碩士 / 國立臺灣海洋大學 / 食品科學系 / 105 / Common antioxidants used in oil will lose their activity during frying, due to high temperature. Therefore it’s crucial to find a reliable antioxidant under this circumstance. The main purpose of this study is to produce chitosan sponge grafted with carbon nanotubes (CNT), and evaluate its antioxidant activity in high-temperature (180℃) soybean oil. CNTs with COOH and COCl group were obtained by treating with sulfuric-nitric mixed acid and thionyl chloride, thereafter underwent the grafting reaction with chitosan and Schiff-base chitosan (sCS). After the grafting reaction, CNT grafted chitosan sponge was acquired by lyophilization. FTIR and zeta potential analyzer was used to confirm the grafting reaction. SEM was used to observe the structure of sponge. DPPH scavenging assay, accelerated oxidation test and frying test was used to determine the antioxidant activities of sponges. FTIR spectrum and the results of zeta potential demonstrated that CNTs were successfully grafted on chitosan. SEM photo shows the porous surface of sponge, and CNTs presented on wall of chitosan sponge. DPPH assay indicated inferior antioxidant activity of grafted sponge comparing to BHT, but the results of accelerated oxidation showed that chitosan sponge grafted with CNT-COOH and CNT-COCl have p-anisidine value of 150.44 and 139.36. Both lower than BHT counterpart, which was 163. In terms of peroxide value, all of the grafted sponges have lower value than BHT. From the result of totox value, sponge grafted with CNT-COOH and CNT-COCl have the best antioxidant activity, their totox value are 150.44 and 139.36. In frying test, sCS sponge grafted with CNT-COCl (sCS-CNTCOCl) hold the lead of antioxidant activity among others. After 4 days of frying, p-anisidine value and total contents of polar compound for sCS-CNTCOCl were 69.86 and 18.3%. Test results demonstrated the antioxidant activity of CNT-chitosan sponge under long-term high-temperature condition.
| Identifer | oai:union.ndltd.org:TW/105NTOU5253056 |
| Date | January 2017 |
| Creators | Chen, Chia-Ho, 陳佳禾 |
| Contributors | Tsai, Min-Lang, Shieh, Yeong-Tarng, 蔡敏郎, 謝永堂 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 68 |
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