An HPLC Method for the Analysis of Orange Color in Food Using β-Cryptoxanthin as an Indicator

摘要

An HPLC method for the analysis of orange color in food using β-cryptoxanthin as an indicator was established. Orange color was extracted from food samples with ether, and after evaporation of the extract, the residue was dissolved in methanol, to which 5% sodium hydroxide–methanol was then added. The mixture was occasionally stirred, then allowed to stand for 24 hr at room temperature, in a tightly sealed container shielded from light. Subsequently, distilled water was added and the pH of the mixture was adjusted to be below 4.5 using hydrochloric acid. It was then purified with a C18 cartridge before being subjected to HPLC analysis. The HPLC conditions were as follows: column, Tosoh TSK gel ODS-80Ts (5 μm, 4.6 × 150 mm); column temperature, 45°C; mobile phase, acetone–water (61); flow rate, 1.2 mL/min; detection wavelength, 460 nm. The average recoveries of the orange color were over 73.9% from juice and jelly fortified at the concentrations of 2–100 μg/g. The coefficients of variation were 10.7% or less. Twenty-two commercially available foods such as juice, candy, jelly, sherbet, and cake that had a label stating the use of orange color were analyzed, and the detected β-cryptoxanthin concentrations ranges from 0.011 to 0.275 μg/g.