OSMOTIC DEHYDRATION OF PAPAYA - EFFECT OF SYRUP CONCENTRATION

The present study was carried out to determine the effects of sucrose syrup concentration (50, 60 and 70% w/w) in a static system with 1:2 f ruit:syrup ratio, and of the circulation of a 60% (w/w) syrup with a 1 :20 fruit/syrup ratio to maintain constant the concentration on the di ffusional coefficients (D) involved in the mass transfer phenomena, du ring the osmotic dehydration of infinite slabs of papaya. The D values were evaluated using Fick's second law. The water removal (WR) with s yrups of 50, 60 and 70% showed two velocity periods, while the solid u ptake (SU), in terms of Brix degrees, showed only one. In general, the D values were higher for WR than for SU, and increased as the syrup c oncentration increased. With the constant syrup concentration, the D v alue for WR in the second velocity period was about 25% higher (0.926 x 10-(10) m2. s-1), and for SU was about 16% lower (0.748 x 10(-10) m2 .s-1) than those obtained in the static case. The results in terms of WR and SU, showed that the treatment with a constant syrup concentrati on was the best of all tested.