Simultaneous determination of crocin and crocetin in food samples by highperformance liquid chromatography (HPLC-PDA)

Abstract

Crocin and crocetin are two bioactive compounds found in saffron and gardenia. In the food industry, due to their natural yellow or orange color, they are used as food colouring. The study was carried out to optimize the high-performance liquid chromatography combined with a photodiode detector (HPLC-PDA) to simultaneously determine the crocin and crocetin content in food. Analytical samples were ultrasonicated with ACN:H2O (1:1, v/v) solvent for 30 minutes. The sample solution was determined by HPLC – PDA with the following conditions: Sunfire C18 column (250 mm x 4.6 mm; 5 µm) mobile phase consisting of 0.1% formic acid and ACN using gradient program. The method has good specificity, the standard curves of crocin and crocetin have correlation coefficients R2 > 0.999, respectively, repeatability and recovery meet AOAC requirements. The limit of detection (LOD) for  crocin and crocetin were 0.5 mg/kg and 0.25 mg/kg, respectively. The method has been applied to simultaneously determine crocin and crocetin in 15 real samples and results in 13 out of 15 samples detecting crocin content, 11 out of 15 samples detecting crocetin content, and in 2 out out of 15 samples. neither crocin nor crocetin was detected. The gardenia powder group contained the highest content of crocin and crocetin (23.5 g/100g – 24.4 g/100g) and dried lychee samples - sun-dried or dried gardenia contains the second highest concentrations of crocin and crocetin in the food group.