Virginia Tech scientists extract protein and fiber from brewer’s spent grains

April 21, 2021 |

In Virginia, Virginia Tech scientists report a new way to extract the protein and fiber from brewer’s spent grain and use it to create new types of protein sources, biofuels and more. 

Craft brewing has become more popular than ever in the U.S. This increased demand has led to an increase in production, generating a major uptick in waste material from breweries, 85% of which is spent grain. This byproduct comprises up to 30% protein and up to 70% fiber, and while cows and other animals may be able to digest spent grain, it is difficult for humans to digest it because of its high fiber content.

In order to transform this waste into something more functional, researchers developed a novel wet milling fractionation process to separate the protein from the fiber. Compared to other techniques, the new process is more efficient because the researchers do not have to dry the grain first. They tested three commercially available enzymes — alcalase, neutrase and pepsin — in this process and found that alcalase treatment provided the best separation without losing large amounts of either component. After a sieving step, the result was a protein concentrate and a fiber-rich product.

Up to 83% of the protein in the spent grain was recaptured in the protein concentrate. Initially the researchers proposed using the extracted protein as a cheaper, more sustainable replacement for fishmeal to feed farmed shrimp. But more recently, Huang and He have started to explore using the protein as an ingredient in food products, catering to the consumer demand for alternate protein sources.

Next, the team plans to work on scaling up the process of separating the protein and fiber components in order to keep up with the volume of spent grain generated at breweries. They are also working with colleagues to determine the economic feasibility of the separation process, as the enzymes currently used to separate the protein and fiber components are expensive. 

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Category: Research

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