Carotenoids are the most widespread pigments in nature [1] that have been interesting for research in many scientific areas for centuries and are still intensively researched. These are the compounds that are present in yellow, orange and red plants, unsaturated hydrocarbons that are derived from isoprene units and consist entirely of carbon and hydrogen (carotenes) or carbon, hydrogen and oxygen (xanthophylls). Fruits and vegetables that contain vitamin C, vitamin E, tocopherol, and carotenoids are suggested as natural sources of antioxidants [2] . Antioxidants are molecules that can prevent various diseases and are believed to slow down aging process. Carrot (Daucus carota L.) is a biennial herb that belongs to the Apiaceae family. Carrot root contains 88% water, 1% protein, 7% carbohydrates, 0.2% fat and 3% fibre, along with vitamins (antioxidants) and minerals [3] . Tetraterpenoid pigments (C₄₀) carotenoids appear in several isomeric forms, of which α and β-carotene are two primary forms of carotene. Among carotenoids, β-carotene is the substance most often found in food supplements [4] . The β-carotene molecule found in carrots, pumpkins, apricots, plums, tomatoes, asparagus and other plants is a precursor of vitamin A. In Latin, the word “carotene” means carrot and that is the origin of the name carotene itself. The biggest source of beta-carotene is precisely from carrots. In the human body, β-carotene is broken down by β-carotene dioxygenase in the mucosa of the small intestine into two molecules of retinyl, which is later reduced to vitamin A (retinol) [5] . Beta-carotene is considered the main carotenoid that also has antioxidant properties [6] [7] and therefore reduces the risk of many diseases [8] [9] (cancer, cardiovascular diseases and old age-related diseases). The structure of beta-carotene was derived in 1930 [10] and is shown in Figure 1 . The molecular formula of beta-carotene is C₄₀H₅₆ and the molar mass is 536.9 g/mol. The carotenoid molecule (β-carotene) is present in the form of red to red-brown crystals with a melting point of 176˚C - 184˚C [11] . Beta-carotene is practically insoluble in water and hardly soluble even in methanol, acetonitrile (ACN) or dimethylsulfoxide (DMSO). Solubility was improved in hexane, chloroform, methylene chloride and tetrahydrofuran (THF) as the best solvent tested [12] - [14] .

The IUPAC name of beta-carotene is 1,3,3-Trimethyl-2-[3,7,12,16-tetrametil-18-(2,6,6-trimethylciclohex1en1il)-octadeca-1,3,5,7,9,11,13,15,17-nonaen-1-il]ciclohex-1-ene.

Beta-carotene is very important primarily because of its action, the potential of provitamin A and as a compound used as a dye. The purpose of the research is the isolation of the selected carotenoid utilizing the extraction method, which has shown good results. Therefore, the aim of the research is to isolate and identify beta-carotene.

Beta-carotene, an isoprenoid, is hydrophobic in nature and as such is soluble in organic solvents. Usually, non-polar solvents, such as hexane, petroleum ether or tetrahydrofuran (THF), are an excellent choice for extraction of non-polar carotenes or esterified xanthophylls, whereas polar solvents such as acetone, ethanol, and ethyl acetate are more appropriate for extraction of polar carotenoids [15] . In this research, organic solvents such as methanol, methylene chloride, hexane, acetone and isopropanol were used. During the extraction of beta-carotene from carrots, methanol as a solvent in which beta-carotene is not soluble separates polar organic substances. Methylene chloride as the second solvent in this research extracts non-polar organic substances. After solvent extraction, the obtained carotenoid was analysed. Figure 2 shows the FTIR spectra of standard and isolated β-carotene, obtained in the range from 450 to 4000 cm⁻¹. The spectrum of the isolated carotenoid shows the presence of CH₃ stretching at 2921.12 cm⁻¹ and 2850.72 cm⁻¹. Wavelengths at 755.37 cm⁻¹ and 696.46 cm⁻¹ of fingerprints indicate the presence of an aromatic alkene. The region at the wavelength of 1452.37 cm⁻¹ indicates vibrations of antisymmetric deformation of CH₃ and CH₂ groups [16] . The spectrum of the isolated compound has a characteristic peak at 1092.63 cm⁻¹ corresponding to C-O stretching vibrations (1). Comparing with the spectrum of the β-carotene standard, we can say that the isolation of the chosen carotenoid has been confirmed (2).

Analysis of the UV/Vis spectrum of isolated beta-carotene is shown in Figure 3 . The spectrum shows the wavelengths at Λmax = 247.97 nm and Λmax = 450 nm and comparing it with the spectrum of the standard carotenoid (1) confirms that the isolated molecule has been identified (2).

Figure 4 shows the TLC chromatography of the isolated beta-carotene compound compared to the beta-carotene standard. The Rf values of the isolated carotenoid are 0.90 compared to the standard, which is 0.91. With this analysis, we can see that beta-carotene was successfully isolated with the appropriate mobile phase hexane:acetone (9:1) and it is confirmed by the literature data of other studies [17] .

By HPLC analysis, the isolated beta-carotene was confirmed with an absorption maximum of 448 nm compared to the β-carotene standard of 450 nm ( Figure 5 ). Small impurities are present in the sample compared to the standard. In this study, the retention time of β–carotene was 3.8 min with the mobile phase of hexane:isopropanol (9:1).

Carotenoids are classified as a group of micronutrients that have significant antioxidant, anticancer and anti-inflammatory properties. Some of these carotenoids are converted by the body into vitamin A, which is necessary for eyesight, growth and proper development. This is precisely why the beta-carotene molecule is important because it acts as provitamin A.

The growing demand for beta-carotene, i.e. natural beta-carotene, has led to research and consideration of extraction methods from natural sources. Beta-carotene is widely used in the food, pharmaceutical and cosmetic industries. In this research, a selected organic compound (carotenoid) was identified from carrots. The selected reflux method for beta-carotene extraction showed good results. The results of FTIR, UV and TLC analysis indicate a successfully isolated molecule. HPLC analysis also confirms the isolated carotenoid, which is compared with standard beta-carotene.