Global beer production generates large volumes of by-products, including hot trub, a solid residue formed during wort boiling. Although traditionally considered waste, hot trub represents a complex matrix rich in denatured proteins, hop-derived polyphenols, and yeast residues, indicating promising potential for the recovery of bioactive compounds. Previous studies have mainly focused on the chemical composition and technological valorization of brewing by-products. However, to the best of our knowledge, very limited information is available regarding the biological activity of hot trub, particularly its antioxidant potential. This study aimed to characterise the phytochemical profile of hot trub extracts obtained in the presence (Ty) or absence (T) of yeast and to evaluate their cytotoxicity and antioxidant activity using a human intestinal epithelial cell model (Caco-2). HPLC/MS analysis revealed a wide range of bioactive compounds, including organic acids, flavonoids (e.g. catechin and myricetin), tocopherols (α and β), and carotenoids. Methanolic and ethanolic extracts exhibited greater phytochemical diversity than aqueous extracts. Quantitative assays (Folin–Ciocalteu, DPPH, and FRAP) confirmed significant antioxidant capacity, particularly in yeast-containing (Ty) samples and alcoholic extracts. Biological assays demonstrated that the extracts were not cytotoxic to Caco-2 cells at the tested concentrations. Moreover, both pre-treatment and co-treatment with trub extracts significantly reduced intracellular reactive oxygen species (ROS) accumulation and protected cells against tert-butyl hydroperoxide (TBH)-induced oxidative stress and loss of viability, with Ty extracts showing the highest protective efficacy. This is the first study to provide comprehensive cellular-level validation of hot trub's antioxidant potential, indicating that hot trub is a valuable and low-cost source of bioactive compounds capable of counteracting oxidative stress at the cellular level. The valorisation of this brewing by-product may support the development of functional foods and nutraceuticals while enhancing sustainability and circular economy strategies within the brewing industry.
Antioxidant-rich extracts from beer hot trub counteract oxidative stress in Caco-2 cells
Giardina M.;
2026-01-01
Abstract
Global beer production generates large volumes of by-products, including hot trub, a solid residue formed during wort boiling. Although traditionally considered waste, hot trub represents a complex matrix rich in denatured proteins, hop-derived polyphenols, and yeast residues, indicating promising potential for the recovery of bioactive compounds. Previous studies have mainly focused on the chemical composition and technological valorization of brewing by-products. However, to the best of our knowledge, very limited information is available regarding the biological activity of hot trub, particularly its antioxidant potential. This study aimed to characterise the phytochemical profile of hot trub extracts obtained in the presence (Ty) or absence (T) of yeast and to evaluate their cytotoxicity and antioxidant activity using a human intestinal epithelial cell model (Caco-2). HPLC/MS analysis revealed a wide range of bioactive compounds, including organic acids, flavonoids (e.g. catechin and myricetin), tocopherols (α and β), and carotenoids. Methanolic and ethanolic extracts exhibited greater phytochemical diversity than aqueous extracts. Quantitative assays (Folin–Ciocalteu, DPPH, and FRAP) confirmed significant antioxidant capacity, particularly in yeast-containing (Ty) samples and alcoholic extracts. Biological assays demonstrated that the extracts were not cytotoxic to Caco-2 cells at the tested concentrations. Moreover, both pre-treatment and co-treatment with trub extracts significantly reduced intracellular reactive oxygen species (ROS) accumulation and protected cells against tert-butyl hydroperoxide (TBH)-induced oxidative stress and loss of viability, with Ty extracts showing the highest protective efficacy. This is the first study to provide comprehensive cellular-level validation of hot trub's antioxidant potential, indicating that hot trub is a valuable and low-cost source of bioactive compounds capable of counteracting oxidative stress at the cellular level. The valorisation of this brewing by-product may support the development of functional foods and nutraceuticals while enhancing sustainability and circular economy strategies within the brewing industry.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
