Processing Strategies for Extraction and Concentration of Bitter Acids and Polyphenols from Brewing By-Products: A Comprehensive Review

Annually, 221 million tons of agro-food by-products are generated worldwide, causing diverse environmental issues due to incorrect discharge. Hot trub, spent hops, brewer’s grains, and yeast the produced in beer manufacturing chain. These contain fibers, proteins, polyphenols, essential oils, taste compounds, presenting high possibilities use as alternative raw materials. In this review, we compiled knowledge gaps brewing by-product reuse, from phytochemical compound extractions concentration approaches, mainly concerning bitter acids polyphenols. Moreover, assessed discussed emerging technologies solvents that have allowed for higher extraction yields. We illustrated importance purification steps non-destructive methods added value products reuse approaches. Finally, showed relevance scale-up economic feasibility studies order encourage implementation facilities produce polyphenols sources such hot trub hops.