# The Impact of Effective Microorganisms on Flesh Color and Chemical Composition of Raw Potato Tubers
## 4 Discussion
Thus, each color can be assessed by the L*, a*, b* coordinates (the color here is a point in the space built by the three axes) [6; 7; 56]. To produce, for example, chips of the same color, a standard (standard) is established and the current production (samples) is compared with it. Thanks to the development of the CIELab system, the difference between the color of the standard and the color of the sample can be calculated from the distance between these two points and recorded as a numerical value. In industry, this difference is marked as \(\Delta\)E * [57]. Usually, the total color deviation \(\Delta\)E * is not sufficiently indicative of color consistency, and it is worthwhile to establish additional criteria for the color control to be fully valid and reliable. The amount of flesh color saturation in the conducted studies was found to be related to its brightness, which was also confirmed by the research of other authors [5; 27; 50; 51]. [PERSON] et al. [8] showed a highly significant correlation between subjective methods of assessing the darkening of raw tuber flesh and the parameters of the CIELab system and the a */b * coefficient. Visible light is only a small fraction of the electromagnetic field; the spectrum with the spectral range from 390 nm (violet) to 750 nm (red), according to [PERSON] [7], changes even in this narrow visible range the sensitivity of the human eye to color. In the conditions of artificial lighting, in the moderate to strong range, the human eye, according to [PERSON] [5], is more sensitive to yellow-green light (around 550 nm). In the opinion of [PERSON] [56], color is an impression caused in our brain by electromagnetic radiation in the range of 380-780 nm and affecting the human eye. This author claims that all colors can be divided into achromatic and chromatic colors. The former covers the colors from white through neutral gray to black; they only have one color attribute: luminosity for secondary light sources and luminosity for primary sources. The other colors are chromatic with up to three attributes. Their identification, however, requires greater knowledge of the principles of physics [5; 27; 57]. We divide colors into chromatic and achromatic, which are characterized by high brightness [57]. In the CIELab system, they are assumed to be the main, vertical ones in solids of colors. A mixture of white light in combination with a monochromatic color produces a chromatic color. In this trial, a mixture of white and monochromatic light was used to determine the brightness of the tested samples and their color saturation. The results obtained in this research showed that using effective microorganisms (EMs) in potato cultivation significantly increased the dry matter and starch content, and at the same time reduced the content of total sugars, reducing sugars, and sucrose in potato tubers, compared to the standard practice where fungicides were applied three times. However, the management of cultivation practices did not affect the vitamin C component of the tuber's fresh weight. Opinions on this subject are divided. [PERSON] et al. [4], by examining the effect of biological preparations BP500 and BP501 on potato cultivars, proved that the BP 501 preparation, and the combination of BP 500 and BP 501 preparations, significantly increased the starch content in potato tubers. [PERSON] [48], while assessing the influence of two other microbiological preparations (EM Farma Plus and UGmax), did not find any influence on the starch content of the tubers. [PERSON] and [PERSON] [62], examining the effect of the EM-Farming microbiological preparation on eight potato cultivars, proved these preparations significantly increased the content of nitrogen, copper, iron, and boron in tubers but did not cause changes in the content of phosphorus, potassium, magnesium, calcium, manganese, and zinc.