碩士 / 國立臺灣海洋大學 / 食品科學系 / 100 / Grouper is an important role fish for tropical and subtropical reef district around the world. In recent years, the output of wild grouper was decreased, and the artificially cultivated grouper was increased gradually. Due to the Epinephelus coicoides’ flavor and tasty for consumers, and the benefits such as easily cultivating and rapidly growing, E. coicoides has become the main farming grouper species so far. In this study, the difference of chemical and flavor composition between wild and cultivated E. coicoides, and the quality of fish is stability on the cold environments were discussed.
The test specimens were collected from September, 2010 to August, 2011. The moisture content of wild E. coicoides in spring and summer was significantly higher than in autumn and winter, but cultured E. coicoides had no obvious seasonal variation. Cultured E. coicoides in summer and autumn ash content was significantly higher than in spring and winter, but it’s exist low seasonal differences in wild E. coicoides. The crude fat content in fall were higher than in the other seasons, and it no matter in the wild and cultured E. coicoides, and it’s more clear in cultured E. coicoides. The content of crude protein in cultured E. coicoides in summer was more than in spring and autumn conspicuously, but the trend of wild E. coicoides was moderate. The contents of free amino acid, nucleotides, and related compounds of E. coicoides was also detected. In the wild E. coicoides, content of nucleotides and related compounds in dorsal meat was 8.62 μmole/g, and it’s much higher than in ventral meat in summer time. But in the winter season, the results were totally opposite. The content of free amino acid was higher in winter and spring. Otherwise, in the cultured E. coicoides, nucleotides and related compounds of dorsal meat were higher than ventral meat in fall. The content of free amino acid was the highest in fall. To determine the flavor of tasty by the contents of IMP, glutamic acid, alanine and glycine, the flavor of wild E. coicoides in spring and summer was better than in fall and winter. Nevertheless, the cultured E. coicoides is delicious in fall and winter.
In order to observe the variation of total plate count (TPC), PH value, K value and volatile basic nitrogen (VBN), the E. coicoides was packed by the methods of air packing and vacuum packing, and then place in the environments of 0oC or 5oC for 14 days, respectively. The TPC could be maintained as limited value of 3 × 106 CFU/g in the environments of 0oC for around 14 days by vacuum packing. Furthermore, the air packing wouldn’t over the limited value at least 10 days. In the environments of 5oC, both of air packing and vacuum packing wouldn’t over the limited value about 7 days; and during the period of 14 days, the values of VBN were not beyond the sanitary requirements. Since the vacuum packing could keep the freshness index for almost 10 days in the environment of 0oC, and the result showed that the surroundings of low temperature and vacuum packing could extend the expiration date effectively.
| Identifer | oai:union.ndltd.org:TW/100NTOU5253035 |
| Date | January 2012 |
| Creators | Ying-Hsuan Chen, 陳映璇 |
| Contributors | Deng-Fwu Hwang, Tai-Yuan Chen, 黃登福, 陳泰源 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 79 |
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