Estudio de la cinética de osmodeshidratación aplicando vacío en aguaymanto (Physalis peruviana L.)

Abstract

We studied the effect of temperature, osmotic concentration, acidity and vacuum pressure during the osmotic dehydration of Aguaymanto (Physalis peruviana L.). A syrup/fruit ratio of 4:1 was used during 180 minutes of the process making readings every 15 minutes. The variables studied significantly influenced moisture, water activity and b*. However, the soluble solids by effect of temperature, osmotic concentration and acidity; pH by effect of temperature and osmotic concentration; Acidity index by effect of temperature and acidity; L* by temperature and osmotic concentration; a* by effect of osmotic concentration. Three mathematical models were compared to describe the kinetics of water loss and the gain of solids at different temperatures (40, 50 and 60 °C), osmotic concentration (30, 40 and 50 °Brix), acidity (0.05, 0.075 and 0.1% citric acid) and vacuum pressure (200, 300 and 400 mmHg). Two empirical models were adjusted (Azuara and Peleg) and a phenomenological model from the solution of the second law of Fick. The results indicated that the model of Peleg adjusted better than the empirical model of Azuara and that to a lesser degree the phenomenological model of Fick, corroborated with the goodness of adjustment of the relative error mean percentage (ERM %) and the coefficient determination (R2). The highest water loss of 17.97 ± 2.23 % and the highest solid gain of 42 ± 3.06 °Brix were achieved under the following conditions; Temperature 60 °C, osmotic concentration 50 °Brix, acidity 0.075% and pressure 200 mmHg.