Study Of The Effect Of In Vitro Digestion On Antioxidant Activity And Antiproliferative Activity Of Apple And Pear

Taking into account of transformation and degration of antioxidants during the digestiveprocess and to reflect real antioxidant and antiproliferative activty of fruit, whole fruit, flesh,peel of apple and pear were subjected to simulated gastrointestinal digestion, antioxidants(polyphenols, flavonoids), antioxidant activity (ORAC) and antiproliferative activity duringdifferent stages of the digestive process were studied in this thesis, the role of chemicalenvironment and digestive enzymes in the digestive process were also studied.The main research contents and results as follows1) The effect of simulated gastrointestinal digestion on antioxidant content of appleand pearA reasonable mimic digestion model including gastric and intestinal digestion stage hadbeen developed. The releasing of polyphenol and flavonoid from apple and pear whole fruit,pulp, peel during gastric and intestinal digestion was studied. The results showed that: duringgastric digestion stage, the release of polyphenol from apple and pear was similar toflavonoids.The digestion group was increased significantly (p<0.05) at the beginning0.5h,the control group declined significantly,while the acid group keeped or increased slightly.Thepear peel was the highest to be116.33±2.22mg GAE/100g，503.78±8.96mg CE/100g forpolyphenol and flavonoids,respectively. During intestinal digestion process, the polyphenolof the digestion and the control group increased, the digestion group was higher than thecontrol group. The trendcy of flavonoids was always increased first and then declined duringintestinal digestion process. The chemical environment of the gastrointestinal tract anddigestive enzymes had played a significant role in promoting the release of polyphenol andflavonoids. Polyphenol and flavonoids were more stable in gastric acid environment than inintestinal mild alkine environment.2) The effect of simulated gastrointestinal digestion on antioxidant activity of appleand pearORAC (oxygen radical scavenging method) was used to determine the changes ofantioxidant activity of whole fruit, pulp, peel of apple and pear during digestion process. Theresults showed that: during gastric digestion and intestinal digestion process，the antioxidant of apple and pear whole fruit, pulp and pear peel was reached equilibrium after1h digestion(p>0.05). The trendcy of ORAC was similar to polyphenol.The pear peel got the higestamount to be2459.77±70.05μM TE/100g.The chemical environment of the gastrointestinaltract and digestive enzymes had played a significant role in promoting the increasing ofantioxidant. There was a good correlation between antioxidant activity (ORAC value) andpolyphenol content.3) The effect of gastrointestinal digestion on antiproliferation to human colon cancercells Caco-2of apple and pearAntiproliferation to human colon cancer cells Caco-2of whole fruit, pulp, peel of appleand pear during simulated gastrointestinal digestion was studies. The results showed that bothbefore and after gastric digestion, whole fruit, flesh, skin of apple and pear didn’t haveantiproliferative activity range the exist concentration. During intestinal digestion process,besides the control group, other samples had dose response range the exist concentration.Apple skin got the highest antiproliferative activity to be47%at the concentration of56mg/mL. Intestinal digestion could significantly enhance antiproliferative activity of appleand pear and digestive enzymes had played a vital role. During intestinal digestion process,whole fruit was always showing higher antiproliferative activity than peel then pulp.