Calcium fortification of vegetables by applying vacuum impregnation (VI) is an alternative in developing functional foods. Nevertheless, calcium ions can interact with the plant tissue, modifying its mechanical and vacuum impregnation responses. These effects were studied in eggplant, oyster mushroom and carrot samples. Sample VI was carried out with isotonic solutions containing (i) sucrose and calcium lactate and (ii) sucrose. From the analysis of sample impregnation and deformation levels, the slight influence of Ca presence on the impregnation behaviour of these products could be concluded. Nevertheless, mechanical behaviour of eggplant and carrot were notably affected by calcium, although no significant effects were observed in oyster mushroom (without pectin in their cell architecture). Energy dispersive X-ray microanalysis (EDXMA) in impregnated products showed that calcium impregnation occurs in the intercellular spaces of eggplant and oyster mushroom and in xylem of carrot. (C) 2002 Elsevier Science Ltd. All rights reserved.