The effects of vacuum pressure and its application time on the volume of isotonic solution (IS) impregnated in slices of mango, apple, papaya, banana, peach, melon, and mamey were studied using response surface methodology. Fruits were subjected to vacuum impregnation (VI) treatments using sucrose IS. VI times between 3 and 45 min and vacuum pressures (VP) between 135 and 674 mbar were applied. Second order polynomials were developed to estimate the volume of IS impregnated in each fruit (R-2 > 0.870). VP had a significant effect (p less than or equal to 0.10) on the volume of IS impregnated in fruit slices of all the studied fruits. The impregnation also depended significantly (p less than or equal to 0.10) on the VI time, except for apple. Under the studied conditions, the effective porosity values of the fruits varied from 0.016 for mamey to 0.330 for apple. (C) 2002 Elsevier Science Ltd. All rights reserved.