New research unveils the journey of sorghum in beer brewing, its potential as a gluten-free alternative, and how proteomics are being used to help reshape the future of industrial beer production.
Brewing beer is an ancient way of putting chemistry to use, with evidence of controlled fermentation as many as 13,000 years ago. Beer is one of the most popular beverages on a global scale, with almost 280 billion liters sold in 2022. It is traditionally brewed using malted barley, but alternative recipes offering different flavor profiles and characteristics have gained popularity—including gluten-free varieties.
Many people are gluten intolerant, have celiac disease, or choose to avoid gluten for other health reasons. Gluten is a type of prolamin, a group of proteins used for storage in grass seeds. These prolamins contain high proportions of proline and glutamine, resisting proteolysis during digestion. In some people, this makes them highly immunogenic, and they can cause a destructive cascade of reactions that eventually damage the small intestine, reduce nutrient absorption, and negatively impact overall health. A promising alternative is sorghum, a naturally gluten-free grass and a staple ingredient throughout much Africa—including for traditional fermented drinks. But the malting processes are very different to traditional barley grains, and to commercialize sorghum beers might require a different approach.
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In a new study published in the Journal of Proteome Research, researchers set out to use proteomic and metabolomic approaches to gain insights into the sorghum brewing process, with the intention of developing efficient beer production techniques for this alternative grain. The team brewed both barley and sorghum, taking them through malting, mashing, and fermentation—and varying temperatures and time at different steps.
A key finding was that malting sorghum does indeed synthesize the amylases and proteases necessary for brewing, but mashing with sorghum compared to barley malt requires higher temperatures for efficient protein solubilization. This could be critical, since although sorghum proteins and starch have high solubilization temperatures, its enzymes are comparatively heat sensitive.
Although we’ve been doing it for thousands of years, modern beer production is a complex industrial process, and some of the biochemical details have not always been clear. This isn’t the first time mass spectrometry proteomics have been employed to analyze the proteins present across time during nanoscale beer production. A previous paper, also published in the Journal of Proteome Research, revealed that many proteins are modified by protease digestion, glycation, or oxidation during the various processing steps. Work in this field allows us to improve beer production and quality control, as well as better understand the mechanisms controlling the diverse sensory properties of beer.
The authors conclude that sorghum could be a viable grain for industrial fermented drinks production, but incorporating it on a commercial scale will need careful process optimization for efficient production and high-quality beer.
