# Use of Bilberry and Blackcurrant Pomace Powders as Functional Ingredients in Cookies
## 3 Results and Discussion
### Color Parameters, Titractable Aidity and pH  
Color is one of the most important parameters in terms of visual quality evaluation and consumer acceptance. Effects of the incorporation of BIPP and BCPP on the color parameters of cookies are given in Tables 4 and 5, respectively. The partial replacement of the wheat flour both with BIPP and BCPP significantly changed color. Both BIPP and BCPP darkened the color of cookies considering that the L* values significantly (\(p<0.05\)) decreased as the substitution level increased. The decrease rate of L* values was higher for BIPP than for BCPP due to the dark purple color of BIPP (Figure 1). A similar evolution of L* values has previously been reported in cookies supplemented with carrot [68], apple [3], pineapple, pear [11], or melon by-products [14]. A regular decrease in b* values with respect to the control was also recorded upon increasing the addition level of BIPP and BCPP, with a higher rate of the decrease for BIPP as compared with BCPP. Similarly, yellowness (b* values) decreased significantly in biscuits as compared to the control when apple pear powder [70] or pear pomace [11] were added at levels above 15%, but then increased in cookies fortified with apple by-products [3]. At a 10% BIPP replacement level, an intense dark but attractive purple color was imparted to the cookies. [PERSON] et al. [8] also reported that the addition of blueberry pomace in cookie formulation led to the decrease in b* values and attributed this evolution to the presence of blue anthocyanins. The addition of BCPP also exerted a positive influence on the color of cookies as the a* values increased progressively with the increasing addition levels, indicating a change in the color chromaticity towards red. At 5% and 10% BCPP substitution levels, the cookies turned a golden-brown color with a pink tint in the central section. Figure 1 presents the appearance of the BIPP, BCPP, control, \begin{table}
\begin{tabular}{c c c c c} \hline  & **CC** & **CBI2.5** & **CBI5.0** & **CBI10.0** \\ \hline L* & 58.70 \(\pm\) 0.66 a & 31.35 \(\pm\) 0.92 b & 23.37 \(\pm\) 1.23 c & 19.49 \(\pm\) 0.66 d \\ \hline a* & 7.65 \(\pm\) 0.44 ab & 7.97 \(\pm\) 0.19 a & 7.32 \(\pm\) 0.35 c & 3.06 \(\pm\) 0.44 d \\ \hline b* & 20.41 \(\pm\) 0.79 a & 8.47 \(\pm\) 0.55 b & 3.48 \(\pm\) 0.47 c & 2.60 \(\pm\) 0.22 d \\ \hline C* & 21.79 \(\pm\) 0.89 a & 9.02 \(\pm\) 0.46 b & 8.71 \(\pm\) 0.22 b & 7.77 \(\pm\) 0.76 c \\ \hline h* & 69.46 \(\pm\) 0.41 a & 23.55 \(\pm\) 3.02 b & 19.94 \(\pm\) 3.42 c & 19.77 \(\pm\) 3.27 c \\ \hline \(\Delta\)E & - & 32.17 \(\pm\) 1.63 c & 39.58 \(\pm\) 1.49 b & 42.89 \(\pm\) 1.21 a \\ \hline Weight (g) & 11.95 \(\pm\) 0.45 c & 13.65 \(\pm\) 0.69 b & 14.63 \(\pm\) 0.45 a & 14.37 \(\pm\) 0.78 a \\ \hline Diameter (mm) & 49.07 \(\pm\) 1.28 b & 51.12 \(\pm\) 0.77 a & 51.14 \(\pm\) 0.94 a & 51.63 \(\pm\) 0.76 a \\ \hline Thickness (mm) & 8.48 \(\pm\) 0.29 c & 8.97 \(\pm\) 0.43 b & 9.44 \(\pm\) 0.28 a & 9.29 \(\pm\) 0.46 ab \\ \hline Spread ratio & 5.79 \(\pm\) 0.15 a & 5.71 \(\pm\) 0.28 a & 5.42 \(\pm\) 0.23 b & 5.57 \(\pm\) 0.30 ab \\ \hline Titractable acidity (\%, as citric acid) & 0.04 \(\pm\) 0.01 d & 0.06 \(\pm\) 0.01 c & 0.09 \(\pm\) 0.01 b & 0.13 \(\pm\) 0.01 a \\ \hline pH & 6.40 \(\pm\) 0.08 a & 6.20 \(\pm\) 0.11 b & 6.04 \(\pm\) 0.06 b & 4.99 \(\pm\) 0.09 c \\ \hline \end{tabular} Different lowercase letters indicate significant differences between cookie formulations (\(p<0.05\)); CC—control cookie; CBI2.5, CBI5.0, and CBI10.0—cookies with 2.5%, 5%, and 10% of the wheat flour replaced by BIPP, respectively.  
\end{table} 
Table 4: Effect of bilberry pomace powder addition on the color, physical parameters, titractable acidity, and pH of the cookies. and supplemented cookies, both at the surface and in the central section. A similar trend of increased redness (a* values) was previously recorded in cookies supplemented with apple [3; 18; 19] or pear pomace [11]. Lower L* values and higher a* values on the surface of cookies were also observed by [PERSON] et al.