# Changes in Quality Features of Pork Burgers Prepared with Chokeberry Pomace During Storage
## 3 Results and Discussion
### pH Value of Pork Burgers During Storage
A significant effect (\(p<0.05\)) was observed for both burger treatment and storage time on the L* parameter; however, there was no interaction between these factors was found (\(p>0.05\); Table 3). The L* values ranged from 46.98 (B5 product, day 14) to 64.42 (BC product, day 1). The BC product consistently exhibited the lightest color (\(p<0.05\)), regardless of storage time. The addition of 2% chokeberry pomace (B2 product) significantly darkened the burgers. Increasing the chokeberry pomace content to 3.5% and 5% (B3.5 and B5, respectively) further decreased the L* value; however, the differences between the B3.5 and B5 products were not significant. All burger treatments tended to darken during storage, as indicated by a slight decrease (\(p>0.05\)) in the L* value (Table 3). For the a* parameter, a significant effect (\(p<0.05\)) was observed only for burger treatment; neither storage time (\(p>0.05\)) nor the interaction between treatment and storage time (\(p>0.05\)) had an effect (Table 3). The a* value ranged from +5.44 (BC product, day 14) to +9.61 (B5 product, day 14; Table 3). Redness increased with higher chokeberry pomace content. Regardless of storage time, the BC product exhibited lower (\(p<0.05\)) redness than the pomace-containing products (B2-B5). The addition of 2% chokeberry pomace (B2) resulted in a higher a* value than the BC product; however, this difference was significant only on day 1. The B3.5 and B5 products had significantly higher a* values than the BC and B2 products, forming a distinct homogeneous group. For all burger treatments, only minor (\(p>0.05\)) changes in the a* parameter were observed during storage (Table 3). \begin{table}
\begin{tabular}{c c c c c} \hline
**Storage Time [Days]** & **BC*** & **B2*** & **B3.5*** & **B5*** \\ \hline \multicolumn{5}{c}{L* (Lightness)} \\ \hline
1 & 64.42 e 1.85 & 55.95 d 1.77 & 51.02 c 2.85 & 49.73 abc 1.83 \\
7 & 63.13 e 1.87 & 55.23 d 2.46 & 50.23 bc 3.00 & 47 76 ab 2.25 \\
14 & 62.07 e 1.55 & 54.38 d 2.02 & 49.28 abc 2.38 & 46.98 a 2.85 \\ \hline \multicolumn{5}{c}{\(p\)-value} & Treatment: \(p=0.0000\) & Storage time: \(p=0.0001\) & Treatment \(\times\) Storage time: \(p=0.9588\) \\ \hline \multicolumn{5}{c}{+a* (redness)} \\ \hline
1 & +5.77 a 1.17 & +7.30 b 1.05 & +8.99 c 0.97 & +9.44 c 0.77 \\
7 & +5.70 a 0.85 & +6.48 ab 0.55 & +9.00 c 0.60 & +9.59 c 0.47 \\
14 & +5.44 a 1.42 & +6.38 ab 0.61 & +9.27 c 0.94 & +9.61 c 0.76 \\ \hline \multicolumn{5}{c}{\(p\)-value} & Treatment: \(p=0.0000\) & Storage time: \(p=0.4558\) & Treatment \(\times\) Storage time: \(p=0.2024\) \\ \hline \multicolumn{5}{c}{+b*/-b* (yellowness/blueness)} \\ \hline
1 & +8.08 f 0.80 & +4.46 e 0.98 & +0.85 cd 0.52 & +0.44 c 0.65 \\
7 & +10.53 s 0.88 & +3.47 e 0.85 & \(-\)0.74 b 1.40 & \(-\)2.00 a 0.62 \\
14 & +10.58 b 0.57 & +1.87 d 0.45 & \(-\)2.00 a 0.66 & \(-\)2.77 a 0.74 \\ \hline \multicolumn{5}{c}{\(p\)-value} & Treatment: \(p=0.0000\) & Storage time: \(p=0.0005\) & Treatment \(\times\) Storage time: \(p=0.0005\) \\ \hline \end{tabular}  
* Treatments: BC—pork burgers without chokeberry pomace; B2—pork burgers with 2.0% chokeberry pomace; B3.5—pork burgers with 3.5% chokeberry pomace; B5—pork burgers with 5.0% chokeberry pomace; a——mean values regarding a given color parameter marked with different letters are significantly different at \(p<0.05\).  
\end{table} 
Table 3: Changes in color parameters (L*, a*, and b*) (\(n=36\)) in pork burgers with added black chokeberry pomace during storage (mean value \(\pm\) standard deviation). Yellowness (b* parameter) was the color characteristic most affected by chokeberry pomace addition (Table 3). Both treatment and storage time significantly influenced (\(p<0.05\)) the b* value, and an interaction between these factors was also observed (\(p<0.05\)). The b* value ranged from -2.77 (B5 product, day 14) to +10.58 (BC product, day 14). Regardless of storage time, the BC product exhibited the highest b* value. As the level of pomace increased, the b* value gradually decreased.