## 3 Results
### Statistical Analysis of the Tested Properties of Supplemented Crisps  
The similarity of corn snacks with fruit additives with regard to their physical properties was analyzed in order to compare snacks produced on the basis of different fruit variants and their amount in the mixtures prepared for the end product production. Herein, a multidimensional cluster analysis was performed. As in most categories, the tested features do not differ between different speeds of the screw in the extruder, they were averaged with regard to the screw speed factor. The analysis, however, omitted the features of hardness and cutting force, as they showed variations therein, as well as the feature of fracturability, as it was characterized by many outliers. In order to prevent inaccuracies in the interpretation of the results, the data were subsequently standardized, thus freeing them from the different utilized units employed to describe the studied features. In order to generate the dendrogram (Figure 2), we applied the Ward minimum variance classification algorithm, with the Euclidean distance being employed as a measure of similarity. As a result of the cluster analysis, corn snacks containing various combinations of the factors \"fruit type, share amount\" were divided into 2 groups (clusters). A smaller group (Figure 2, lower part of the graph) incorporates corn crisp end-products obtained through the addition of 15 or 20% of apple, white mulberry and goji berry powders to the base corn grit material. They are similar in color and have a similar expansion index, which results from the small aeration of the crisps and the negligible porosity of the structure. It can therefore be assumed that from the point of view of the tested characteristics (\(L^{*},a^{*},b^{*}\), BD, EI, WAI, WSI, CR), the crisps obtained as a result of these combinations have very similar properties and would probably be indistinguishable for the consumer. Figure 2: Dendrogram of similarity of the tested supplemented corn-based crisps with factors “fruit type, share amount”. Results of this study demonstrates that, while type and amount of fruit additives affects the tested physical properties of the final product, from the buyer's point of view, some combinations of fruit additives and their shares may seem indistinguishable. It turns out that the buyers are not able to distinguish between the combinations of blackberry 10% and blackberry 15%; elderberry 10% and 15%; and apple 5% and white mulberry 5%. The dendrogram shows that the combinations of blackberry 10% and blackberry 15% are the most homogeneous in terms of the examined features; while elderberry holds a share of 10% and 15%, and apple and white mulberry indicate a share of 5% in both cases. Therefore, from the point of view of the production process, taking into account economic factors, it can be recommended to resign from the production of corn crisps incorporating blackberry and elderberry powders in the amounts of 15% and mulberry powders in the amounts of 5%. What is more, when comparing the content of 10% and 15% of fruit, a snack with a 15% share has less taste. In addition, production of snack items with higher fruit contents are more difficult due to the higher vegetable fiber contents, and, consequently, decreasing process efficiencies. Moreover, regarding crisps containing powdered apple and crisps containing powdered white mulberry, consumers will more often reach for what is familiar, i.e., those with the addition of apples. Freeze-dried apple slices are very popular, and gluten-free snacks with these fruits can become a modern version of classic crisps. k-means clustering (in this case k = 2) revealed that the combinations of the factors \"fruit type, share amount\" that formed the first cluster, are the basis of determining the suitability of production of extruded crisp items containing fruit. Herein, the bulk density and friability are below the value average, and the expansion index, WAI and WSI are above the average (Figure 3).