## 3 Results and Discussion
Green light was not chosen to process the experiment because it was documented in studies that a green monochromatic light source did not affect sprout development. Only slight enrichment of the spectrum with other light wavelengths was contemplated to improve photomorphogenesis [39; 42]. Figure 1: Mass of red clover sprouts during 7 days of sprout growth depending on irradiation and pulsed electric field (PEF) treatment prior to sowing. Values are presented as mean \(\pm\) SD (\(n=3\)). In this study, it was observed that the content of carotenoids depends on the conditions of the used light (Figure 2). The dominant carotenoid in germinating red clover seeds is lutein, the content of which varies from 743 mg/kg in sprouts grown in red light, to 862 mg/kg in sprouts grown in UVA, and 888 mg/kg in sprouts grown in blue light. Lutein is a carotenoid with widely documented health-promoting properties. Obtaining new sources of lutein is desirable. At the same time, it was observed that the use of UVA or blue light during cultivation had a positive effect on the formation of other carotenoids, including \(\beta\)-carotene and zeaxanthin. UVA and blue light are the most preferred for obtaining carotenoid dyes. Under these cultivation conditions, the highest content of the total value of tested carotenoids (\(\beta\)-carotene, lutein and zeaxanthin) in red clover sprouts was obtained, respectively 1750 mg/kg (kg of dry weight) in the case of UVA irradiation and 1892 mg/kg using blue irradiation. Comparing these results to sprouts grown in white light, the increase in the content of these dyes in sprouts irradiated with blue light is statistically significant and equal to 42% in \(\beta\)-carotene, 19% in lutein and 14% in zeaxanthin (Figure 2, Tables 3-5). The content of lutein in sprouts from crops cultivated under red light was slightly lower than under white light, but the difference is not statistically significant (Table 4). Carotenoid content was studied in mature red clover plants for fodder grown in the field. Research shows that the main carotenoid is lutein, its content was 136 mg/kg DM (dry matter), and the total \(\beta\)-carotene content was 29 mg/kg DM [43]. In other studies, the composition of the carotenoids in red clover is different, and the content of lutein, \(\beta\)-carotene and zeaxanthin is much higher, respectively 237.7, 100.3 and 91.7 mg/kg DM. It should be noted that in recent studies, clover after harvesting has been subjected to a consolidation process [44]. Other authors report that the content of \(\beta\)-carotene in red clover is about 200 mg/kg DM, and the content of this carotenoid in _Trifolium repens_ varies from 300 to 730 mg/kg DM depending on the harvesting place [45]. In the experiment where the subject was Alsike clover, also belonging to the genus _Trifolium_, the content of lutein and \(\beta\)-carotene was much higher and equalled 208.9-243 mg/kg and 35.4-123.4 mg/kg fresh weight, respectively [46]. The effect of various types of LED lighting on the content of carotenoids in alfalfa sprouts (also belonging to _Fabaceae_ family) was investigated [47]. The combination of the red and blue LEDs used during cultivation increased lutein content from 82.6 to 108.2, and \(\beta\)-carotene from 26.6 to 44.6 mg/kg fresh mass of sprouts [47]. However, the research did not cover the whole sprout, only cotyledon. Increasing the intensity of blue light during the cultivation of betroot (_Beta vulgaris_ L.) and parsley (_Petroselinum crispum_ Mill.) caused an increase in the content of carotenoids as compared to irradiation with red light. It has been shown that increasing the proportion of blue light intensity in these microgreens results in an increase in lutein content from 103.8 to 118.5 mg/kg of fresh beet mass, from 122.9 to 190.7 mg/kg of fresh parsley, and \(\beta\)-carotene, respectively from 0.09 to 0.87 and 0.54 to 0.86 mg/kg, and zeaxanthin from 1.39 to 3.20 and up to 0.84-14.4 mg/kg, respectively [35].