## 3 Results and Discussion
### Sensory and Physicochemical Analysis of Fruit Juice Formulations
However, for some persons, some blended juice variants were rated lower because they were more tart in taste. For variants AB4 and AB5, as many as 12 people thought so, and for variants AB3 and AC5, 7 and 5 people, respectively. A higher proportion of rose hips resulted in more tart mixed juices. In the assessment of the taste (sweet, sour, tart) of mixed juices, the highest acceptance scores were given to the AC1 formulation of mixed rose-apple juice (50% rose and 50% apple juices) and to the AC2 formulation of mixed rose-apple (60% rose and 40% apple juices). These juices received the highest sensory scores for sweetness, tartness, and sourness (the most sweet--4.43 and 4.16, the least tart--3.5 and 3.32, and the least sour--4.73 and 4.43 for AC1 and AC2 juice, respectively). The last tested attribute, which theoretically includes all the previously discussed features, is the overall impression. It shows that the AC1 variant of the mixed juice was the best, and the AB5 variant of the juice was the worst. Cluster analysis (Figure 1) and regression analyses were performed to determine which of the assessed features of mixed juices have the greatest impact on shaping the overall impression of mixed juices. The cluster analysis showed a high similarity between sweet and sour taste, but also between the overall impression and the colour of the tested juices. A division of features into two groups was also observed. The first group included features such as tart, sweet, and sour taste, and the second group included other sensory features. Regression analysis of sweet and sour taste explained 73.99% of the variability for the overall impression, and regression analysis of sweet, sour, and tart taste as well as aromatic and fruity odour explained 68.92% of the variability in the overall impression. The pH values of the single-component juices were in the range of 4.34 \(\pm\) 0.02 (B), 3.60 \(\pm\) 0.03 (C), and 3.45 \(\pm\) 0.03 (A), while the total acidity values were in the range of 1.40 \(\pm\) 0.02 (A), 1.28 \(\pm\) 0.03 (C), and 0.48 \(\pm\) 0.03 (B) g citric acid/100 mL. In the research conducted by [PERSON] et al. [32], it can be seen that both pH and other qualitative factors depend on the type of raw material and its variety and therefore the results may differ significantly for one species. The pH of the strawberry, apple, and rose juices were similar to those reported by other authors [33; 34; 35; 36]. The pH values of the formulations of mixed juices were in the range of 3.96-3.70 (rose-strawberry juices) and 3.58-3.47 (rose-apple juices), while the total acidity values were in the range of 0.94-1.24 (rose-strawberry juices) and 1.28-1.36 (rose-apple juices) g citric acid/100 mL. The addition of a higher concentration of rose juice resulted in mixed juices with lower pH values and higher total acidity (\(p<0.05\)), which was related to the lower pH (3.45) and higher acidity (1.40 g citric acid/100 mL) of rose juice compared to strawberry juice and apple juice. It is known that pH is a very important parameter affecting the microbiological conservation [37]. All mixed juices had a pH below 4.5, which allows them to be classified as acidic foods that limit the growth of microorganisms. However, it should be remembered that too much acidity of the juice may change the taste of the juice and reduce its sensory preference, as consumers may not accept products with too much acidity [38]. The total soluble solids in fruits mainly contain sugars and acids, dissolved vitamins, fructans, proteins, pigments, phenolics, and minerals [39]. The rose juice presented higher TSS content (21.6 \({}^{\circ}\)Brix) than the strawberry (9.1 \({}^{\circ}\)Brix) and apple (13.2 \({}^{\circ}\)Brix) juices or the mixed juices (15.8-20.9 \({}^{\circ}\)Brix for the rose-strawberry juices; 17.7-21.1 \({}^{\circ}\)Brix for the  
Figure 1: Cluster analysis for individual consumer evaluation attributes. Abbreviations: COL—Colour; AROO—Aromatic odour; FRUO—Fruity odour; SWET—sweet taste; SOUT—sour taste; TART—tart taste OVI—Overall impression.