Abstract
Fennel (Foeniculum officinale Mill. var. dulce Mill) is an annual aromatic plant of the Lamiaceae family. Its fruits are processed to obtain essential oil for use in the food industry and cosmetics. The physical parameters of the fruits, i.e. length (5.50-8.00 mm), width (1.50-2.00 mm), volume of 100 fruits (1.36 × 10(-6) m(3)), density of 100 fruits (935.82 kg/m(3)), average volume of one fruit (1.36 × 10(-8) m(3)), average equivalent diameter of one fruit (2.96 mm), angle of repose, stainless steel (from 16 to 22°), angle of repose, black steel (from 19 to 28°), angle of repose, plywood (from 18 to 24°), and their chemical parameters, i.e. moisture (13.49%), ash (6.49%), protein (18.25%), essential oil (8.38%), vegetable oil (10.52%), and total carbohydrates (51.04%) were determined for the fruits. The adsorption and desorption isotherms of the fennel fruits were obtained using the static gravimetric method at two temperatures, 20 and 40 °C. The Halsey model provided a good description of the sorption isotherms, which were of type II according to Brunauer's classification. The increase in the temperature led to a significant decrease in the monolayer moisture. The contamination on the fruit surface at three relative humidities (0.43, 0.59, and 0.76) at 20 °C was determined.