Supercritical Co2 Extraction of Carotenoids from Carrots and Evaluation of Products

Carotenoids are gaining growing interest in food industries due to their nutritional and colorant properties. The objectives of this study were to extract carotenoids from carrots with supercritical CO2 (SC-CO2) and to evaluate the antioxidant activity of the crude carrot oil extract and color of the carrot residue. Crude carrot oil was extracted from freeze-dried carrots with SC-CO2 at different temperature (40, 55, and 70 °C) and pressure (27.6, 41.3, and 55.1 MPa) conditions for 4 h. Carotenoids in the crude carrot oil were identified and quantified by HPLC analysis. The antioxidant activity of the crude oil was determined using the ferric thiocyanate method. The color parameters (‘L’, ‘a’, and ‘b’) of the carrot residue were determined by HunterLab spectrocolorimeter. Hue, chroma, and the overall color change ∆E between feed material and residue were calculated. The main carotenoids in the crude carrot oil extract were α-carotene, β-carotene, and lutein. The extraction yield of α-carotene was 137.8-330.3 μg/g feed material, β-carotene was 171.7-386.6 μg/g, lutein was 23.5-37.5 μg/g, and total carotenoids was 339.3-745.5 μg/g. The antioxidant activity of the SC-CO2 extracted carrot crude oil ranged from 24.98 to 43.14, which was approximately half of that of butylated hydroxytoluene BHT (75.04) measured at equal concentrations of crude oil and BHT, which is a commonly used synthetic antioxidant. The intensities of redness ‘a’ and yellowness ‘b’ of the carrot particles decreased and the brightness ‘L’ increased after extraction. Supercritical CO2 extraction is an efficient technique to obtain natural food colorant with high antioxidant activity.