Studies On Functional Components,biological Activities And Simulated Digestion Of White,red And Black Quinoa

In order to understand and compare the biological activity and utilization effi-ciency of functional nutrients in differently colored quinoa(Chenopodium quinoa Willd.)seeds,the functional conponents content of quinoa,their antioxidant and anti-tumor activities,and the changes of phenolic compounds and antioxidant activity during simulated digestion were studied using white,red and black quinoa seed that are commonly sold in domestic and foreign markets as materials.It can provide a the-oretical basis for the food processing,breeding and consumption of quinoa.The mineral elements,saponins,and phenolic compounds of 5 varieties of 3 col-ors of quinoa were analyzed using national standard method,high performance liquid chromatography-mass spectrometry,high performance liquid chromatography,and Folin and aluminum chloride spectrophotometry.(1)Results showed that the most abundant minerals in quinoa were potassium and magnesium,which accounted for 76%and 20%of the total minerals respectively.The content of potassium in red and black quinoa was higher than that in white quinoa(p<0.05),and the content of potassium was significantly negatively correlated with the brightness value L^*(p<0.01).(2)The range of quinoa saponin content was 114.09?429.09?g OAE/g,and there was no correlation between saponin content and color parameters(p>0.05).(3)Red quinoa has higher free and free-conjugated phenolic acids(111.4?318.6?g/g and116.8?244.3?g/g),and black quinoa has higher bound phenolic acids(124.3?280.1?g/g).Ferulic acid is the main phenolic acid,with a maximum content of 206.90?g/g.(4)The content of total polyphenol and flavonoid in red and black quinoa were higher than that in white quinoa(p<0.05).The contents of phenolic acid,total polyphenols and total flavonoids in quinoa were negatively correlated with color parameters L^*?b^*?C and H°(p<0.01 or p<0.05),and the contents of phenolic acid and total flavonoids were positively correlated with the a^*value(p<0.01).From these results,it can be in-ferred that the content of potassium and phenolic compounds in quinoa seeds is relat-ed to color,and dark quinoa contains higher levels of potassium and phenolic com-pounds.The ABTS method,DPPH method and MTT colorimetric method were used to analyze the antioxidant activity of phenolic compounds and the anti-proliferation ef-fect of human breast cancer MCF-7 cells in 5 varieties of 3 colors of quinoa.(1)The results showed that ABTS free radical scavenging ability of quinoa phenolic com-pounds ranged from 1.40 to 22.10?M TE/g,DPPH free radical scavenging ability ranged from 2.70 to 18.80?M TE/g.The antioxidant activities of the free and bound phenolic compounds from red and black quinoa were higher than those of white qui-noa(p<0.05),and there was no significant difference in antioxidant activity of free-conjugated phenolic compounds among three colors of quinoa(p>0.05).(2)The IC₅₀ value of quinoa phenolic compounds on MCF-7 cells ranged from 107.72 to284.30?g/m L.The antitumor activity of the free phenolic compounds of black quinoa is greater than that of white and red quinoa(p<0.05),and there was no signifucant difference in the antitumor activity of free-conjugated phenolic compounds among three colors of quinoa(p>0.05),the antitumor activity of the bound phenolic com-pounds from red and black quinoa is greater than that of white quinoa(p<0.05).(3)Free,free-conjugated and bound polyphenols were positively correlated with their corresponding antioxidant and antitumor activities(p<0.01).From these results,it can be inferred that the antioxidant and antitumor activities of quinoa are related to color,and the dark quinoa seeds have higher antioxidant and antitumor activities.The release of phenolic acids,polyphenols and flavonoids,bioavailability and antioxidant activity of three colors of quinoa during simulated oral,gastrointestinal and intestinal digestion were studied by simulated digestion model.(1)Results showed that the release of phenolic acids,polyphenols and flavonoids from three col-ors of quinoa increased with the digestion progress.Phenolic acids and flavonoids re-leased more in the intestinal digestion stage,and polyphenols released more in the gastric digestion stage.The release of phenolic compounds from red and black quinoa was more than that of white quinoa(p<0.05).(2)At the end of simulated digestion,the release of phenolic acids,polyphenols and flavonoids were significantly different among white,red and black quinoa(p<0.05),which were 34.39,41.73,51.88mg/100g,362.19,400.40,436.62 mg GAE/100g,28.73,48.90,41.24 mg RE/100g,respectively.(3)At the end of simulated digestion,the bioavailability of phenolic ac-ids in white,red and black quinoa was 90.33%,85.41%and 91.61%,respectively.The bioavailability of polyphenols in white,red and black quinoa was 81.44%,84.09%and 78.75%,respectively.The bioavailability of flavonoids showed no significant difference among three colors of quinoa(p>0.05),which was about 20%.(4)During simulated digestion,the antioxidant activity(ABTS and DPPH free radical scaveng-ing capacity)of three colors of quinoa also increased with the digestion progress,and was positively correlated with the release of polyphenols(p<0.01).The antioxidant activity of red and black quinoa was higher than that of white quinoa(p<0.05).From these results,it can be inferred that the functional nutrients and antioxidant activity of phenolic compounds can be obtained by eating quinoa.Consumption of red and black quinoa could obtain more functional nutrients and antioxidant activity of phenolic compounds than white quinoa.