碩士 / 國立屏東科技大學 / 食品科學系 / 94 / Fish balls and other surimi products are mainly made of fishes in Taiwan Distribution channel. Only few products are made of squids or other invertebrates. One of the reasons is that fishes have better gel-forming ability than squids for making surimi. Some reports have showed that the gel strength of squid’s surimi reaches the highest point at 70℃. Even the temperature was higher than 70℃, the gel strength wouldn’t increase. And it was the limited effect to extending the heating time in increasing of gel strength. Two-stepped heating way showed the gel strength would be lower remarkably. But the addition of trypsin inhibitor、EDTA or PMSF to squid’s surimi would suppress the lower gel strength through two-stepped heating way. During two-stepped heating way, it seemed to be found that the decreasing of gel-forming ability in squid have a close relationship with the proteases in muscle. Therefore, this study would focus the proteases in squid’s muscle. The decreased gel–forming ability be caused by proteases would be discussed in this study. At the same time, the character of refined protease would be discuss.
This study use the refrigerated fresh squid, and then the sample solution would be extract with 20mM Tris-HCl buffer after the squid was grinded. The sample solution could be drawn by use centrifuge and dialysis. The refined enzyme could be down by ammonium sulfate salting out, gel filtration and ion exchange chromatography. The effect of enzyme activity enzyme would be studied by the concentration of salt, pH, the heating temperature in the crude and refined enzyme. The degrade situation of the enzyme in the actomyosin of swordfish would be investigated by SDS-PAGE.
The result of study showed that the crude enzyme activity of squid’s muscle was the highest at pH 7. The optimum temperature was 40℃ and 70℃ in bovine albumin. And in Casein, it was 35℃ and 70℃. The highest activity would be reached at 0.1M of salt concentration. The optimum temperature of the refined enzyme was 40℃ in the substrate of synthetic peptide（Boc-Val-Leu-Lys-MCA）as same as Casein. The optimum pH value was near 7.9 in synthetic peptide. And it was near 6.8 in Casein. The Nα- tosyl-L-Lys-chloromethyl ketone (TLCK ) and soy trypsin inhibitor could effectively suppress the hydrolysis of synthetic peptide. And the soy trypsin inhibitor could suppress the hydrolysis activity of Casein effectively. This Enzyme could hydrolysis the myosin heavy chain of swordfish at neutral pH. From the above result, the bad gel of squid surimi had the relationship with metallic protease, it also had the relationship with the similar trypsin protease.
| Identifer | oai:union.ndltd.org:TW/094NPUST253004 |
| Date | January 2006 |
| Creators | Li-Kuei Tsao, 曹理貴 |
| Contributors | Wen-Kuei Chiu, 邱文貴 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 67 |
Page generated in 0.0087 seconds