碩士 / 國立臺灣大學 / 食品科技研究所 / 87 / Rehydrated squids, prepared by pickling the dried squid in a Na-hydrogen carbonate solution, is usually served as raw materials for cooking and is one of the major consumption ways of squids in Taiwan. However, alkali treatments of proteins usually cause the crossing-linking reaction, degradation, browning reaction and, especially, racemization of compositional amino acids in proteins of squids those are originally rich in essential amino acids and thus, lead to the decline of protein nutritional values. Enatiomers or epimers of analytes were reported to be completely separated and identified through the modifications of partition coefficient between buffer solution and neutral analytes micelles formed by the application of surfactants in 1984. Therfore, the techniques of micellar electrokinetic capillary electrophoresis(MECC) for separating enatiomers or epimers have been improved and become much mature since then.
In the present study, MECC was used to analyze the 9-fluorenylmethyl chloroformate (FMOC) derivatized amino acids by altering the factors such as wavelength, voltage, surfactant level and organic modifier level in the electrolyte solution. The optimal separation conditions was 50 mM SDS-12 mM β-CD-50 mM phosphate buffer (pH 7.5) of electrolyte solution, 15 kV for applied voltage, 25 ℃ for operating temperature, and a silicated capillary with 50μm in diameter and 67cm in length. Enantiomeric separation of enantiomers of methionine, valine, isoleucine, leucine, phenylalanine and tryptophan were complete, however, separations of enantiomers of threonine and lysine were failed in the such model system. Addition of 45 mM β-cyclodextrin and 1 M urea improved the enantiomeric separation of lysine and proline (Rs > 1.0).
Using rehydrated squids, prepared under various temperatures (room temperature, 50℃) and alkaline levels (sodium carbonate/sodium hydrogen carbonate buffer, pH 9.0, 10.0 and 11.0) as real system, enantiomeric separations of FMOC derivatized amino acids were conducted to elucidate the effects of processing condition on the formation of amino acid enatiomers. Results showed that the enantiomerations of valine, phenylalanine, methionine, lysine, leucine, isoleucine, glutamic acid, aspartic acid alanine and arginine in the compositional amino acids of rehydrated squids in both control and experimental group were not apparent suggesting the nutritional loss due to enantiomeration of the commercial rehydrated squids, pickled with NaHCO3 (pH 8.9) at ambient temperature ,was negligible.
| Identifer | oai:union.ndltd.org:TW/087NTU00252017 |
| Date | January 1999 |
| Creators | CHING-WEI CHANG, 張晉瑋 |
| Contributors | Hung-Min Chang, 張鴻民 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 110 |
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