## 3 Results and Discussion  
The pH value has an impact on many quality parameters, such as water holding capacity, tenderness, color, juiciness, flavor, aroma, protein proteolysis concentration and shelf life. The pH of a meat product was measured after production (day 0). The pH values of the samples varied from 5.95 to 5.78 (Table 2). Differences in pH values across samples with GRFP addition were observed. Samples with GRFP were added, characterized by lower pH value than control (A). This indicates that the addition of GRFP significantly decreases pH values. This can be attributed to the accumulation of acidic products from the added fruits. A similar effect was observed in the study [PERSON] et al. [15], which indicated that the addition of dried cloves, cinnamon, oregano and mustard extracts to raw chicken meat decreased the pH values of samples during storage. According to the authors, this effect could be connected with growth of bacteria (bacteria's metabolized amino acid, which are released during the breakdown of proteins). [PERSON] et al. [16] showed that a low guelder rose fruit's pH is 2.95. Our study indicated that GRFP's total acid content amounts to 1.78 g/100 g. Thus, the addition of GRFP affects the pH of meat products in this study. In their study, [PERSON] et al. [17] observed that, due to the lower value of pH of marinatedpultry meat, the L* value was higher and meat was lighter. In our study, the HMP with a lower pH value (with GRFP addition) was not lighter. The cooking loss of control samples was determined at 8.71% and it was significantly (\(p\leq 0.05\)) lower than in the experimental samples containing lyophilized GRFP (26.14-26.24%). The samples (B, C and D) were no different in their values of cooking loss. An increase of cooking loss, along with increasing addition of the plant component, was also observed in the study conducted by [PERSON] et al. [18]. The addition of Polygonum cuspidatum and rosmary extract (dose 148 mg/kg, expressed as gallic acid equivalent) caused cooking losses determined to be 26.85%. The addition of lyophilized fruits with a low pH value results in the highest cooking loss. This occurrence a consequence of the protein denaturation, which caused the decreased ability of meat emulsion to bind water and fat. Cooking loss is an important issue that concerns the quality of meat, as well as economic aspects [19]. In further research, attempts will be made to offset the problem of high cooking loss and design certain solutions, e.g., the use of freeze-dried encapsulation and addition to meat products. The applied additives (\(p\leq 0.05\)) resulted in a decreased value of profile texture parameters (Table 3). A significant dependence was found between the level of the addition of GRFP and gumminess and chewiness. Meat products with GRFP were characterized by lower gumminess and chewiness than those in the control sample (A). Some studies found meat samples immersed in acid marinades characterized by lower hardness than control samples, which may be related to a decrease of water-binding capacity of meat proteins [17]. However, in our study, the hardness values of HMP samples produced without GRFP and samples produced with the highest addition GRFP did not differ statistically. Further research is needed to draw conclusions and possibly address discrepancies in results, as well as to learn about the relation between guelder rose fruit constituents and meat batter ingredients. The results of color parameters (average values) are shown in Figure 2. In control sample A, the highest mean L* values were observed and they increased during the storage period from 77.12 \(\pm\) 0.83 (day 0) to 79.04 \(\pm\) 2.71 (day 14). In a similar effect obtained in the study by [PERSON] et al. [20], the control samples showed higher L* values than samples treated with rosm