南极磷虾蛋白质的分离特性及其组分分析

Recovery and composition of Antarctic krill Euphausua superba protein

利用pH调节法对南极磷虾Euphausua superba蛋白质进行分离回收,分别采取酸处理和碱处理冷冻南极磷虾,以蛋白质溶解度和回收率为分离特性参数,以0.5为pH变化梯度,探索在不同pH条件下南极磷虾蛋白质的分离规律。结果表明:酸处理和碱处理过程中南极磷虾肌肉蛋白质回收率无明显差别,在pH为1.5和12.0时有最大回收率,分别为49.8%和45.7%;通过SDS-PAGE分析,冷冻南极磷虾蛋白质主要为小分子质量蛋白质,主要分布在相对分子质量为80 000和35 000～45 000处,对比溶出物回收前后的蛋白质分子质量分布,发现采用酸处理法能回收大部分蛋白质组分,而采用碱处理法未能彻底回收,残液里还有多种蛋白质组分;通过对分离过程中南极磷虾含氮物的分布进行分析,表明用酸碱处理法分离蛋白的得率不高,分别占南极磷虾总粗蛋白质的37.76%和37.13%。

The protein in frozen Antarctic krill Euphausua superba was recovered by pH-shifting at a 0. 5 interval via acid and base and protein composition was analyzed by SDS-PAGE to explore the utilization of Antarctic krill. Feasibility of isolating krill protein with pH-shifting was evaluated using recovery of edible protein and yield of protein isolated as indexes. Results showed that there was no significant difference between acid-aided treatment and alkali-aided treatment in recovery of krill protein. The maximum recovery rate was obtained at pH 1.5 （49.8%） and pH 12.0（45.7% ）. The analysis of SDS-PAGE showed that composition of frozen kriU protein included mainly low molecular weight protein, approximately 80 000 and 35 000-45 000. The profile of protein molecular weight of dissolved and pro-dissolved substances was compared, indicating that the acid-aided treatment recovered most of protein, while the residues still present some protein unrecovered in the alkali-aided treatment. Finally, distribution of krill nitrogenous compounds in the isolation process was traced, and negative effect of pH-shifting on protein recovery was found with yield of 37.76% in the acid-aided treatment and 37.13% in the alkali-aided treatment.