Martín-Hernández Carmen, Bénet Sylvie, Obert Ladislav
Nestlé Research Center, Nestec Ltd., Vers-chez-les-Blanc, CH-1000 Lausanne, Switzerland.
J Agric Food Chem. 2008 Jun 25;56(12):4348-51. doi: 10.1021/jf7036888. Epub 2008 May 31.
Five methods using aqueous/organic solvents for the separation of proteins from oils were compared. The extraction with acetone-hexane followed by amino acid analysis was found to be the most suitable method for isolation and quantification of proteins from oils. The detection limit of the method was 0.18 mg protein/kg oil, and the quantification limit was 0.6 mg protein/kg. The relative repeatability limit for samples containing 1-5 mg protein/kg sample was 27%. The protein recovery ranged between 68 and 133%. Using this method, the protein content of 14 refined and nonrefined oils was determined. In none of the refined oils were proteins detected, whereas the protein content of the unrefined oils ranged between undetectable in extra virgin olive oil to 11 mg/kg in rapeseed oil. With sodium dodecyl sulfate-polyacrylamide gel electrophoresis in combination with silver staining, many protein bands were visible in the unrefined soy, olive, peanut, and rapeseed oil samples. Proteins bands were not obtained from the refined fish oil. In the other refined oil samples, a few proteins bands could be visualized. Two protein bands with apparent molecular molecular masses of 58 and 64 kDa were always observed in these oils.
比较了五种使用水/有机溶剂从油中分离蛋白质的方法。发现用丙酮 - 己烷萃取后进行氨基酸分析是从油中分离和定量蛋白质的最合适方法。该方法的检测限为0.18毫克蛋白质/千克油，定量限为0.6毫克蛋白质/千克。含1 - 5毫克蛋白质/千克样品的相对重复性限为27%。蛋白质回收率在68%至133%之间。使用该方法测定了14种精炼和未精炼油的蛋白质含量。在所有精炼油中均未检测到蛋白质，而未精炼油的蛋白质含量范围从特级初榨橄榄油中未检测到至菜籽油中11毫克/千克。通过十二烷基硫酸钠 - 聚丙烯酰胺凝胶电泳结合银染，在未精炼的大豆油、橄榄油、花生油和菜籽油样品中可见许多蛋白条带。从精炼鱼油中未获得蛋白条带。在其他精炼油样品中，可以看到一些蛋白条带。在这些油中总是观察到两条表观分子量分别为58和64 kDa的蛋白条带。
