## 3 Results and Discussion
### Physicochemical Properties
pH is an important factor for the production of safe, quality and value-added food. The pH of foods plays an important role in determining the extent of heat treatment required to ensure a safe final product. pH also has an impact on color pigments [38]. [PERSON] and [PERSON] [37] found that the pH values of beef patty samples that replaced animal fat with almond flour increased with the cooking process. Similarly, [PERSON] et al. [29] reported higher pH values in chicken burgers with silverskin after cooking. The effect of treatment \(\times\) production stage interaction on the pH value of chicken patties is shown in Figure 3.  
The highest pH value was determined in the control sample before cooking, while the highest average values after cooking were observed in the control and SS1 samples. The highest increase in pH after cooking was observed in the sample with 2% CSS, followed by samples with 4% and 6% CSS, respectively. Using CSS instead of animal fat in chicken patty production significantly affected the moisture content and aw values (\(p\) < 0.01). The replacement of animal fat with CSS decreased the moisture content and a\({}_{\text{w}}\) values of chicken patties. These results may be due to the addition of CSS, which has a relatively low moisture content of 2.78% reported by [PERSON] et al. [2], and 7.1% reported by [PERSON] et al. [14]. In addition, it has a relatively low a\({}_{\text{w}}\) value of 0.32 reported by [PERSON] et al. [2] and 0.20 reported by [PERSON] et al. [14]. While the highest average values were determined in the control group, the lowest average values were observed in the SS3 group with 6% CSS (\(p\) < 0.05). Lower moisture content and aw in chicken patties with CSS was probably due to the increase in solid content by dry CSS, which was used in this study having lower moisture content than animal fat. Similar results were reported by [PERSON] and [PERSON] [8] in cakes with different levels of CSS addition as a fat replacer and by [PERSON] et al. [27] in yogurt with CSS addition. However, [PERSON] et al. [29] found that adding 1.5% or 3% CSS to chicken burgers did not significantly affect the moisture content and aw values. The cooking process was found to have a significant effect on the moisture content and aw values of chicken patties (\(p\) < 0.01). There was a statistical difference between the average moisture content and aw values before and after cooking, with lower average values obtained after cooking (Table 2). This may be attributed to the moisture loss that occurs during cooking. Similar results were reported by [PERSON] et al. [39] in beef burgers with the addition of cocoa bean shells. The effect of treatment \(\times\) production stage interaction on the moisture content of chicken patties is shown in Figure 4.  
Figure 3: Changes in pH values of chicken patties during the production stages (Control: 12% fat, SS1: 10% fat + 2% silverskin, SS2: 8% fat + 4% silverskin, SS3: 6% fat + 6% silverskin). a–c: Means marked with different letters in different formulations at the same production stage are statistically different from each other (\(p\) < 0.05). The highest moisture content was observed in the control group before cooking, while after cooking, the highest average values were found in the control and SS2 groups. After cooking, the moisture content decreased in all groups, with the lowest value determined in the SS3 group with 6% CSS. Moisture retention is crucial for the taste of food and the preparation, processing, and storage of food. In chicken patties, the replacement of animal fat with CSS significantly influenced the moisture retention capacity (\(p<0.01\)), and higher average moisture retention capacity values were observed in the groups with CSS compared to the control group (\(p<0.05\)). However, no significant difference was observed among the groups with CSS. The high moisture retention capacity may be attributed to the high dietary fiber content (approximately 62.4%) of CSS [40].