## 3 Results and Discussion
### Sensory Evaluation of Snacks Based on Undersized Kiwi  
The results of the sensory evaluation of snacks based on undersized kiwifruit for formulation A (with the addition of strawberry, fennel, and lemon juice), B (with the addition of fennel, juice, and peel, respectively, with lemon), and C (with the addition of fennel and spinach) are presented in Figures 5-7, respectively. The samples were characterized by the kiwifruit aroma with slightly perceptible other aromas from additional raw materials. The intensity of the aroma typical of kiwifruit was assessed by the panel in the range from 4.2 (for HA_s snack C) to 7.5 points (for FD snack C). Regardless of the type of snack, the intensity of the aroma typical of kiwifruit was the highest for dried fruit without the addition of a sweetener. Nevertheless, the addition of sucrose and trehalose reduced the characteristic aroma of kiwifruit. In the case of snacks B and C, those freeze-dried received higher points than those dried by hot air. The intensity of the flavor typical of kiwifruit in most cases (except for FD_s and HA_s samples of A formulation) was assessed, with higher scores yielded by the freeze-dried snacks compared to the hot-air-dried snacks. This is in line with the literature, according to which the freeze-drying process, unlike hot air drying, preserves the typical taste and aroma of the raw material [28].  
Figure 5: Sensory evaluation of snacks based on undersized kiwifruit for the formulation A: FD, freeze-dried snack; HA, hot-air-dried snack; s, with sucrose (2%); t, with trehalose (2%).  
Figure 6: Sensory evaluation of snacks based on undersized kiwifruit for the formulation B: FD, freeze-dried snack; HA, hot-air-dried snack; s, with sucrose (2%); t, with trehalose (2%).  
Figure 7: Sensory evaluation of snacks based on undersized kiwifruit for the formulation C: FD, freeze-dried snack; HA, hot-air-dried snack; s, with sucrose (2%); t, with trehalose (2%).  
The sweetness of the snacks, regardless of the drying method used and snack formulation was rated in a range from 3.0 (for HA snack C) to 6.7 points (for FD_s snack C). As expected, regardless of the drying method, snacks containing sucrose were the sweetest in comparison with those made using trehalose or without sweeteners. Trehalose is at least 50% less sweet than sucrose; therefore, the sweetness of the obtained snacks was also lower compared to the sucrose-sweetened snacks. In addition, the sweetness of trehalose is neutral, without a foreign aftertaste, and the time profile of its sweetness is longer, e.g., sweetness after consumption is felt by consumers longer than in the case of sucrose [40]. Similarly, the acidity was assessed inversely (except samples FD_s and FD_t of snack A and FD and FD_t of snack C). The snacks without sweeteners were considered the most acidic, while those with sucrose were considered the least acidic. At the same time, in snacks A, it was noticed that the freeze-dried snacks were characterized by a lower degree of acidity and a higher degree of sweetness (except for FD_t and HA_t) compared to the material dried using hot air. [PERSON] et al. [28] noted that in the sensory analysis of various types of freeze-dried fruit, some of them were assessed as much more acidic than before this process. This proves the complexity of the process of drying plant tissues.  
Furthermore, regardless of the composition, freeze-drying was characterized by higher crunchiness, while air-dried snacks were rather soft. This is linked to the high porosity of freeze-dried snacks. A similar structure was noted in freeze-dried snacks made from vegetable by-products with apple pomace [9], multilayer snacks made from different vegetables [23], and strawberry jelly [41]. The porous structure is attractive to consumers. However, less crunchy snacks were obtained through the use of hot air drying after the process resembling soft leather and it is considered a good method for obtaining healthy snacks [42].