椰浆中椰子蛋白的提取、分离和鉴定

为了更好地了解市售椰浆中椰子蛋白质量状况,本研究以市售的10种椰浆为样品,采用反向高效液相色谱（reversed-phase high performance liquid chromatography,RP-HPLC）及十二烷基磺酸钠-聚丙烯酰胺凝胶电泳（sodium laurylsulfonate-polyacrylamide gel electrophoresis,SDS-PAGE）对提取蛋白进行分析,采用基质辅助激光解吸电离飞行时间串联质谱（matrix-assisted laser desorption/ionization tandem time-of-flight mass spectrometry,MALDI-TOF/TOF-MS）对蛋白进行鉴定。结果表明：椰浆RP-HPLC约在10.4 min和11.9 min分别出现1个色谱峰,大多数样品峰面积大小都与蛋白标签含量一致,SDS-PAGE条带数量和颜色的深浅与RP-HPLC得到的峰面积结果一致,个别样品标签含量高,SDS-PAGE能分离出的蛋白条带数量也较多,但RP-HPLC的椰子蛋白峰面积小,经MALDI-TOF/TOF-MS鉴定,部分条带没有鉴定出椰子有关的肽段或蛋白。研究结果为椰浆蛋白的食品安全与质量控制提供了方法参考和示范。

Extraction,Isolation and Identification of Coconut Protein from Coconut Milk

In order to better understand the quality of coconut protein in commercially available coconut milk, 10 types of coconut milk were used as the samples bought from the market. Reversed-phase high performance liquid chromatography (RP-HPLC) and sodium laurylsulfonate-polyacrylamide gel electrophoresis (SDS-PAGE) were used to analyze the extracted proteins, identified through matrix-assisted laser desorption/ionization tandem time-of-flight mass spectrometry (MALDI-TOF/TOF-MS). There were two peaks in RP-HPLC of coconut milk at 10.4 min and 11.9 min, the peak area of most samples were consistent with the protein label content. The number of SDS-PAGE bands and intensity were consistent with the peak area results obtained by RP-HPLC. Some samples had high label content, and SDS-PAGE could separate more protein bands, but the peak area of coconut protein from RP-HPLC was small. The protein bands were identified with MALDI-TOF/TOF-MS and no coconut-related peptides or proteins were identified. This method could be used for the isolation and identification of coconut protein in coconut milk.