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ARS Home » Northeast Area » Wyndmoor, Pennsylvania » Eastern Regional Research Center » Sustainable Biofuels and Co-products Research » Research » Publications at this Location » Publication #418310

Research Project: Chemical Conversion of Biomass into High Value Products

Location: Sustainable Biofuels and Co-products Research

Title: Isolation and characterization of the physiochemical properties of Brewer’s spent grain

Author
item MAINALI, KALIDAS - Oak Ridge Institute For Science And Education (ORISE)
item Yadav, Madhav
item Sharma, Brajendra - Bk
item Sarker, Majher
item Ngo, Helen
item Hotchkiss, Arland
item Simon, Stefanie

Submitted to: Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/26/2024
Publication Date: 12/28/2024
Citation: Mainali, K., Yadav, M.P., Sharma, B.K., Sarker, M.I., Lew, H.N., Hotchkiss, A.T., Simon, S. 2024. Isolation and characterization of the physiochemical properties of Brewer’s spent grain. Agriculture. 15:47. https://doi.org/10.3390/agriculture15010047.
DOI: https://doi.org/10.3390/agriculture15010047

Interpretive Summary: Brewer’s spent grain (BSG) is an abundant low-value side stream of the brewing industry which can be utilized to make functional products for food and industrial purposes. It is rich in various plant fibers that may have numerous applications. Previous studies in our lab have reported a method to produce functional materials from other fibrous agricultural processing by-products. In this study, we have isolated and characterized four functional fractions of BSG: hemicellulose A, hemicellulose B, cellulosic-rich fraction (CRF), and oligosaccharides. Standard proximate analysis done in our lab has shown that hemicellulose A fraction has the highest protein content (66 wt. %). Based on our previous study, hemicellulose B, CRF and oligosaccharides can potentially be used as dietary fibers in many food products. Hemicellulose B has the potential to be used in beverages as a flavor stabilizing agent. Isolating and characterizing these functional components present in the brewing industry waste will offer a unique opportunity to add value to the brewers by using their waste stream and make high value food and non-food ingredients. It will also benefit the US barley growers, whose barley grains are utilized in the brewing process.

Technical Abstract: Large quantities of the brewer’s spent grains are not fully utilized even as cattle feed. These feedstocks can be used to produce highly functional biomaterials, carbonaceous materials and additives. In this investigation, four major fractions were isolated and characterized: Hemicellulose A, Hemicellulose B, cellulosic-rich fraction (CRF), and oligosaccharides. Overall, 21.4 % Hemi. A, 18.5 % Hemi. B, 17.4 % CRF, and 5.5 % pure oligosaccharides were obtained from the hexane extracted brewery’s spent grains. The detailed physio-chemical analysis of each fraction shows that these fractions can be used to produce useful products such as emulsifiers, carbonaceous materials, modified cellulosic fibers, additives as well as N-doped chars. Component analysis revealed that, Hemi. A contains high fixed carbon (20 wt.%), followed by hexane extracted material (17.1 wt.%), CRF (14.6 wt.%) and Hemi. B (14.5%). Standard proximate analysis showed that Hemi. A has the highest protein (66 wt.%), which can be utilized as a renewable solid-state N-precursor as dopants during the thermochemical conversion process. The sugar composition revealed that BSG has a typical arabinoxylan structure with high percent of arabinose and xylose. It also contains a high percent of glucose, which can be coming from the residual ß-glucan present in the BSG. FTIR analysis revealed changes in the structure of each fraction. Hence, BSG and extracted fractions exhibit significant potential for waste valorization, contributing significantly to the full utilization of products from the brewing industry.