Pretreatment and Hydrolysis of Brewer's Spent Grains

Abstract

Brewer's spent grains (BSG), the voluminous residue after mashing, contains on dry weight basis about 40–50 % polysaccharides. For the recovery of soluble carbohydrates from BSG different physical, thermal and enzymatic treatments were used to solubilize the polysaccharides in BSG. Heating by microwave radiation to 160 °C in the presence of 0.1 M HCl released 35 % of the material in the form of reducing sugar, indicating that about 80 % of the polysaccharides were hydrolyzed. Nevertheless, 0.1 M acetic acid will even solubilize 30 % of the material as oligosaccharides on a prolonged incubation when pretreating the spent grains by extrusion cooking. A combination of the enzymes Ceremix Plus MG and CelluPract AL 70 achieved an almost 25 % release of saccharides after 4 hrs of incubation at 50 °C. A combination of extrusion cooking and enzymatic hydrolysis seems to be a very promising procedure.

Characterization of Lipids and Lignans in Brewer’s Spent Grain and Its Enzymatically Extracted Fraction

“…1,2,7,9,10 However, BSG contains bacterial and fungal spores that are not destroyed by the high temperature in mashing; 11 to avoid their extensive growth and hence spoilage of the material, the hydrolysis time has to be limited. Incubations of 4−5 h have been often reported, 1,10 but with current enzymatic methods, this time period can only release 50% of the total carbohydrates in a solubilized form.…”

Optimisation of ultrasonic-assisted protein extraction from brewer's spent grain

“…Due to the content of many beneficial components of BSG, the separation of BSG into its individual components for both food and nonfood applications is of interest. This research included the valorisation of BSG to recover valuable compounds such as α-tocopherol by supercritical fluid extraction (SFE) technology (Fernandez et al 2008), the recovery of ferulic acid from BSG by a sequential extraction with alkali of increasing strength (Mandalari et al 2005), solubilisation of BSG carbohydrates by microwave radiation at 160°C in the presence of 0.1M HCl (Macheiner et al 2003), the extraction of ferulic and p-coumaric acids by alkaline hydrolysis of BSG (Mussatto et al 2007a, b), the ecovery of lignin from BSG (Mussatto et al 2007a, b), and the production of oligosaccharides (Carvalheiro et al 2004).…”

Chromium(III) biosorption onto spent grains residual from brewing industry: equilibrium, kinetics and column studies

“…The difference in spent grains mass used in experimental assays results from materials different densities, with consequences in fluidization characteristics. The lower density of TSG is explained by intercrystalline swelling of cellulose by breaking down hydrogen bonding of adjacent glucose molecule in cellulose matrix caused by alkaline pre-treatment (Macheiner et al 2003).…”

“…Despite its potential as a valuable resource for industrial exploitation, spent grains, rich in cellulose and non-cellulosic polysaccharides, are frequently used as animal feed (Aliyu and Bala 2011;Li et al 2009a). Nevertheless, because of BSG chemical composition, particularly its considerable amount of dietary fibers, other applications have been explored: as an additive for dietary food, the production of fermentable sugars and soluble non-digestible oligomers that may act as prebiotics (Macheiner et al 2003), as immobilization support for microorganisms, namely brewing yeast and bacteria (Branyik et al 2004) and also as a biosorbent for heavy metals (Low et al 2000(Low et al , 2001Ferraz et al 2005;Li et al 2009a;Lu and Gibb 2008).…”