Photo-degradation of alfalfa saponins by UV–visible multi-wavelength irradiation
A photochemical treatment with UV multi-wavelength irradiation was applied to investigate the degradation of the saponins mixture obtained from alfalfa leaves. The photo-degradation was studied in an aqueous solution at a pH range of 4–7 and temperature range of 20–80 °C. The samples were irradiated...
| Authors: | , , , |
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| Format: | article |
| Status: | Published version |
| Publication Date: | 2022 |
| Country: | España |
| Institution: | Universitat de Lleida (UdL) |
| Repository: | Repositori Obert UdL |
| OAI Identifier: | oai:repositori.udl.cat:10459.1/72633 |
| Online Access: | https://doi.org/10.1016/j.lwt.2021.112809 http://hdl.handle.net/10459.1/72633 |
| Access Level: | Open access |
| Keyword: | Alfalfa UV irradiation Saponin Kinetic Alfals Cinemàtica |
| Summary: | A photochemical treatment with UV multi-wavelength irradiation was applied to investigate the degradation of the saponins mixture obtained from alfalfa leaves. The photo-degradation was studied in an aqueous solution at a pH range of 4–7 and temperature range of 20–80 °C. The samples were irradiated for 80 min using a mid-pressure mercury lamp with emission wavelengths between 250 and 740 nm. The dependence of the absorbed radiation on the concentration of alfalfa saponins was evaluated, and a linear dependence was found for the range of concentrations experimented throughout the photo-degradation. The alfalfa saponins mixture absorbed radiation between 470 and 610 nm with a maximum absorption peak at 543 nm. This means that any lamp emitting within this wavelength range could produce some degree of photo-degradation. A reaction mechanism was proposed, matching the experimental pseudo-first-order kinetic model that best fitted the evolution of the saponins mixture concentration. The photo-degradation rate was found to increase with increasing temperature and decreasing pH value, causing a reduction of 80% in the concentration of the alfalfa saponins mixture after 80 min at pH 4 and 80 °C. |
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