加熱及加壓處理后吳郭魚肌動凝蛋白之變性現象

Denaturation Phenomena of Tilapia Actomyosin Due to Pressurizing and Heating

游啟政(Chi-Cheng Yu) ； 朱聖哲(Sheng-Zhe Zhu) ； 謝泓鈞(Hung-Chun Hsieh) ； 柯文慶(Wen-Ching Ko)

《臺灣農業化學與食品科學》 42卷2期 (2004/04) Pp. 98-104

https://doi.org/10.6578/TJACFS.2004.014

摘要

以國產吳郭魚為材料，萃取其普通肉之肌動凝蛋白(actomyosin,AM)，觀察其於低溫高靜水壓(4℃、50-300MPa)及加熱(25-75℃)處理後之變性現象。結果顯示加熱及加壓皆會導致AM變性，僅是變性程度有所不同。溫度升高時，AM溶液之濁度(turbidity)亦升高，而升高壓力（至300 MPa止）則否，表示此壓力下並不使得AM分子間如同加熱般劇烈聚合成大分子而使濁度上升。AM之表面疏水性(surface hydrophobicity)會因加熱及加壓而增大，表示兩者皆會促使分子結構改變，但在300 MPa以下，AM疏水基暴露之程度低於加熱處理。42℃加熱或50MPa以上加壓，AM之黏度 (viscosity) 隨處理時間而迅速下降，顯示此時AM之分子結構已改變。另由ATP感度 (ATP sensitivity) 及超沈澱 (superprecipitation) 試驗可知，AM具有之結合 (association) 與解離 (dissociation) 特性於45℃加熱處理10 min或100 MPa加壓處理20 min均幾乎消失。

關鍵字

吳郭魚 ； 肌動凝蛋白 ； 靜水壓 ； 變性

並列摘要

Actomyosin (AM) was extracted from ordinary muscle of tilapia to investigate the denaturation phenomena due to pressure (4℃, 50-300MPa) and heat (25-75℃) treatments. Both heating and pressurizing resulted in the denaturation of AM, but the degree varied. The turbidity of the AM solution increased with the increase of temperature, but no obvious change was observed as the pressure changed (down to 300MPa). Also, the pressure did not cause AM to form strict intermolecular aggregates as heating. The surface hydrophobicity of AM increased under the pressure and heat treatment due to a change in the conformation of the molecules. The degree of exposure of the hydrophobic group under 300 MPa was lower than that caused by the heat treatment. Changes in molecule conformation were also observed as the viscosity declined due to heating at 42℃ or pressurizing at 500 MPa. The association and dissociation characteristics of AM almost disappeared with heating at 45℃ for 10 min or pressurizing at 100 MPa for 20 min according to the of ATP sensitivity and superprecipitation test.

並列關鍵字

Tilapia ； Actomyosin ； Hydrostatic pressure ； Denaturation