Collaborative Studies on the Analysis of Lecithin by JOCS Official Method

Collaborative analyses of lecithin were conducted to establish a standard method for the Japan Oil Chemists' Society.Determinations of moisture, acid value, peroxide value, iodine value, acetone soluble matter and toluene insoluble matter of lecithin were carried out at ten different laboratories. All the data compiled showed good agreement except for those of moisture whose standard deviation showed considerable variation among laboratories. But this will not lead to any problems in practical applications in commercial transactions.The accuracy of acid determinations was increased by facilitating assessment of color change near the end point of titration. In the determinations of peroxide value and iodine value emulsification on shaking with water was prevented by adjusting the amount of sample and water. In the determination of acetone soluble matter, the lecithin sample had to be dissolved in exactly 2 mL of petroleum ether and washed thoughly with acetone.Good results were obtained by centrifugation instead of filtration using a glass filter for the ditermination of toluene insoluble matter.