Simultaneous determination of capsanthin and capsorubin in foods by high-performance liquid chromatography using PDA detector

A high-performance liquid chromatography method with a photodiode array detector (HPLC-PDA) was developed for the simultaneous determination of Capsanthin and Capsorubin in food. These are the two main carotenoids responsible for the red color found in Capsicum annuum and lily (Lilium). Analytes were extracted by ultrasonic vibration method with solvent of acetonitrile (ACN): ethyl acetate containing 0.1% butyl hydroxytoluene (BHT) (1:1, v/v) at a temperature of 40oC for 20 minutes. The sample extract solution was determined by HPLC–PDA with the following conditions: InterSustain C18 column (250 mm x 4.6 mm; 5 µm), mobile phase consisting of a 5 mM ammonium acetate solution, ACN, MeOH, and water following with gradient program, detection wavelength at 450 nm. The method has good specificity, the calibration curve of Capsanthin and Capsorubin has R2 > 0.9997 and the repeatability and recovery meet AOAC requirements. The limit of detection (LOD) and limit of quantification (LOQ) were 0.20 mg/kg and 0.67 mg/kg, respectively. The method was applied to simultaneously determine Capsanthin and Capsorubin in 35 different food products including chili powder, spices, soft drinks, canned products, confectionery, ice cream, and cheese. Capsanthin was detected with a content of 10.5-15.8 mg/kg in chili powder and 3.86-9.78 mg/kg in spices, capsorubin was detected with a content of 2.86-3.92 mg/kg in chili powder and 0.76 -1.64 mg/kg in spices.