# Effect of Plant Extracts Addition on the Physico-Chemical and Sensory Properties of Biscuits
## 3 Results
### Color Attributes  
Color is one of the key factors affecting the initial consumer acceptability of the food product. Nowadays, consumers are aiming for a healthy diet which includes natural dye compounds in foods instead of artificial ones. In this sense, the enrichment of biscuits with plant extracts that contain natural dyes such as anthocyanins could potentially have a positive influence on consumers' choice priorities. Color attributes of biscuits enriched with different concentrations of cranberry and blueberry extracts are presented in Table 3. Lightness values (\(L^{*}\)) were significantly decreased with increasing the blueberry powder from 0 to 6% in biscuits (\(p<0.05\)). However, no significant differences were observed in lightness values between 6 and 9% blueberry-enriched biscuits (\(p>0.05\)). A similar decreasing trend on lightness values was observed with increasing the cranberry powder from 0 to 9% in enriched biscuit samples. Lower lightness in enriched biscuits can be explained by the dark color derived from natural dye compounds of berries such as anthocyanins and by Maillard reactions during baking [17]. Similarly, [PERSON] et al. [17] reported that enriched biscuits with approximately 5% blueberry powder provided lower lightness compared to the control samples. [PERSON] et al. [29] also reported that the addition of 10% raspberry, red currant, and strawberry pomace significantly decreased the lightness of the enriched cookies. On the other hand, redness values (\(a^{*}\)) were significantly increased with increasing the blueberry plant extract addition from 0 to 9% in biscuit composition. Similarly, redness values of the biscuits were increased with increasing cranberry powder addition from 0 to 3% and from 3 to 9% (\(p<0.05\)). The increase in redness value in enriched biscuits can be attributed to high anthocyanin content known as red pigment present in berries [30]. [PERSON] et al. [31] reported a strong significant correlation between redness and anthocyanin content in anthocyanin-enriched biscuits. A previous study also reported that redness values were increased with increasing the blueberry content in biscuits [17]. Yellowness (\(b^{*}\)) values of biscuits were significantly reduced after 3% of cranberry powder addition (\(p<0.05\)). Meanwhile, no significant change on yellownness was observed between 3, 6, and 9% cranberry-enriched biscuits (\(p>0.05\)). On contrary, yellownness values of the biscuits were significantly reduced after 3% and after 6% blueberry powder addition (\(p<0.05\)). The yellownness decrease in enriched biscuit samples can be explained by the lower amount of wheat flour in biscuit formulation (Table 1), and consequently lower carotenoid content, compared to control biscuit samples [31]. [PERSON] et al. [29] also reported that cookies enriched with addition of 10 to 20% raspberry, red currant, or strawberry pomace had significantly lower yellownness values compared to control samples. Chroma or saturation values (\(C^{*}\) value) of control samples (without plant extract) were significantly higher than both blueberry- and cranberry-enriched biscuits (\(p<0.05\)). Similarly, [PERSON] et al. [32] reported that chroma values of biscuits were significantly reduced with addition of either black currant or jostaberry powders. The \(h\)-value of the biscuits was significantly decreased with increasing the concentration of blueberry powder from 0 to 9% (\(p<0.05\)). Similarly, the \(h\) value of cranberry-enriched biscuits decreased with increasing the powder concentration from 0 to 3 % and from 6 to 9 % (\(p<0.05\)). Previousauthors reported similar results of the _h_-value decreasing with the addition of plant extract powder in biscuits (17; 32). Blueberry-enriched biscuits (3 to 9%) had significantly lower lightness, yellowness, and chroma values compared to cranberry-enriched biscuits (\(p<0.001\)). Similarly, blueberry-enriched biscuits (3 to 9%) had significantly lower redness values compared to cranberry-enriched biscuits.