| Summary: | 碩士 === 國立臺灣海洋大學 === 食品科學系 === 97 === The sea urchin Tripneustes gratilla, also called “uni”, is a common shallow–water species ubiquitous in Taiwan coastal area and subtropical zone. Because of its specific flavor of the gonad, it has been consumed worldwide. The purpose of this study was to understand the effect of seasonal variation (from May 2008 to March 2009) on the flavor and the reproduction period of T. gratilla gonad. Analysis including proximate composition, gonad index (GI), colour, fatty acid (FA), nucleotide related compound (NRC) and free amino acid (FAA) content. The data indicated that GI was the highest in July (16.5%) while the lowest value was 3.3% in February. The estimation of gonad colour by colormeter was nearly yellow-orange. Compared to the gonad colour of July (△value), there were significant difference in November and December. In FA analysis, C14:0 and C16:0 was the most abundant, and the main unsaturated fatty acid (UFA) were C16:1, C18:1, C22:1, C18:3, C20:4n6 and C20:5n3. While observed the change of UFA content, it was varied with seasonal change, polyunsaturated fatty acid got the highest content percentage in February 2009. In total FA content, the highest value observed was in August and the lowest in December. The main accumulation of NRC was IMP and GMP, IMP was higher from May to July while GMP was the highest in August. The most dominant FAA of sea urchin gonad was glycine, where alanine, valine, arginine and proline were the predominant FAAs. Arginine and valine was in increasing manner from September to February. Meanwhile glycine, alanine and glutamate also presented seasonal change. Total taste active compound content was the highest in November, then May and the lowest in August.
In conclusion, the gonad of Taiwan’s sea urchin T. gratilla could offer higher gonad content, the total taste active compound was higher and colour was better from May to July. It offers a consult for consumer that the better period for eating sea urchin T. gratilla gonad is from May to July.
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