30G-12 |
Air drying kinetics of osmodehydrated and calcium impregnated apple slices |
A. VALDEZ-FRAGOSO1, I. Perez-López2, V. Hernández-Landero2, A. López-Malo2, E. Palou2, H. Mújica-Paz1, and J. Welti-Chanes2. (1) Facultad de Ciencias Químicas, Universidad Autónoma de Chihuahua, Ciudad Universitaria, Chihuahua, 31170, Mexico, (2) Departamento de Ingeniería Química y Alimentos, Universidad de las Américas-Puebla, Santa Catarina Mártir, Cholula Puebla, 72820, Mexico Vacuum dehydration-impregnation by immersion process (DII) can be applied as a pretreatment in air drying of fruits. This process is very useful to prepare fruit products enriched in micronutrients and, due to the sugar uptake, to preserve the organoleptic and nutritional qualities during drying and subsequent storage. The aim of this study was to investigate the effect of calcium in apple slices, impregnated by a DII treatment, on drying kinetics of fruit at different temperatures. Apple slices were treated at 50 cm Hg vacuum pressure in osmotic solution containing sucrose (60 °Brix) and calcium (0 or 1000 ppm) using 3 and 24 min of relaxation and impregnation times, respectively. Fresh and osmodehydrated apples slices were dried in a pilot dyer at 60, 70 and 80 °C. Ca concentration was measured by atomic absorption spectroscopy. The moisture content of the samples was determined using the vacuum oven method. The air drying of untreated apple slices exhibited a constant rate period and two falling-rate periods. Drying of pretreated fruit was entirely in two falling-rate periods; the second falling rate period being considerable affected by the solid content in apple samples. At any studied temperature, the impregnated calcium has not effect on drying rate of apple slices. DII process under vacuum conditions improves the air drying process and allows to obtain better quality characteristics of the calcium-fortified apple slices.
Session 30G, Fruit & Vegetable Product: Processed Fruits and Vegetables
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