Changes in calcium level and mechanical properties of apple tissue due to impregnation with calcium salts

The purpose of this paper was to analyze the ability of apple matrix for calcium incorporation by two different impregnation techniques (in vacuum or at atmospheric pressure) and to determine the effect of these treatments on material compression behavior. According to the operative pressure, calcium incorporated in 200 g of fruit would satisfy about 23–62% of the Adequate Intake for adults. The greatest calcium content (3100 ppm) was reached after 22 h atmospheric impregnation process, while the calcium amount incorporated during vacuum treatment was similar to the one obtained after ≅10 h atmospheric process. Calcium impregnated tissues exhibited different response to compression as compared with raw fruit, showing a decrease in the values of failure force and modulus of deformability.