Current extraction techniques towards bioactive compounds from brewer’s spent grain – A review

Abstract

Background: Brewer’s spent grain is one of the most abundant by-products of the brewing industry and is rich in various bioactive compounds (phenolic acids, insoluble dietary fiber and proteins). While at the present brewer’s spent grain is mainly used as animal feed its rich nutritional content makes it an interesting alternative for food applications. Scope and approach: As the range of applications of the bioactive compounds extracted from by-products has been growing in recent years, there is the need to obtain and characterize these bioactive compounds. Extraction methods (supercritical carbon dioxide, autohydrolysis, alkaline hydrolysis, solvent extraction, ultrasound assisted extraction, dilute acid hydrolysis, enzymatic hydrolysis, microwave assisted extraction) have been developed and are always being subjected to new approaches to allow better extraction yields of the bioactive compounds. Key findings and conclusions: This review aims to provide a better understanding of the current advantages and limitations of brewer’s spent grain extraction processes and to provide a background of brewer’s spent grain composition and applications.

Highlights

• The re-use of agro-industrial by-products can origin new added-value products

• BSG is an agro-industrial by-product and is a source of various bioactive compounds

• Extraction methods have been applied to extract these compounds from BSG

• It is needed to find new techniques and new possible applications to the BSG

Keywords:

• Bioactive compounds
• brewer’s spent grain
• chemical composition
• extraction techniques

Acknowledgments

The authors would like to thank to the projects Co-promoção, NORTE-01-0145-FEDER-000004 and OCI-01-0145-FEDER-006684. Furthermore, the authors would also acknowledge the FCT projects UID/Multi/50016/2019, UID/BIO/04469/2013. The author T. Bonifácio-Lopes would also like to acknowledge the grant UMINHO/BD/11/2016.