This work had as main objective to recover bioactive compounds, more specifically phenolics, from cider lees using subcritical water, an environmentally benign fluid. Maximum solubilisation was obtained at 150ºC for 30 minutes, and a decrease is observed at higher temperatures, indicating the occurrence of precipitation. Maximum total phenolic content (FCR) was obtained at 220ºC for 10 minutes. Chlorogenic acid was identified as the major phenolic in cider lees, however at 220ºC for 10 minutes, only trace levels were found, therefore the high total phenolic content should be the result of interactions between phenolics and macromolecules present in solution. Sequential subcritical water was employed to reduce complexity of extracts produced. Maximum antioxidant capacity (FCR, ORAC) was obtained at 120ºC and 220ºC, where at 120ºC is due to cider phenolics while at 220ºC, after the removal of most of the compounds, it is only left cell wall carbohydrates and chitin, which should be responsible for the formation of derivatives with high antioxidant capacity. Cyclodextrin was used to improve oxidative stability of the cider lees extracts, however while it improved the oxidative stability for cider lees extracts obtained at low temperatures, to cider lees extracts obtained at higher temperatures, no improvement was registered.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:655787 |
| Date | January 2015 |
| Creators | Carapetudo Antas, Fábio Tomé |
| Publisher | University of Birmingham |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://etheses.bham.ac.uk//id/eprint/5994/ |
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