Upcycling walnut (Juglans regia L.) by-products: Characterisation of nutritionally relevant bioactive compounds
Background: Walnuts (Juglans regia L.) are attracting increasing interest from consumers, industry, and the healthcare community due to their high content of bioactive compounds, including (poly)phenols, carotenoids, tocopherols, and omega-3 fatty acids. Despite the continued growth in global walnut...
| Autores: | , , , , |
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| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2026 |
| País: | España |
| Institución: | Varias* (Consorci de Biblioteques Universitáries de Catalunya, Centre de Serveis Científics i Acadèmics de Catalunya) |
| Repositorio: | Recercat. Dipósit de la Recerca de Catalunya |
| OAI Identifier: | oai:dnet:recercat____::0a36f918c2556aff5161f650ca251c37 |
| Acceso en línea: | https://hdl.handle.net/2445/229186 |
| Access Level: | acceso abierto |
| Palabra clave: | Cuina (Nous) Fruita seca Polifenols Compostos bioactius Cooking (Nuts) Dried fruit Polyphenols Bioactive compounds |
| Sumario: | Background: Walnuts (Juglans regia L.) are attracting increasing interest from consumers, industry, and the healthcare community due to their high content of bioactive compounds, including (poly)phenols, carotenoids, tocopherols, and omega-3 fatty acids. Despite the continued growth in global walnut production, the effective valorisation of walnut processing by-products remains a challenge. While most research has focused on the edible kernel, emerging evidence suggests that underutilized walnut fractions may also represent valuable sources of compounds with antioxidant and anti-inflammatory properties. This study aimed to characterize the bioactive compound profiles of green walnuts, defective walnuts, and walnut shells in comparison to commercial whole walnuts and kernels. Methods: Samples collected from an orchard located in Huesca (Spain) were homogenized and analysed in triplicate. Proximate composition was performed following the official methods, fatty acid profile was determined by GC-FID, phenolic profile by UHPLC-ESI-MS/MS, and carotenoids and tocopherols by UPLC-DAD. Results: Green walnuts contained exceptionally high concentrations of carotenoids, especially β-carotene (629.7 ± 39.4 mg/kg). Walnut shells were the richest source of phenolic compounds, notably ellagic acid (713.3 ± 7.6 mg/kg) and catechin (71.9 ± 1.2 mg/kg). Tocopherols were mainly concentrated in the kernel, dominated by γ-tocopherol (226.9 ± 8.1 mg/kg), while defective walnuts showed a compositional profile similar to commercial walnuts. Conclusions: This comparative analysis highlights the significant potential of walnut processing by-products as sources of nutritionally relevant bioactive compounds. The findings support their valorisation as functional ingredients for agro-food and cosmetic applications within a circular economy framework. |
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