| Our body can produce free radicals in the process of human metabolism, overproductionof the free radicals may lead to oxidative stress, resulting in degenerative diseases such ascancer, cardiovascular disease and alzheimer’s disease. A large number of researches havesuggested that the phenols in grain can effectively reduce the amount of free radicals, takinggrain such as wheat and rice can prevent the incidence of chronic diseases. Researches onantioxidant and antiproliferative activities of phenols in cereals had been almost extracted byorganic solvents, however, the changes and absorption of phenols in cereals during humandigestion haven’t been taken into account, thus the result cannot give a true picture of theantioxidant and antiproliferative activities of phenols in cereals in the body. This paper studiesthe changes of the antioxidant and anti-proliferative activities in wheat (wheat bran, wholewheat and refined flour) and rice (rice bran, brown rice and milled rice) during the humandigestive process by simulating in vitro.The main research contents and results are as follows:1. The effect of simulating in vitro digestion on the release of phenols and flavonoids inwheat and rice.Simulating in vitro digestion includes simulated gastric digestion and simulated intestinaldigestion, the extract were obtained respectively from wheat and rice in the two differentdigestion, then the release process and regulation of phenols and flavonoids in the extractwere studied systematically. Results showed that during simulating gastric digestion, thephenols release of wheat were rapidly increased in0.5h(p<0.05), increased significantly after0.5h, the phenols release of bran (318.93±3.95mg GAE/100g DW) was the highest in wheat.The phenols release of rice bran and brown rice were rapidly increased in1h(p<0.05),increased non-significantly after1h, the release of refined rice was gradually increased withdigestion time(p<0.05). The phenols release of rice bran (417.44±33.72mg GAE/100g DW)was the highest in rice. In this study, results demonstrated that the pH had no effect on therelease of phenols in wheat and rice, but pepsin played a vital role. The release process andregulation of flavonoids were different from the phenols. The flavonoids release of wheat and rice were rapidly increased in0.5h(p<0.05), increased non-significantly after0.5h. Theflavonoids release of bran (287.48±11.79mg CE/100g DW) was the highest in wheat, theflavonoids release of rice bran (1603.79±93.95mg CE/100g DW) was the highest in rice. ThepH had no effect on the release of flavonoids in refined flour and refined rice, pepsin played avital role. The pH had a certain impact on the release of flavonoids in the whole wheat andbrown rice, so it was with pepsin. The pH played a vital role on the release of flavonoids inbran and rice bran, while pepsin had no effect. During the simulated intestinal digestion, therelease of phenols and flavonoids in bran and rice bran did not change significantly(p>0.05),however, the release of phenols and flavonoids in the whole wheat, refined flour, brown riceand refined rice were rapidly increased in0.5h(p<0.05), increased non-significantly after0.5h.The release of phenols and flavonoids in bran (319.86±0.52mg GAE/100g DW and276.17±10.03mg CE/100g DW) were the highest in wheat. The release of phenols andflavonoids in rice bran (425.79±3.44mg GAE/100g DW and1574.32±61.64mg CE/100gDW) were the highest in rice. Trypsin and bile had played a vital role on the release ofphenols and flavonoids in the whole wheat, brown rice, refined flour and refined rice, but hadno effect on the release of phenols and flavonoids in bran and rice bran.2. The effect of simulating in vitro digestion on antioxidant activity of wheat and rice.The antioxidant activity regulation of extract in wheat and rice were studiedsystematically by using oxygen radical absorption capacity(ORAC) assay. Results showedthat during simulating gastric digestion, the ORAC value of extract in bran, the whole wheat,refined flour, rice bran, brown rice were rapidly increased in0.5h(p<0.05), increasednon-significantly after0.5h, the ORAC value of extract in refined rice was graduallyincreased(p<0.05). The ORAC value of bran (8064.43±258.18μmol TE/100g DW) was thehighest in wheat, the ORAC value of rice bran (5610.22±167.34μmol TE/100g DW) was thehighest in rice. The pH had no effect on the antioxidant activity of wheat and rice, but pepsinplayed a vital role. During simulating intestinal digestion, the ORAC value of extract in branand rice bran did not change significantly(p>0.05), the ORAC value of extract in the wholewheat, refined flour, brown rice and refined rice were rapidly increased in0.5h(p<0.05), and increased non-significantly after0.5h. The ORAC value of bran (8014.69±263.68μmolTE/100g DW) was the highest in wheat, the ORAC value of rice bran (5801.95±79.11μmolTE/100g DW) was the highest in rice. Trypsin and bile had played a vital role on theantioxidant activity of the whole wheat, brown rice, refined flour and refined rice, but had noeffect on the antioxidant activity of bran and rice bran.3. The antiproliferative of wheat and rice extract from process of simulating in vitrodigestion.The anti-proliferative effect of wheat and rice extract on CaCo-2were studiedsystematically. The results showed that the anti-proliferative effect of wheat and rice extracton CaCo-2was not obvious. |
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