不同热加工方式对刀额新对虾过敏原活性的影响

Study on effects of different thermal processings on immunocompetence of shrimp (Metapenaeus ensis) allergen

选取煮(100℃)、蒸(100℃)、高压(121℃,0.1 MPa)这3种常见热加工方法,分别处理刀额新对虾不同的时间,通过检测总可溶性蛋白、主要过敏原含量和免疫活性的变化,分析3种热加工方式对虾类过敏原免疫活性的影响,并通过质地剖面分析,研究虾肉经过处理后组织结构的变化。经过3种热处理后,分子量为36 ku的主要过敏原蛋白仍然存在,免疫印迹的结果显示其免疫活性有不同程度的下降,高压对免疫活性的降低程度最大,30 min时免疫活性降低了97%;在25～35 ku区域出现一条新的IgE结合蛋白。质构分析结果显示,经过高压热处理后,虾肉的硬度和咀嚼度都有很大程度的降低,口感变差。结果表明:热高压处理在降低虾过敏活性的同时,对其口感也有一定的影响,有必要通过优化高温高压处理工艺,在保持虾口感及营养的基础上,降低其过敏活性。

Shrimp proteins have been recognized as an important source of food allergens.The objective of this study was to analyze the immunocompetence and texture changes of shrimp allergen after different thermal processings.In this study,three heat methods were chosen to investigate their impacts on the immunocompetence of shrimp allergen,which included boiling,steaming,and autoclaving.After four different heating time,the total proteins and content of the major allergen were profiled by sodium dodecyl sulfate polyacrylamide gel electrophoresis（SDS-PAGE）.The changes of immunocompetence of shrimp allergen were determined by Western-blotting and ELISA.In the meantime,texture profile analysis（TPA）was adopted to compare the quality changes of the processed shrimps.The results showed that the major allergen protein was still present in all of the total proteins of shrimps.Moreover,there was a new protein with molecular weight of 25-35 ku,which took on high immunocompetence.However,based on the results of Western-blotting and ELISA,the immunocompetence of the allergen protein was all reduced after the three thermal processings.In addition,different processings had different impact on the immunocompetence.Among the three methods,autoclaving had the best reducing effect towards immunocompetence of shrimp allergen.Cooking 5 min with autoclave could reduce 78% of the immunocompetence,while boiling and steaming for the same period could reduce 53% and 23% of the immunocompetence respectively.Moreover,when the autoclaving time was extended to 30 min,97% of the immunocompetence was lost.Nevertheless,the results of TPA showed that the quality of shrimp had been destroyed during the autoclaving.The rigidity and chewiness of the shrimp was greatly reduced after the autoclave processing.It is concluded that autoclave can greatly reduce the immunocompetence of shrimp major allergen protein at the expense of destroying the texture.The parameters of the autoclave are suggested to be optimized to reduce the immunocompetence and keep good texture and nutrition.