| Diospyros kaki Thunb. is a valuable resource for traditional medicine and food use and commonly found in China. The plant possesses some pharmacological functions such as anti-bacterium, anti-inflammation, anti-cancer, anti-oxidation and so on.Polyphenols and terpenoids are predominantly contituents in persimmon peels, pulps and cores. In the processing, most of polyphenols come into the pomace. So there are abundant polyphenols in persimmon pomace. However, up to date, reports on separation and identification of effective compounds from persimmon pomace were terribly scarce. China has an abundant resource of persimmon pomace. For better development and utilization of the resource of Diospyros, this thesis use spectrophotometry to determine the contents of effective composition and research on the extraction technology of total polyphenols and antioxidant activity; at the same time, the chemical constitutions of persimmon pomace were separated and purified by chromatography, and the structure of the monomeric compounds were identified. The main results obtained from the experiments were as follows:1. The contents of total polyphenols, reducing sugar and soluble sugar of the persimmon pomace from Guangxi province were determined by spectrophotometry. The results showed that the content of total polyphenols of persimmon pomace were 12.580mg·g-1, and were 2.8 times higher than persimmon pulp from Shaanxi province; The content of reducing sugar and soluble sugar in the persimmon pulp from Shaanxi province were 239.038 mg·g-1 and 367.235 mg·g-1 respectively and distinct higher than the persimmon pomace. Polyphenols was the mainly active constituent, so there is a glorious prospect to produce polyphenols utilizing persimmon pomace.2. The technology of extraction polyphenols from persimmon pomace and antioxidant activity were studied in this paper. By the content of total polyphenols as the indication, the orthogonal experiment with different the ratio of solid to liquid, temperature, ethanol concentration, time on the basis of single-factor experiments were studied, and the antioxidant activity of persimmon pomace extract were measured with DPPH·method. The results showed that: influenceing degree of factors on the extraction effect were as follows: temperature﹥time﹥ethanol concentration﹥the ratio of solid to liquid; The optimum extracting conditions: the sample powder was extracted 2 times with 40 percent ethanol, 4h and 90℃each,solid-liquid ratio (v:w)20:1. Under this condition, the content of total polyphenols was 21.402mg·g-1; The radical scavenging activity of persimmon pomace extract was up to 95.4% at 0.24 mg·mL-1, and their reducing power was equivalent with Ascorbic Acid. These findings showed that persimmon pomace extract have strong antioxidant activity.3. Six compounds were isolated from the ethanol extract of the persimmon pomace from Guangxi province by CC, TLC, recrystallization and so on, which had been proved to be single compound by purity testing. Four of them were identified by modern spectroscopic techniques (1H-NMR, 13C-NMR, DEPT, MS) as follows: compound X1(βsitosterol), compound X2 (ursolic acid), compound X3 (scopoletin) , compound X4 (5-hydroxy-γ-pyrone-2-carboxylic acid), compound X5(gallic acid), compound X6 (myo-inositol).This thesis determined the contents of total polyphenols, reducing sugar and soluble sugar of the persimmon pomace from Guangxi province and pulp from Shaanxi province. The distribution of chemical constituents was preliminary definite. The optimal technological parameters of extraction total polyphenols from persimmon pomace were obtained. Six compounds were isolated from the ethanol extract of the persimmon pomace, which enriched the research contents. All the above results showed that persimmon (Diospyros kaki Thunb. ) pomace had high development and utilization value, and they were also useful for the further identification and rational utilization of Diospyros plants resources. |
PDF Full Text Request