Antioxidant Ability of Djulis Hull (Chenopodium formosanum) Extracts and Its Characterization for Starch
| Autor: | CHAN, YUNG-JIA, 曾勇嘉 |
|---|---|
| Rok vydání: | 2019 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 107 Djulis (Chenopodium formosanum) is an annual fast-growing underutilized pseudo cereal with a high percentage of starch content. Meanwhile, the hull removed from djulis was used in this study to assess the free radical scavenging and antioxidant capacity. The present study was constructed to evaluate the antioxidant activities of ethanol and water extract of hull and roots of djulis by using various in vitro methods. Ascorbic acid was used as the reference sample in the study. The extract samples were used at a concentration of 200, 400, 600, 800, and 1000 μg/mL. The total sugar content, total phenolic content, and total flavonoid content was determined. Antioxidant activity accessed by using the Trolox equivalent antioxidant capacity (TEAC), ferric reducing antioxidant power (FRAP), cupric ion reducing antioxidant capacity (CUPRAC), 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, and DMPD (N, N-dimethyl-ρ-phenylenediamine). RE and RW were significantly exhibited a high amount of total sugar, total phenolic, total flavonoid, and antioxidant capacity. Moreover, ROE and ROW was apparently confirmed with the moderate antioxidant capacity. However, limited antioxidant activities were detected on YE and YW. Djulis starch was extracted from the flour of dried grains by three different isolation procedures, which is: (1) hydrochloric acid (HCl) isolation procedure (HP); (2) deionized water isolation procedure (WP) and (3) sodium hydroxide (NaOH) isolation procedure (NP). Following by analyses for amylose content, morphological investigation, swelling power, crystalline properties, thermal and pasting properties. The amylose content of HP, WP, and NP was 22.14%, 24.15%, and 22.43%, respectively. The starch presented a polygonal shape, and with the granule size of 0.56-1.96, 0.74-3.02 and 0.62-2.48 μm, respectively. Djulis starch showed the classification of typical A-type X-ray patterns, and with the relative degree of crystallinity for HP, WP, and NP was 33.15%, 36.17%, and 37.42%, respectively. Differential scanning calorimetry analysis was used to determine the transition temperatures, transition range, and enthalpies of gelatinization of starches. The pasting properties were analyzed by using a Rapid Visco Analyzer. The dependence of swelling power for the three isolated starches on temperature was tested at 10 °C with the intervals between 60 °C and 90 °C. In short, NP isolation procedure with stable reaction is compelling in a technological point of view. The integrated procedure of isolation and the high yield of new types of starch from djulis might be attractive for commercial-scale production. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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