HIGHER CORRELATION WITH SENSORY EVALUATION OF OXIDATIVE RANCIDITY BY MODIFIED TBA TEST

When carrying out the TBA reaction test with oxidized lipids in the co nventional way, a red colour with maximum absorption at 530 nm is meas ured as degree of rancidity. This colour corresponds mainly to alkadie nals formed as products of oxidation. Before the formation of this red colour, a transient yellow colour with maximum absorption at 450 nm i s formed, which corresponds to both alkanals, alkenals and alkadienals , consequently having a ''broader'' and also higher sensitivity. By mo difying the conditions of the reaction (heating at a lower temperature , e.g. 2 hours at 50-degrees-C) the yellow colour becomes stable enoug h to be measured. The paper shows that the greater sensitivity of meas uring the yellow colour absorption corresponds to higher correlation w ith sensory evaluation, particularly in the case of low unsaturated sa mples.