The kinetics of moisture loss and solids gain during osmotic dehydration of blueberries under different conditions of temperature (37--60°C), concentration of the sucrose solution (47--70°Brix) and contact time between fruit and sucrose solution (0.5--5.5 h) were studied, and modeled based on Fick's law of unsteady state diffusion. The rates of moisture loss and solids gain were also related to temperature and sucrose concentration. / The second stage convective drying behavior of osmo-dehydrated blueberries was evaluated in a forced air cabinet dryer (temperature: 50°C, relative humidity: 14%, air velocity: 0.6 m/s) with a cross-flow tray arrangement. Osmotic dehydration pre-treatments included different combinations of temperature, sucrose concentration and contact time. Fick's second law of unsteady state diffusion was used to model the air drying kinetics. / The quality of two-stage osmo-convective dried blueberries with respect to color, texture and rehydration ratio was evaluated. The parameters analyzed for color were the total color difference (DeltaE) and, the (a/b) ratio as the indicator for the red-blue color. The texture analysis included evaluation of the hardness, chewiness and stickiness of the osmo-convective dried blueberries. (Abstract shortened by UMI.)
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.20602 |
| Date | January 1997 |
| Creators | Nsonzi, Frances. |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Master of Science (Department of Food Science and Agricultural Chemistry.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001608839, proquestno: MQ44236, Theses scanned by UMI/ProQuest. |
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