Determination Of Folates In Leafy Vegetables By High-performance Liquid Chromatography(HPLC) And The Effect Of Different Processes On Folates Retention

Folic acid is the necessary material to human in the use of sugar and amino acids and the body cell growth, its role in human health is increasingly being recognized. This article take the common leafy vegetables spinach, lettuce, cabbage and so on as experimental materials,studies high-performance liquid chromatography(HPLC) determination folic acid condition as well as the effect of different processing on folates retention, draws the following conclusions:(1) In the experiment, through optimizing conditions such as liquid phase conditions,column temperature, wavelength and other conditions, we had got the conditions to examine5-methytetrahydrofolate and folic acid by HPLC. The flow rate was 0.4 ml/min; the injection volume was 20μL; the temperature of the column was 25℃; DAD wavelength was 285 nm.The gradient started at 6% acetonitrile and 94% phosphate buffer in the first 5 min. Then the proportion of acetonitrile was up to 25% in 20 min staying for 2 min. After that, the proportion of acetonitrile was decreased to its initial proportion in 2 min. The verification test indicated this method has a high sensitivity, the accuracy is good, wide linear range(r>0.9996).(2) The single factor experiment and the orthogonal experiment were carried out in the article. The single factor experiment was to research the effect of extraction temperature,extraction time, solid-liquid ratio, extraction times on extraction amount. Orthogonal test showed that the best extraction condition was: temperature was 90 ℃; extraction time was10min; solid to liquid ratio was1: 5; extraction for 3 times.(3)This research determined the folate after 4 different processes: boiling frying and fresh-cut. The retention rates were frying(55.66±5.30)%、boiling(63.77±4.88)%、fresh-cut( 83.275±2.45) %. And the coefficient of variation were7.65 、 9.52 、 2.94 respectively. Thus fresh-cut was better than the other two methods for the retention of folic acid, which would become a new fashion.In the condition of storage, 4℃ is better than room temperature. In the first two days of storage, 4 ℃ storage of folic acid reduces slowly, but two days later decreased rapidly. When you buy some fresh vegetable that don’t eat immediately, they should be stored at 4 ℃so that the folate can be better absorbed, except cabbage. It should be eaten within two days.