A simple spectrophotometric method for the estimation of α-carotene, β-carotene and lycopene concentrations in carrot acetone extracts

Abstract

We developed a simple and effective method for measuring concentrations of α-carotene, β-carotene and lycopene in acetone extracts of common carrots and Kintoki red carrots. This method utilizes the differences in visible absorption spectra for each of these pigments. Concentrations of each pigment can be determined by measuring the absorbance at 443, 475, 492 and 505 nm, i.e., A443, A475, A492 and A505, respectively, and performing calculations, The equations, with correlation coefficients between prediction and measurement (r), and the standard errors of prediction (SEP), are as follows : α-carotene (mg/L) = 0.847 A 443 + 3.218A475-1.499A492-3.519A 505-0.119(r=0.965, SEP = 0.231) ; β-carotene (mg/L)= - 1.488A443+ 4.844A192-2.352 A505- 0.098 (r=0.946, SEP = 0.228) ; lycopene (mg/L) = 0.256 A443-1.984A 492+ 5.088A505-0.237 (r=0.996, SEP = 0.139). A standard spectrophotometer is sufficient for this method, and concentration calculations can be made within minutes of taking the absorbance measurements.