Study On The Extraction Purification And Detection Of Polyphenols In Potato

Potatoes are one of the world's four major food crops.We always use the peeled potatoes in our daily lives and production,while the skin is discarded as waste.However the skin and slag have contained lots of bio-active ingredients which are very valuable. To make good use of potatoes,extraction and separation-purification technology were studied on main bioactive compounds-Phenols in this paper,and a quick method to separate and to test phenols-High Performance Capillary electrophoresis(HPCE) was stated.Chlorogenic acid and Caffeic acid were found in the potatoes by the qualitative experiment of Thin Layer Chromatography (TLC).The relevant literature and the TLC results revealed that phenols in potato mainly is chlorogenic acid.Then extracted phenols through such approaches as refluxing extraction,water bath shaker oscillating extraction,ultrasonic wave assisted extraction.We compared the three methods and determined the best extraction method.As a result,the ultrasonic wave assisted extraction was the best extraction technique,the parameter as follows:70% ethanol as extraction solvent,pH =3,ratio of material to liquor 1/12 g/ml,the ultrasonic wave power 175W,the extraction temperature 45℃,the time for 40min,to extract 3 times.Phenols were purified by column chromatography separation.We compared two kinds of filler-macroporous resin and polyamide,found using polyamide as the filler was better when the absorption and desorbing.The influences of pH value,concentration of sample and velocity of flow in the static and dynamic adsorption experiment were investigated.The result showed that:the pH value of absorbing and eluting was 3;the best concentration of sample was 0.9711mg/mL;the absorbing velocity of flow was 2.0mL/min;the purification with distilled water(1～2times the volume of the polyamide), and then,with 50% ethanol(6～8times the volume of the polyamide) was used to elute polyphenols of potatoes;and the eluting velocity was 2.0mL/min.A high performance capillary electrophoresis method has been developed for the simultaneous separation and determination of six phenolics of rutin,quercetin,chlorogenic acid,caffeic acid,gallic acid and protocatechuic acid.The effects of several factors such as the pH and concentration of running buffer,the separation voltage and the runnion tamperation on HPCE were investigated.Under optimum condition,the running buffer consisted of 20mmol/L NaH₂PO₄-20 mmol/L Sodium borate,pH 7.5,separation voltageat 20kV,running temperation at 30℃,the UV detection wavelength was 214nm.The results showed that the six analytes can be well separated within 12.0min,each one had a good linear relationship (R²=0.9987～0.9874).The RSD of migration time was 0.280%～0.425% and of the peak area was 5.228%～8.506%.The average recovery percentage was 85.11%～101.98%.The HPCE result told us that the mainly polyphenol in potatos are chlorogenic acid and caffeic acid,each of their content was 330.18μg/g and 89.33μg/g.The total content of polyphenol in potatos were 419.51μg/g.