Research On Extraction Technology And Antioxidant Activities Of Sorghum Ployphenol

The optimized extraction technology conditions and antioxidant activities of sorghum polyphenol were studied, providing the scientific basis for the development and utilization of sorghum. The content of this article consisted of six chapters, and the author's contributions are in the following four aspects.1.Orthogonal experiments were performed and the results showed the optimal conditions of extraction as follows: 50℃of extracting temperature, 4 of pH value, 20 ratio of extracting solvent and material, 150 watts of ultrasonic power and 15min of extracting time. When the sorghum polyphenol extracts were purified by macroporous adsorbent resin, the optimum conditions of dynamic adsorption were 0.5 mg/ mL of concentration of sorghum polyphenol extracts, 2 BV/h of adsorption velocity, and desorption agent of 45% ethanol solution.2. Polyphenol compounds were extracted from the sorghum groats by water and methanol. Total phenolic content, reducing power, chelating activity, DPPH radical scavenging activity, ABTS radical cation scavenging activity and inhibition of hydroxyl radical-mediated 2-deoxy-D-ribose degradation of the extracts from the sorghum groats were determined. Total phenolic content in the extracts varied from 3.87% to 38.87%. DPPH radical scavenging activity, ABTS radical cation scavenging activity and reducing power of methanol extracts were higher than those of water extracts, while water extracts exhibited higher chelating activity compared with methanol extracts. It is also founded that sorghum groats extracts could inhibit the site-specific and non-site-specific hydroxyl radical-mediated 2-deoxy-D-ribose degradation, and the inhibition mechanism was varied.3. The effects of purified sorghum extracts on free radical-induced DNA breaks were studied using agarose gel electrophoresis experiments. The result showed that the purified sorghum extracts exhibited protecting effects on free radical-induced DNA breaks.4. Total phenol content, tannin content and antioxidant activity of the 13 kinds of sorghum extracts before and after germination were determined respectively, and the results showed that the germination had no essential effect on the total phenol content, tannin content, and antioxidant activity of the sorghum extracts.