Abstract

Brewer's spent grain (BSG) is a by-product of the brewing industry that retains several bioactive compounds of interest, including soluble dietary fibers, proteins, peptides, and polyphenols. Despite its composition, BSG is often discarded or used as low-value animal feed. To enhance its value and contribute to a more sustainable brewing supply chain, recent studies have explored the functional applications of BSG and its derived fractions and extracts. This review focuses on the prebiotic and antimicrobial activities of fiber-rich BSG fractions with potential applications in the food industry. A systematic literature search was conducted using the Web of Science database, yielding 166 articles. Following the application of defined inclusion and exclusion criteria, 28 studies were selected for detailed analysis. Key findings reveal that processed and purified BSG fiber extracts, particularly those containing arabinoxylans, arabinoxylo-oligosaccharides, and xylo-oligosaccharides, demonstrate promising prebiotic properties that may support gut health. In addition, in vitro studies show that BSG extracts can inhibit the growth of food spoilage organisms and pathogenic microbes. This review highlights the need for continued research into optimized extraction and purification techniques to fully realize the potential of BSG fibers and antimicrobial components in food applications.