[Optimization and application of determination method of cholesterol in various dishes]

To establish a rapid and accurate method for the determination of cholesterol in a variety of finished dishes.

The samples were saponified with ethanol and potassium hydroxide solution at 80 ℃ for 0.5 h, then vortexed and mixed fully with ultrapure water, and extracted twice with 25 mL n-hexane. The extracting solution were evaporated to dryness under vacuum and redissolved by ethanol, finally determined by gas chromatograph. The sample loading solution was separated by HP-5 capillary column(30 m×0.25 mm, 0.25 μm) and quantified with external standard method.

The method had good linearity in the concentration range of 2.5-250 μg/mL for cholesterol and the correlation coefficient was 0.9999. The detection limit was 0.25 mg/100 g edible part, and the limit of quantification was 0.75 mg/100 g edible part. Three representative samples were picked for spiked recovery experiments with three concentration levels according to their content of cholesterol. The average recovery rates ranged from 91.1% to 101%, and the relative standard deviations were not more than 5%. The content range of cholesterol in 15 vegan dishes was from negative to 10.3 mg/100 g edible part, in 14 dishes contained meat and vegetable was from 2.34 to 80.2 mg/100 g edible part and in 9 pure meat dishes was from 25.4 to 288 mg/100 g edible part.

Compared with the national standard method, the method is simple to operate and more friendly to the experimenter while ensuring the accuracy and sensitivity requirements. It can meet the needs of efficient batch determination of cholesterol in a variety of finished dishes.