Valorisation of hop leaves for their bioactive compounds: Identification and quantification of phenolics across different varieties, crop years and stages of development

Calvert, Duncan; Dew, Tristan; Gadon, Arthur; Gros, Jacques; Cook, David

Abstract

Hop leaves, a by-product from hop cone harvesting, contain phenolic compounds of potential value for food or beverage applications. However, the abundant phenolics in hop leaves remain largely unquantified. This study quantified phenolics in hop leaves over two crop years, for three commercially significant varieties, at different developmental stages post-flowering. Ethanolic hop extracts were characterised using LC-ESI-qTOF-MS/MS and HPLC-DAD for the annotation and quantification of phenolics and bitter resins. Hop leaf phenolic profile exhibited considerable structural diversity, differing significantly from that of respective cones. Kaempferol/quercetin 3-O-glycosides and chlorogenic acids were the most abundant sub-groups with phenolic acids, procyanidins, prenylflavonoids and bitter resins also present. Phenolic profile was mainly variety-dependent with some crop year and developmental effects. Flavonol 3-O-glycosides were the main compounds driving varietal differences. Findings demonstrate the structural diversity and high concentrations of phenolic compounds in hop leaf extracts and their potential as a source of bioactives for valorisation.

Citation

Calvert, D., Dew, T., Gadon, A., Gros, J., & Cook, D. (2025). Valorisation of hop leaves for their bioactive compounds: Identification and quantification of phenolics across different varieties, crop years and stages of development. Food Chemistry, 465(Part 2), Article 142005. https://doi.org/10.1016/j.foodchem.2024.142005

• Journal Article Type: Article
• Acceptance Date: Nov 9, 2024
• Online Publication Date: Nov 12, 2024
• Publication Date: Feb 15, 2025
• Deposit Date: Dec 16, 2024
• Publicly Available Date: Dec 18, 2024
• Journal: Food Chemistry
• Print ISSN: 0308-8146
• Electronic ISSN: 1873-7072
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 465
• Issue: Part 2
• Article Number: 142005
• DOI: https://doi.org/10.1016/j.foodchem.2024.142005
• Keywords: Humulus lupulus L, Leaves, Phenolics, Valorisation, Agri-food co-products, LC-ESI-qTOF-MS/MS, HPLC-DAD
• Public URL: https://nottingham-repository.worktribe.com/output/42839561
• Publisher URL: https://doi.org/10.1016/j.foodchem.2024.142005
• Additional Information: This article is maintained by: Elsevier; Article Title: Valorisation of hop leaves for their bioactive compounds: Identification and quantification of phenolics across different varieties, crop years and stages of development.; Journal Title: Food Chemistry; CrossRef DOI link to publisher maintained version: https://doi.org/10.1016/j.foodchem.2024.142005; Content Type: article; Copyright: © 2024 The Authors. Published by Elsevier Ltd.