DETERMINATION OF UV ABSORPTION AT 232-NM, FATTY-ACID COMPOSITION, TRILINOLEIN AND TRIGLYCERIDES OF 42 EQUIVALENT CARBON NUMBER IN OLIVE ANDOLIVE-RESIDUE-OILS - STATISTICAL ASSESSMENT OF THE PRECISION CHARACTERISTICS FROM A COLLABORATIVE TRIAL

Some analytical methods for the determination of olive oil characteris tics included in the European Union and International Olive Oil Counci l regulations lack precision data. To overcome such inconvenient a col laborative trial was set up including 22 laboratories from governament al institutions and industries. UV absorption at 232 nm, fatty acid co mposition, trilinolein and triglycerides with 42 equivalent carbon num ber were the tried methods. Repeatability and reproducibility data wer e obtained using the statistical method included in the International Standard ISO 5275/1986 (E). The effect of oil purification through a s ilica gel column on K232 and triglycerides was also studied. Finally f or fatty acid determination, methylations by cold methanolic potash an d by heating with methylated sodium were compared.