Extraction of beta carotene

Extraction of beta carotene - Extraction and Quantitative...

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Extraction and Quantitative Determination of β-Carotene Introduction β-carotene is a lipid found in many fruits and vegetables. It is most commonly found in root vegetables that are orange, such as carrots and yams, as well as green leafy vegetables such as spinach. It is a hydrocarbon with many conjugated double bonds (figure 1), which give it a strong color. Due to resonance delocalization, there are small energy differences between molecular orbitals in β-carotene. Since it absorbs mostly at wavelengths of about 449 nm, it absorbs mostly at the blue region of visible spectrum, and transmits at the red-orange region, which is what gives it its red-orange color. . In this experiment, β-Carotene will be extracted from carrots using liquid-liquid extraction. Once the carotene has been extracted, a serial dilution of known concentration of β-carotene will be used to construct a standard absorbance curve and determine the extinction coefficient based on Beer’s Law. Then, the standard curve will be used to determine the solute concentration in an experimental sample. After that, the purity of the experimental β-carotene sample will be analyzed by thin-layer chromatography, and total amount of β-carotene extracted will be determined, and its approximate percentage (by mass) in carrots will be calculated. Procedure Carrots were shredded and placed in a round-bottom flask, and 95% ethanol was added to the flask. A reflux condenser was set up with heat, and the mixture was gently refluxed for 30 minutes. Then, it was allowed to cool down. The ethanol extract was then poured
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Extraction of beta carotene - Extraction and Quantitative...

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