## 3 Results and Discussion
### Multi-Objective Optimization
However, for these solutions, EC, CD, A\({}_{\text{loss}}\), TAC\({}_{\text{loss}}\), TFC\({}_{\text{loss}}\), TPC\({}_{\text{loss}}\) are respectively about 2.9, 1.7, 1.7, 2.2, 8.6, and 2.5 times higher than their minimum values. CD was always conflicting with other quality parameters (see Figure 4b). Assuming that the temperature and velocity of the drying air can be set (in the dryer) with an accuracy of 0.5 \({}^{\circ}\)C and 0.02 m/s, drying at \(T_{d}\) = 45.5 \(\pm\) 0.5 \({}^{\circ}\)C and \(v_{d}\) = 0.5 \(\pm\) 0.02 m/s allows for obtaining _Echium amoneum_ petals with the following parameters: TAC\({}_{\text{loss}}\), TFC\({}_{\text{loss}}\), A\({}_{\text{loss}}\), TPC\({}_{\text{loss}}\), CD, EC: 36.6%, 43.3%, 60.0%, 47.9%, 33.6, and 702.3 MJ/kg, respectively (average values for mentioned ranges of \(T_{d}\) and \(v_{d}\)). Dried petals with low A, TAC, TFC and TPC losses also cannot be obtained with the least energy expenditure. For the obtained solutions (for EC\({}_{\text{min}}\)), A\({}_{\text{loss}}\), TAC\({}_{\text{loss}}\), TFC\({}_{\text{loss}}\) and TPC\({}_{\text{loss}}\) are as follows: for ID134: 45.7%, 49.4%, 27.5%, 30.8%, for ID132: 46.6%, 48.9%, 27.1%, 32.2%, and for ID131: 47.1%, 48.5%, 26.9%, 32.7%, respectively. Therefore, these values are about 1.2, 3.1, 4.0, and 1.5 times higher than the lowest values, respectively, whereas for A\({}_{\text{loss}}\)\({}_{\text{min}}\), TAC\({}_{\text{loss}}\)\({}_{\text{min}}\), TFC\({}_{\text{loss}}\)\({}_{\text{min}}\), and TPC\({}_{\text{loss}}\)\({}_{\text{min}}\), the energy consumption is 434.8 (ID92: \(T_{d}\) = 53.94 \({}^{\circ}\)C, \(v_{d}\) = 1.00 m/s), 1344.3 (ID1: \(T_{d}\) = 40.00 \({}^{\circ}\)C, \(v_{d}\) = 0.60 m/s), 666.3 (ID 26: \(T_{d}\) = 50.59 \({}^{\circ}\)C, \(v_{d}\) = 1.00 m/s) and 507.5 MJ/kg (ID62: \(T_{d}\) = 60.00 \({}^{\circ}\)C, \(v_{d}\) = 0.58 m/s), respectively. For TAC\({}_{\text{loss}}\) Pareto front (Figure 4a) indicates solutions ID54, ID55 and ID69, for which EC is 526.0, 520.2, and 456.2 MJ/kg, while TAC\({}_{\text{loss}}\) is 31.9, 32.0, and 33.2%, respectively. These solutions are obtained for the following drying process parameters: air drying temperature 59.94, 60.00, and 53.35 \({}^{\circ}\)C, and air-drying velocity 0.65, 0.61, and 1.00 m/s. However, for these solutions, EC is 1.9, 1.9, and 1.6, CD 2.0, A\({}_{\text{loss}}\) is 1.3, 1.3, and 1.0, TAC\({}_{\text{loss}}\) is 4.5, 4.6, and 2.1, TFC\({}_{\text{loss}}\) is 4.6, 4.6, and 1.26, and TPC\({}_{\text{loss}}\) 1.1, 1.0, and 1.8 times higher than their minimum values. Therefore, ID69 is better than ID54 and ID55 from the EC, A\({}_{\text{loss}}\), TAC\({}_{\text{loss}}\), and TPC\({}_{\text{loss}}\) point of view. Assuming the mentioned accuracy of \(T_{d}\) and \(v_{d}\) setting, drying at \(T_{d}\) = 53.5 \(\pm\) 0.5 \({}^{\circ}\)C and \(v_{d}\) = 1.0 \(\pm\) 0.02 m/s (parameters from ID 69) allows for obtaining _Echium amoneum_ petals with the following parameters: TAC\({}_{\text{loss}}\), TFC\({}_{\text{loss}}\), A\({}_{\text{loss}}\), TPC\({}_{\text{loss}}\), CD, EC: 35.0%, 9.0%, 39.1%, 37.7%, 38.3, and 445.5 MJ/kg, respectively (average values for mentioned ranges of \(T_{d}\) and \(v_{d}\)). For A\({}_{\text{loss}}\) Pareto front (Figure 4d), solutions are indicated for ID134 and ID116, for which EC is 278.2, and 410.3 MJ/kg, while A\({}_{\text{loss}}\) is 45.7 and 39.6%, respectively. These solutions are obtained for the following drying process parameters: air drying temperature 60.00 and 55.12 \({}^{\circ}\)C, and air-drying velocity 0.50 and 1.00 m/s. However, for these solutions, EC is 1.0 and 1.5, CD is 1.9 and 2.0, A\({}_{\text{loss}}\) is 1.2 and 1.0, TAC\({}_{\text{loss}}\) is 3.2 and 2.8, TFC\({}_{\text{loss}}\) is 4.0 and 1.7, and TPC\({}_{\text{loss}}\) is 1.5 and 1.7 times higher than their minimum values. Therefore, ID116 is better than ID134 from the TFC\({}_{\text{loss}}\) point of view.