Losses by diffusion of ascorbic acid during recycled water blanching of potato tissue

Ascorbic acid losses in potato cylinders in recycled and distilled water at 65degreesC, 80degreesC and 93degreesC for different periods of time were studied. As was found for distilled water, an increase in temperature of recycled water produced higher losses of ascorbic acid. The apparent diffusivities of ascorbic acid during blanching of potato in recycled and distilled water (water containing 2.6 kg m(-3) of soluble solids) show an Arrhenius-type equation. However, the estimated D-o and E-a values for distilled and recycled water were different, being 8.63 x 10(-6) m(2) s(-1) and 24.89 kJ mol(-1), respectively, for distilled water, and 5.14 x 10(-7) m(2) s(-1) and 17.09 kJ mol(-1) for recycled water. Then, the use of recycled water, besides saving energy and water costs and reducing the environmental impact, increases the ascorbic acid retention during the potato blanching. (C) 2002 Elsevier Science Ltd. All rights reserved.