碩士 / 國立海洋大學 / 食品科學系 / 88 / Changes of actomyosin (AM) complex forms of tilapia surimi as effected by holding treatment conditions during surimi preparations were investigated by the corperative uses of DSC, SDS-PAGE, and TSRM. The qualities of their gel products were studied by a food texture meter. WHC and folding ability of these gels were also tested. The holding treatments in effecting gel product qualities were elucidated.
Five representative types of AM resulted from holding treatments were found. Prior to the holding treatment, the surimi(2.5% NaCl added and 80% WC) prepared from tilapia of high freshness was found to possess typeⅠAM, 「dissociate AM」, whose F-actin(F-A) and myosin(M) were mainly monomeric forms. The gel strength of its gel product was only 547±50 g-cm. Upon subjecting it to holding treatments, two gelling-promoting types of AM complex were competitively formed. Among them, typeⅡ「test-tube brush type AM」 was found to be formed by grafting M to F-A with calcium bridges in surimi being aged at lower holding temperatures and catalyzed by calcium ion addition. The gel strength of the gel prepared from the typical surimi resulted by adding 3.5 mM calcium lactate and holding at 5℃ for 24hr was elevated to around 1000 g-cm. Whereas, type Ⅲ「TGase induced cross-linking AM」was found to be predominately formed in surimi with the addition of 3.5 mM calcium lactate and being held at higher temperatures. As high as around 1500 g-cm of gel strength could be obtained for the gel prepared from its representative surimi which was resulted from holding at 25℃ for 8hr. WHC and folding test results were found to be satisfactory and of no significant difference for all gels formed from above mentioned three types surimi.
Upon prolonged aging of surimi which had allowed formed typeⅡ AM to be formed during a holding treatment, two gel detrimental types of AM, types Ⅳ and Ⅴwere found. Among them, types Ⅳ was「aggregated AM」which was found in surimi whose TGase was activated only after the typeⅡAM complex formation, thus the subsequently activated TGase activity could cause only localized intramolecular inter-myosin covalent bondings formations instead of network type inhibition of gel formation. Whereas, the type Ⅴ「proteolyzed AM」was found for surimi whose a proteolytic enzyme was activated to cause AM breakdown. Both of these two types surimi were of low gel strength surimi.
| Identifer | oai:union.ndltd.org:TW/088NTOU0253024 |
| Date | January 2000 |
| Creators | Chi-Yi Ho, 何淇義 |
| Contributors | Ming-Sheng Kong, 龔鳴盛 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 100 |
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