Thawornchinsombut Supawan, Park Jae W, Meng Guangtao, Li-Chan Eunice C Y
OSU Seafood Laboratory and Department of Food Science and Technology, Oregon State University, 2001 Marine Drive, Ste. 253, Astoria, Oregon 97103, USA.
J Agric Food Chem. 2006 Mar 22;54(6):2178-87. doi: 10.1021/jf0518958.
Structural changes of alkali-treated rockfish protein isolate (AKPI) during frozen storage were elucidated using a Raman spectrometer and scanning electron microscope (SEM). The results were compared to conventional surimi (CS). No significant textural difference was noted between AKPI stored at pH 5.5 and 7.0. The strongest texture was found for AKPI frozen with cryoprotectants and CS, while the weakest texture was observed in AKPI frozen without cryoprotectants. SEM revealed the most discontinuity in gels of AKPI with no cryoprotectants and a more aggregated microstructure after storage at pH 5.5 than at neutral pH. Raman spectral analysis demonstrated refolding of AKPI by pH readjustment to 7.0, although the refolded structure was not identical to that before the pH shift. CS showed higher alpha-helix content (approximately 50%) than AKPI (approximately 20-30%). Frozen storage induced a decrease and an increase in the alpha-helix content of CS and AKPI samples, respectively. AKPIs were slightly less stable than CS during frozen storage.
使用拉曼光谱仪和扫描电子显微镜（SEM）阐明了碱处理岩鱼蛋白分离物（AKPI）在冷冻储存期间的结构变化。将结果与传统鱼糜（CS）进行比较。在pH 5.5和7.0下储存的AKPI之间未观察到明显的质地差异。用冷冻保护剂冷冻的AKPI和CS的质地最强，而在没有冷冻保护剂的情况下冷冻的AKPI质地最弱。SEM显示，没有冷冻保护剂的AKPI凝胶中最不连续，并且在pH 5.5下储存后比在中性pH下具有更聚集的微观结构。拉曼光谱分析表明，通过将pH值重新调节至7.0，AKPI发生了重折叠，尽管重折叠后的结构与pH值变化前的结构并不相同。CS的α-螺旋含量（约50%）高于AKPI（约20-30%）。冷冻储存分别导致CS和AKPI样品的α-螺旋含量降低和增加。在冷冻储存期间，AKPI的稳定性略低于CS。
