Carotenoids have been extracted from rosehip fruit using supercritical CO2 at various extraction conditions. Carotenoids content in the extract was also determined by high-performance liquid chromatography (HPLC) method. Extraction was carried out at pressures of 150-450 bar, temperatures of 40-80 °C and CO2 flow rates of 2-4 ml/min. A full 33 factorial design, in which pressure, temperature and CO2 flow rate were used as design factors, coupled with statistical analysis of the results, by using analysis of variance (ANOVA), was used to optimize operating condition of carotenoids extraction in SC-CO2. Extraction rate constant was calculated from the dependence of extraction yield on extraction time at 10, 20, 30, 50, 80, 110 and 150 min. Based on the experimental results, the total carotenoids extracted from rosehip fruit were found to be 10.35-20.88 mg/g fruit, and the maximum amount of carotenoids extracted was obtained at 80 °C, 450 bar and 4 ml/min. As determined by HPLC methods, the carotenoids extracted contained lycopene and β-carotene as main components, and small amount of lutein. The amount of lycopene, β-carotene and lutein extracted were 1.180-14.37 mg/g feed, 0.154-1.017 mg/g feed and 1.258-16.84 μg/g feed, respectively. The optimization results demonstrated that temperature was to be the influential variable on the extraction yield of carotenoids, with the statistical significant effect p-value was smaller than 0.05. For lycopene extracted, all variables (temperature, pressure and CO2 flow rate) were to be the influential variables, but there is no possible interaction among variables. For β-carotene and lutein extracted, the influential variables were pressure and CO2 flow rate without any interactions among variables. The mean extraction rate constant, k, of total carotenoids increased with increasing pressure and temperature, and the k values were (3.344-5.851) × 10-3 min-1.
- Extraction rate constant
- Supercritical CO extraction