NGHIÊN CỨU ĐỊNH LƯỢNG ĐỒNG THỜI MỘT SỐ CAROTENOID TRONG NƯỚC CAM TỰ NHIÊN

Tóm tắt

The reverse phase - high performance liquid chromatography (RP-HPLC) method was developed to
simultaneously determine three carotenoids, including lutein, lycopene, and β-carotene, in orange juice.
Orange juice was extracted with n-hexane for 10 minutes, centrifuged for 5 minutes at 6000 rpm, and then
evaporated under vacuum. A volume of 5 mL of the mobile phase was added, filtered through filter paper,
and injected into the HPLC-PDA system under the following conditions: XBridge® C18 column (250 mm x
4.6 mm, 5 µm), mobile phase consisting of a mixture of acetonitrile: methanol: water: ethyl acetat =
70:9.6:0.4:20 (v/v/v/v) according to an isocratic program, detection wavelength 455 nm. The calibration
curves for lutein, lycopene, and β-carotene determination had R² coefficients > 0.9997, and the validation
parameters met AOAC standards. The method detection limits for lutein, lycopene, and β-carotene were
0.002 mg/L, 0.003 mg/L, and 0.006 mg/L, respectively. The validated method was applied to simultaneously
determine lutein, lycopene, and β-carotene in 45 Vietnamese orange juice samples. Lycopene was not
detected in the Vietnamese orange samples. The content of lutein and β-carotene varied depending on the
orange variety and region. The β-carotene content in Citrus nobilis was much higher than in the other
orange varieties in this study. The minimum and maximum contents of lutein in the collected samples were
0.018±0.008 mg/L and 0.221±0.039 mg/L, respectively, whereas these values for β-carotene content were
0.020±0.009 mg/L and 0.423±0.099 mg/L, respectively.