Studies On The Extraction,Purification And Determination Methods Of Phenolic Acids From Citrus Peels

In this paper, the content of phenolic acids in citrus peels of different varieties were analyzed by RP-HPLC. The extraction technique of phenolic acids was studied, and macroporous resin was applied to study primary purification of crude extracts. The main results are listed as follows.1. The RP-HPLC of 9 phenolic acids was identified. The chromatogram conditions includes HPLC(Shimazu LC-20AT), C18 column (VP-ODS,250x4.6mm,5um), the solution of 4% acetic acid and methanol (volume ratio 80/20) as the mobile phase, isocratic elution (speed:lml/min), diode array detector (DAD,260mm and 320mm), 10uL injection volume and 40℃column temperature.2. In this experiment, we systematically analyzed 15 citrus samples, including citrus reticalata, sweet orange, hybrid citrus and pomelo. It was found that the content of soluble phenolic acids in different citrus peels was the main part, the average content 232.67-5570.23ug/mL and accounted for 59.2%-88.1% of the total phenolic acids content. Among them, the highest content was ferulic acid, and the average content of 54.42-3462.75ug/g, followed by those coumaric acid and sinapic acid. The average content of insoluble phenolic acids was 145.94-815.82ug/g and accounted for 11.9%-40.8% of the total phenolic acids content.In the 15 citrus varieties, the phenolic acids content of the red sweet orange peel was 6386.05ug/mL and 16 times the lowest red meat pomelo. Followed by the common mandarin and red mandarin, its contents were 5089.56 ug/g and 4196.12ug/g.3. Applying ethanol as extracting solvent, effects of ethanol concentration, liquid-solid ratio, extraction temperature and time on extracting rate of phenolic acids were investigated by the technology of ultrasonic-assisted extracting. According to orthogonal experiment analysis, the optimum extraction processes of ethanol concentration, liquid-solid ratio, extraction temperature and time were obtained:70%,20:1,50℃and 25min respectively. On the optimum extraction processes, the yield rate of crude phenolic acids extracted from peel was 562.8ug/g.4. The character of 4 macroporous resins in purifying phenolic acids of orange peel was compared. The results showed that: LX-900 macroporous resin had the best results, and the optimized conditions and process route of purifying phenolic acids were injection concentration and flow speed were set as 200ug/mL,2.5mL/min, respectively; the eluent was 70% ethanol and the amount used was 400mL, purity was 90.62%.