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This paper details the results of a series of tests whose main purpose was to determinate how osmotic drying influences both water loss and color retention in cactus pear fruits. The dehydration process was performed using a 32 experimental design which involved three different sugar concentration levels (40, 50, and 60°Brix) and three different temperatures (25, 40, and 55°C). A product/solution ratio of 1/15, cactus pear cylindrical slices 5 mm thick, and ten-hour immersion time spans were used for all the experiments. Modeling of the drying curves was done with Fick%27s second law and Page%27s equation, which were used to calculate water effective diffusivity (D e), drying constant (k), and the b values respectively. The color parameters (L*, a*, b*) of the samples were measured before and after each test to evaluate total color change (ΔE). An analysis of variance (ANOVA) revealed that water diffusivity and Page%27s parameter b were affected by temperature and sugar concentration while the drying constant (k) was independent of the drying conditions. The total color change was affected only by the temperature. De and b values varied from 4.06×10-11 to 2.95×10-10 m2/s, and from 0.453 to 0.861 respectively. The best color retention was obtained at 25°C independent of the sugar concentration. Copyright © Taylor %26amp; Francis Inc.
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This paper details the results of a series of tests whose main purpose was to determinate how osmotic drying influences both water loss and color retention in cactus pear fruits. The dehydration process was performed using a 32 experimental design which involved three different sugar concentration levels (40, 50, and 60°Brix) and three different temperatures (25, 40, and 55°C). A product/solution ratio of 1/15, cactus pear cylindrical slices 5 mm thick, and ten-hour immersion time spans were used for all the experiments. Modeling of the drying curves was done with Fick's second law and Page's equation, which were used to calculate water effective diffusivity (D e), drying constant (k), and the b values respectively. The color parameters (L*, a*, b*) of the samples were measured before and after each test to evaluate total color change (ΔE). An analysis of variance (ANOVA) revealed that water diffusivity and Page's parameter b were affected by temperature and sugar concentration while the drying constant (k) was independent of the drying conditions. The total color change was affected only by the temperature. De and b values varied from 4.06×10-11 to 2.95×10-10 m2/s, and from 0.453 to 0.861 respectively. The best color retention was obtained at 25°C independent of the sugar concentration. Copyright © Taylor %26amp; Francis Inc.
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