## 3 Results and Discussion
The analysis of the total color difference between the snacks produced with common flaxseed pomace (8.31) and those with golden flaxseed pomace (3.98) showed that their \(\Delta\)E differed significantly compared to the control snacks. The difference between these values was 4.33 and hence fitted within the range of 3.5 \(<\)\(\Delta\)E \(<\) 5, which means that the color of the snacks produced from both varieties of flaxseed is perceived by the observer as significantly different [6]. This difference is also reflected in the previously described reduction in brightness (L) caused by hue angle shift toward red color. This effect is caused by Maillard reactions occurring during the extrusion process. Many authors have pointed to fiber content as a feature that can also cause a significant change in the color of extruded products. The higher fiber content increases viscosity of the extruded material and contributes to higher friction forces, which consequently leads to an increase in temperature of the extruded mass and intensification of Maillard reactions, caramelization reactions, or pigment degradation processes [20]. Also, the proportions of flaxseed pomace in the snack formula had a significant impact on the objective difference in the colors of the snacks, with each increase in the pomace proportion in the extruded mixture resulting in an increase in the \(\Delta\)E value. The snacks produced with 5% pomace content differed from the snacks made without pomace by only \(\Delta\)E = 2.45. However, in the snacks with a 10% addition of pomace, this difference was \(\Delta\)E = 7.91; i.e., it was higher than the expected value (resulting from the doubling of the flaxseed pomace addition) by 3.01, i.e., by 61%. In the case of snacks with the highest analyzed pomace addition (15%), the value of \(\Delta\)E = 14.22 was higher than the expected value (resulting from the tripling of the flaxseed pomace addition) by 6.87, namely by as much as 93%. The described increase in the total color difference clearly indicates that it is not only due to the increase in the content of dark pomace in the material but also due to the synergistic action of other factors, including the caramelization and Maillard reactions. It should also be noted that only in the case of the snacks with the lowest addition of flaxseed pomace was the total color difference less than 5. In the case of the snacks with 10% and 15% addition of flaxseed pomace, the \(\Delta\)E value significantly exceeded the threshold value of 5, after which the observer assesses the samples as having a completely different color [6,25]. Also, the use of cocoa in the snack formula had a significant impact on the objective difference in the color of the snacks. It was found to increase the \(\Delta\)E value (6.76) compared to the snacks produced without cocoa (5.53). Technological operations (such as cooking, baking, drying, roasting, extrusion, etc. ), in which cocoa is exposed to high temperatures, are crucial in imparting desired organoleptic attributes to food products, including color. As a result of the high temperatures applied, these processes result not only in the degradation of enzymes and polyphenic and flavonoid pigments but also trigger Maillard reactions, whose products are the major players in ensuring the right quality of cocoa [29,30]. Ana lyzing the effect of pH on the color of extruded products, it was observed that products with a darker color were obtained in an alkaline environment because the degradation of polyphenols occurred to a lesser extent. There are also reports that the fermentation process of cocoa beans can stabilize the amounts of polyphenols and tannins when subjected to various high-temperature culinary treatments [19].