碩士 / 國立臺灣海洋大學 / 食品科學系 / 98 / The preserved mullet roe is a traditional Taiwanese gourmet and has very high market value. However, the mullet after removing the roe lost most of its value and sometimes even was discarded as animal feed. This study was focused on developing and evaluating the production condition of smoked mullet flesh and monitoring the changes of chemical compositions and color during smoking process, as well as volatile basic nitrogen (VBN), pH value, ATP related compounds, microbiological counts and appearance during storage, in an effort to find an indicator to define the shelf life of the smoked mullet product. The results showed that raw material (with or without skin) decreased moisture in the smoking process which increased the relative content of protein and lipid. The “L” value (brightness) and whiteness were significantly increased while “a” value (redness) and “b” value (yellowness) were decreased after steaming process. As smoking with sugar, the “L” value and whiteness were decreased while “a” and “b” values were both increased. The salted process was found to improve the texture, flavor and overall acceptance of the product. Final product has a golden color like the other traditional gourmet - smoked shark. However, the color was too dark when smoked with dried tea leaves in the purpose of adding more flavor. Samples of smoked final product were stored at 4℃ and 25℃ respectively. It was found that, at 4℃, pH value and VBN did not vary much throughout the 15-day testing period. On the other hand, when storing at 25℃, the VBN increased dramatically in day 3 and the amount of TMA was increased with the storage time as pH value changed slightly. That indicated that TMA could be a possible indicator for defining shelf life. In the initial stage of storage test, the “L” value was increased, “a” and “b” values were decreased as the whiteness was increased. No significant changes were found for “L”, “a” and “b” values after the initial stage. The ATP related compounds found in raw material were mainly IMP and inosine with some ADP and AMP. The composition of those compounds was not significantly altered during the process. Hypoxanthine and K value only slightly increased in storage test at 25℃. Hence, they were not suitable for evaluating the quality of the product. Since the TPC and coliforms were higher than the limit standard in the second day of storage test at 25℃. Here the recommended shelf life at 25℃ is 2 days and 15 days at 4℃.
| Identifer | oai:union.ndltd.org:TW/098NTOU5253048 |
| Date | January 2010 |
| Creators | Hui-Fang Kuo, 郭惠芳 |
| Contributors | Chyuan-Yuan Shiau, 蕭泉源 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 84 |
Page generated in 0.0022 seconds