碩士 / 國立臺灣海洋大學 / 食品科學系 / 94 / Abstract
The contents of histidine (His), anserine (ß-alanyl-1-methyl-L- histidine, Ans) and carnosine (ß-alanyl-L-histidine, Car) in margined flyingfish (Cheilopogon cyanopterus), whitefin flyingfish (Cheilopogon unicolor), yellowfin flyingfish (Cypselurus poecilopterus), sailfin flyingfish (Parexocoetus brachypterus), narrowhead flyingfish (Cypselurus angusticeps), stained flyingfish (Cheilopogon spilonotopterus) and glider flyingfish (Cheilopogon atrisignis) were analyzed in this stduy. Two specimens with bigger difference on chemical compositions were selected to investigate the changes of freshness and the formation of biogenic amines during storage at 4 and 25℃.
The moisture in seven specimens ranged from 75 to 79 % and protein from 20 to 24 %. Flying fish were lean fish with lipid content lower than 0.6 %. Flying fish were rich in His ranged from 232~473 mg/100g. The His contents of margined, sailfin, stained and glider flying fish were higher than 380 mg/100g, but their Ans and Car were relatively low. The compositions of free amino acids and dipeptides of whitefin flyingfish were different from those of the other species. It had a very high level of Ans (326 mg/100g) with the lowest amount of His. Both His and Ans in narrowhead and yellowfin flying fish were lower as compared to those of the other species. The contents of His, Ans and Car in dark muscle of flyingfish were much lower than those in white muscle. However, the former had a much higher amount of taurine than the latter. The content of His in margined flyingfish collected from Pintung were the highest, follow by those from Taitung and I-Lan. The whitefin flyingfish sampled from Pintung also had the highest contents of His and Ans, while those form Taitung were the lowest.
The pH values of white muscle of seven specimens ranged from 6.1 to 6.5. The white muscle of margined flyingfish, whitefin flyingfish, yellowfin tuna, tilapia and cobia had the highest buffering capacities in the range of pH 6-7. The buffering capacities of yellowfin tuna, margined flyingfish and whitefin flyingfish were significantly higher than those of tilapia and cobia. Flying fish and tuna had higher pH buffering capacities due to large amounts of His and Ans present in their white muscles.
The contents of aerobic plate count (APC) of margined and whitefin flying fish increased in logarithm when stored at 25℃ for 12 to 18 hour, and obious odors occurred at the 18th hour. The contents of volatile basic nitrogen (VBN) were higher than 25 mg/100g at the 18th and the 24th hours respectively, while the contents of ammonia increased significantly at the 24th hour. When stored at 4℃, the content of APC increased gradually after storage for 2 days, while the content of VBN increased drastically at the 6th day and was higher than 25 mg/100g at the 18th day. The content of ammonia had an obvious increase at the 12th day. The buffering capacities of white muscle in two species of flying fish decreased after storage for 18 to 24 hours and thereafter increased, which were associated with the stage of their initial decomposition.
Among the ATP-related compounds of margined and whitefin flyingfish, IMP was the most predominant compound at initial stage of storage and decreased rapidly after storage at 25℃ for 18 to 36 hours. The K values increased rapidly from 27.9 and 29.8 % to 91.7 and 71.2 %, respectively. As compared with those stored at 25℃, the changes of K values were significantly lower during storage at 4℃.
The contents of His of margined and whitefin flyingfish decreased after storage at 25℃ for 60 and 72 hours, but Ans remained changed. The content of His did not change significantly when storage at 4℃. The amounts of free amino acids gradually increased during storage at 25 and 4℃. Ornithine (Orn) was not detected in flying fish muscle; however, it was found in a considerable amount at the stage of initial decomposition. Therefore it might be used as an indicator for freshness and degrees of decomposition. The biogenic amines of margined and whitefin flyingfish, including putrescine (Put), cadaverine (Cad) and histamine (Him) were the most predominant compounds during storage. Their precursors were Orn, lysine (Lys) and His, respectively. The decreased mole of His was almost equal to the increased mole of Him. The biogenic amine index (BAI) values of two species of flying fish were 0.81 and 0.65 after storage at 25℃ for 24 hours, which were close to 1, the hazard value induced scombroid poisoning. The values increased to 6.13 and 3.17 at the 36th hour of storage, respectively. When stored at 4℃, the BAI values of margined and whitefin flyingfish reached the hazard value at the 13th and the 15th day.
| Identifer | oai:union.ndltd.org:TW/094NTOU5253004 |
| Date | January 2005 |
| Creators | Jing-Ting Tsai, 蔡敬廷 |
| Contributors | 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 | 112 |
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