南极磷虾与鹰爪糙对虾酚氧化酶生化性质对比分析

Comparative analysis on the biochemical properties of phenoloxidase isolated from Euphausia superba and Trachypenaeus curvirostris

中文关键词: 黑变  南极磷虾  鹰爪糙对虾  酚氧化酶

英文关键词: Melanosis  Euphausia superba  Trachypenaeus curvirostris  Phenoloxidase

中文摘要:

      黑变是南极磷虾(Euphausia superba)贮运流通过程中的突出问题，为探究南极磷虾与普通海捕虾在黑变进程方面的异同，选取南极磷虾和海捕鹰爪糙对虾(Trachypenaeus curvirostris)作为研究对象，对2种虾在(2±1)℃贮藏过程中的黑变进程进行了感官评价，提取其酚氧化酶(PO)并进行了纯化，对2种虾PO的生化性质进行了对比分析。结果显示，冷藏条件下，24 h时南极磷虾的黑变已非常严重，黑变部位主要集中在头胸部、腹部甲壳以及尾节部分。72 h时鹰爪糙对虾的头胸部和尾节部分开始有轻微的黑变，之后逐渐扩散到躯干。南极磷虾和鹰爪糙对虾PO粗酶液经硫酸铵沉淀、Sephadex G-100凝胶过滤后，酶的纯化倍数分别达到17.22和19.67。2种虾PO的最适温度分别为30℃和40℃，南极磷虾PO在低温下仍具有较高的活力。二者的最适pH均为6.0~7.0之间。焦亚硫酸钠、亚硫酸氢钠、4-己基间苯二酚、L-半胱氨酸和抗坏血酸均可较好地抑制2种虾PO活力，其中，4-己基间苯二酚抑制效果最好。研究结果为南极磷虾冷链物流过程中的品质控制提供了依据，同时，为虾死后如何有效抑制其黑变提供了参考。

英文摘要:

      Melanosis is a prominent problem in the transportation and storage of Antarctic krill. In order to explore the similarities and differences in the process of melanosis between Antarctic krill and common sea shrimps, Euphausia superba and Trachypenaeus curvirostris were selected as research objects. A sensory evaluation of the melanosis process of the two shrimps during storage at (2±1)℃ were observed. The phenoloxidase (PO) was extracted and purified from the two species, the biochemical properties of which were further examined and compared. The results showed that the black spot formation was more serious in Antarctic krill under cold conditions at 24 h, and large areas of black spots were concentrated in the cephalothorax, abdominal shell, and tail of Antarctic krill. For T. curvirostris, slight black spots were observed in the cephalothorax and tail after 72 h, and then gradually spread to the whole body. The crude PO solutions of the two shrimp species were purified using ammonium sulfate and filtered through Sephadex G-100 gel. The purification fold of the PO solutions of T. curvirostris and E. superba reached 17.22 and 19.67, respectively. The optimum PO temperature was 30℃ for E. superba and 40℃ for T. curvirostris, respectively. The PO activity of Antarctic krill was higher at low temperatures and that of sea catch shrimp was higher at high temperatures. The optimum pH was between 6.0 and 7.0 for both species. Sodium metabisulfite, sodium bisulfite, 4-HR, L-cysteine, and ascorbic acid can all effectively inhibit the PO activity of the two shrimp species. Among these chemical reagents, 4-HR showed the best inhibitory effect on PO activity. The findings in this paper may provide a basis for the quality control during cold chain logistics of Antarctic krill, and also provide a reference for effectively suppressing melanosis in shrimps after death.