## 3 Results and Discussion  
### Energy Value of Freeze-Dried Vegetable-Based Products  
The energy value is strongly correlated with the nutrient content. For this reason, the concept of nutritional value is commonly referred to as energy content and essential nutrients. More precisely, the nutritional value determines the suitability of food products to meet the body's metabolic needs. The degree of nutrient utilisation is influenced by their balance, digestibility, and bioavailability. It is plausible that products with a diversified composition and containing various nutrients have a higher nutritional value [42; 43; 44; 45]. There is also a relationship: the more the product contains more nutrients and the more these nutrients are absorbed by the human body, the greater the nutritional value of the product [44; 45; 46; 47].  
Figure 1 shows the average energy value of freeze-dried plant products produced with the use of vegetables and hydrocolloids. The values are presented in terms of 10 g of finished products, which is one snack portion. The energy value of the individual flavour variants was quite even and ranged from 14.5-16.5 kcal/10 g portion of the finished product. At the same time, no significant differences were found, regardless of the reformulation of the composition and the hydrocolloid used for producing snack bars. All products belong to the same homogeneous group. Bars: 3--\(\rm CPCB_{A}\) and 4--\(\rm CPCB_{G}\) had the highest energy value: 15.990 and 16.150 kcal/10 g, respectively. On the other hand, bars: 1 and 2 were characterised by the lowest energy value of 14.703 and 14.863 kcal/10 g, respectively.  
The differences in the energy value for individual bar compositions are determined by the content of individual vegetables, the highest of which, according to the Regulation (EU) No. 1169/2011 of the European Parliament and of the Council of 25 October 2011 [42], are characteristic of corn and potatoes. The content of those ingredients in the bars obtained, irrespective of the hydrocolloids used, amounts to about 20% in total in samples 1 and 2,around 60% in samples 3 and 4, and around 48% in samples 5 and 6, which results in a different energy value of the finished products (Table 1; Figure 1).  
Manufactured by [PERSON] et al. [31], extruded cereal and vegetable snacks, including cereal-pumpkin and cereal-zuechini-broccoli, had an average energy value of 22.8 kcal per 10 g of product. Those values were slightly higher than those obtained in this study for presented bars with hydrocolloids.  
In comparison, freeze-dried bars available in the market of the \"Frupp\" brand, made from fruit, have a higher energy value than the investigated vegetable bars. For example, a bar of apple (36 kcal), passion fruit and apple (34 kcal) and product to which a vegetable was added (banana, carrot, passion fruit) (37 kcal) [48]. Comparable energy value is also seen in fruit and nuts made by the \"Farmer\" company, which offer the flavour of spinach with lemon (36.7 kcal/10 g), tomato (35 kcal/10 g), and beetroot with garlic (34 kcal) [49]. \"Foods by Ann\" with dried strawberry and beetroot, presented as an ideal snack before exercise, and its energy value is 42.71 kcal per 10 g, is characterised by a higher calorific value among market vegetable bars [50].