role of it has been known for years but to be able to look inside the grain using powerful microscopes and techniques you can actually extract a lot more information than was possible,” Associate Professor Tucker said.
“We’ve got the fundamental science and now we’ve got the opportunity to look at the applied context.
“We’ve certainly had some interest from some breeding companies and also from some brewing companies.”
The research has been published in the Nature publication Scientific Reports.
A follow-up study looking at European barley cultivars sourced from a barley breeding institute in Scotland is underway to determine if the same science can be applied to whisky.
Associate Professor Tucker said the university might also do a similar study with wheat to maximize the health benefits derived from nutrients in the aleurone layer.
He said a variety with a high aleurone count could have 15-20 per cent more enzymes than a barley variety with low aleurone levels.
“What we’re reporting in this study is the physiology – how it happens during growth and development – but underneath all that are some genes that are controlling the formation of the aleurone layers so we’ve invested quite a lot of time trying to find out what they are and once we find them we can pass that information on to breeders,” Associate Professor Tucker, pictured below, said.
“We think our findings show that it might be possible for breeders and geneticists to make use of this natural variation to select for barley varieties with different amounts of aleurone and hence different malting characteristics.
“Particularly for South Australia, barley is a really important crop and having companies like Coopers investing and all the craft breweries springing up around the place I think it’s a growing area and there is still potential for it to grow more in Australia.”
Barley is the second most important cereal crop for South Australia and contributes over $2.5 billion to the national economy. Much of its value comes from its use in beer and beverage production.
Associate Professor Tucker said it was not yet known if malts using barley with higher aluerone levels would impact beer flavour.
“We don’t really know but certainly we do know that in the cultivars that have more aluerone they definitely have different levels of antioxidants, minerals and dietary fibre and they may contribute to the flavours you get in the end,” he said.
“That’s been done a lot in wine where they look at the grapes and how their properties might contribute to wine flavour but not so much research has been done with barley in the context of beer.”Jump to next article