Valorization of Bioactive Compounds Extracted from Brewer's Spent Grain (BSG) for Sustainable Food Waste Recycling

In parallel with the worldwide issues of malnutrition and food waste, society at large focuses on the advantages of 'recycling' food waste. Brewer's spent grain (BSG), a primary byproduct of the brewing industry, is produced in large quantities in many regions of the world, leading to environmental issues. The present study aimed at valorizing BSG through bioactive compound extraction using more traditional approaches, including Soxhlet extraction, recrystallization, and salting-out adsorption for proteins and lactic purification. The extraction rate of total dietary fiber (TDF) was 93.3%. FTIR analysis showed specific structural vibrations of fiber with C-O and C-O-C attachments in hemicellulose, C-H bends in lignin, and various bending patterns in tannins and fatty acid esters. Hemicellulose (8245.2 mg/L), lignin (10,432.4 mg/L), and cellulose (13,245.4 mg/L) were extracted with rates of 54.9%, 69.5%, and 88.3%, respectively. These bioactive compounds extracted from BSG could be utilized in food and nutraceutical products based on their purity. The analysis of extracted bioactive components confirmed the presence of arachidic acid (C20:0), oleic acid (C18:1), linoleic acid (C18:2), myristic acid (C14:0), pentacyclic acid (C30:0), palmitic acid (C16:0), margaric acid (C17:0), gallic acid, catechol, ellagic acid, acetyl sialic acid, benzoic acid, and vanillin. These findings highlight the valorization potential of BSG, a previously regarded waste material, as a source of active biocomponents. This is consistent with the principles of the circular economy by reducing waste in the environment and supporting tangible sustainability in food systems. The efforts made in the current study in utilizing BSG are part of the fast-growing area of food waste recycling and provide a way to avoid waste and create added value.