## 3 Results and Discussion
### Effect of Organic Acids Addition on the Colour of Red Cabbage Sprouts  
Table 7 shows the color parameters in the CIE L*a*b* and RGB spaces of red cabbage sprouts stored for 14 days, while Figure 4 shows the values of the \(\Delta\)E* color parameter, which indicates the differences between the color of sprouts during storage. Group homogeneity test comparing the effect of the organic acids used on the \(\Delta\)E* values of red cabbage sprouts subjected to 7-day and 14-day storage are shown in Tables 8 and 9, respectively. The greatest changes in color during the 14-day storage of sprouts occurred for the control sample, not fixed (\(\Delta\)E* approximately 8) and for the sample treated with citric acid (\(\Delta\)E* approximately 7), and the smallest for the sprouts treated with peracetic acid (\(\Delta\)E* approximately 3). Similar values of the \(\Delta\)E* parameter were found for sprouts treated with ascorbic acid and lactic acid (\(\Delta\)E* approximately 6), slightly lower values were obtained for the sample treated with acetic acid (\(\Delta\)E* approximately 5). Taking into account the results given in Table 6, it can be seen that the main changes in the color of the sprouts were associated with the development of a darker color with lower intensity of red, yellow, green and blue. Depending on the individual ability of the human eye to judge the differences in color, three different ranges can be distinguished to distinguish between changes in the color value, i.e., \(\Delta\)E* \(<\) 1, imperceptible to the human eye; 1.0 \(<\)\(\Delta\)E* \(<\) 3.3, only noticeable by a specialist, clinically acceptable; \(\Delta\)E* \(>\) 3.3, easy to observe, these color changes are not clinically acceptable. In this study, the values from the last range were obtained for all tested samples, except for sprouts treated with acetic acid. This means that the color changes were noticeable, and the samples differed significantly. For acetic acid-treated sprouts, the color change was only noticeable by a skilled person, clinically acceptable (\(\Delta\)E* \(<\) 3.3). Color changes of sprouts that occurred during storage may result from changes in the content of anthocyanins, the main color-imparting compounds, present in significant amounts in red cabbage and sprouts [66]. In research by [PERSON] et al., (2016) on changes during storage of elderberry juice concentrate solutions, pigment content decreased in each tested sample as the effect of temperature and pH. In that study, the lowest changes in color parameters were noticed at the lowest tested pH of 3, which proved the high stability of anthocyanin dyes in this pH range. At the highest tested pH, 5, the elderberry juice concentrate was darker, which was related to the brownish-red shade of the tested samples. It resulted, inter alia, from the accumulation of anthocyanin degradation products. In this study, the greatest color changes during storage were obtained in samples not treated with individual acids (the highest value of \(\Delta\)E*). Taking into account the obtained values of the individual color components, it can be seen that after 14 days of storage, the sprouts not treated with organic acids were significantly darkest in color, compared to all samples treated with solutions of individual acids, which is not noticed immediately after treating the sprouts with acids and after 7 days of storage (in these cases, only some of the sprouts were lighter in color compared to the control sprouts). In this study, as well as in [PERSON] et al., (2016) [62], the values of the color parameters changed during the storage of the tested samples. In the cited work, the brightness of the tested samples increased with the increasing of pH, storage time and temperature, while the values of the a* (red color) and C* (color saturation) color parameters decreased. The b* parameter values (share of yellow color) decreased with increasing pH during storage. Similar relationships for the color parameters a* and b*, regardless of the pH, were also obtained in this study.