Identification Of Polyphenols In Apple And Functional Properties

China is the largest producer of apple in the world. Shaanxi is one of the mainproduction areas, planting area, annual production and the export of apple concentrated juicelead the nation. Apple polyphenols have demonstrated to have potential beneficial effects onhealth. There have been some studies on the polyphenols; the most concentrated point is onthe functional activity of apple polyphenols, but the reported materials on the singlepolyphenol in apple and biological activity of each polyphenol and their antioxidant activityare very little.In the research, cellulase enzymolysis-citric acid extraction with ultrasonic-assistedtechnology was applied for polyphenols extraction from apple peel, the polyphenols ofsample in different tissues of apple were studied; A liquid chromatography with a diode arraydetector (DAD) method to simultaneously detect ten major polyphenols in apples has beenestablished; the change of polyphenols content in different periods and varieties of apple wereanalyzed; The changes of different apple varieties and different growth periods weredetermined; Resin adsorption was empolyed for purification of apple polyphenols; theantioxidant activity of different varieties of apples and different polyphenols evaluated bydifferent antioxidant activity method; Their antiproliferative activity evaluated by two cancercells.The main results are as follows.1. Cellulase enzymolysis-citric acid Extraction with Ultrasonic-assisted technology wasapplied for polyphenols extraction from apple peel, and response surface methodology wasused to optimize the conditions of polyphenols extraction. Efficiency of extraction wasoptimised by measuring total polyphenol content and three individual polyphenol. Theoptimal extraction conditions of polyphenols were determined as follows: Extraction time of37min, extraction temperature of37℃, enzyme amount2500U/g which was agreed closelywith the predicted value.2. This study developed a liquid chromatography with a diode array detector (DAD)method to simultaneously detect ten major polyphenols in apples. The linearity of thecalibration curves for each polyphenol in the desired concentration range was found to begood (r2>0.99). The method is accurate and precise with recoveries ranging from96.09%to 103.61%and both intra-day and inter-day variabilities (RSD<2%). The chromatographicparameters, such as flow rate, mobile phase pH and column temperature, were evaluated forrobustness and determined to be acceptable. The applicability of the proposed method wasdemonstrated by analyzing these10polyphenols in real samples such as Gala, Starkrimzon,Jonagold, Fuji and Qinguan from Baishui (Shaanxi, China).3. The content of polyphenols in different tissues were determined, there were thehighest content of polyphnols in apple peel, the lowest in apple pulp; The changes ofcompositon of polyphenols in different growth periods were analyzed. The results showedthat the proportions of all polyphenols were decreased during fruit development. The maindifferences of all apple varieties were the changes of the content of hyperoside, phloridzin,ellagic acid, chlorogenic acid.4. By studying the characteristics of adsorbing apple polyphenols with six resin, NKA-9was selected, the optimum conditions for separating and purifying apple polyphenol wereobtained. The results showed that when the content of apple polyphnols of test solution is1.46mg/mL, pH is original value，the moving speed is1.0mL/min and the eluting speed is0.5mL/min，the purity of apple polyohenols can be up to41.65%, it shows that the purity ofpolyphenol advance64times.5. The antioxidant activities of extracts from different apple varieties were studied,Nitroso Radical scavenging activity, DPPH· radical scavenging activity, hydroxyl radical(·OH) scavenging activity and Oxygen Radical scavenging activity. The chlorogenic acid,hyperoside, epicatechin show the stronger antioxidant power than those polyphenols.However, the antioxidant activities in vivo need to be further research.6. The antiproliferative effect of apple polyphnols against Caco2colon cancer cells andHepG2cells in vitro were analyzed. The results showed that the ranges of adequatefconcentrations were1mg/mL-64mg/mL. The effcets of antiproliferative of chlorogenic acid,phloridzin and epicatechin were better than other polyphenols.