The determination of lutein, zeaxanthine, canthaxanthine xanthophylls in egg yolk and interactions between Hunter Lab color parameters: I. The research on the determination of heat

In this study, lutein, zeaxanthine, canthaxanthine xanthopylls in industrial egg yolksconsumed in our country were determined by developed high performance liquidchromatographic-diiyode array (HPLC-DAD) method and color data of the above-mentioned eggyolks was also determined by Hunter-Lab colorimetric method. In medium egg yolks that have61.04 ± 0.22 g of average total weight and 17.84 ± 0.13 g of yolk weight; lutein, 527,56 -1144,74µg/yolk (avg. 915,24± 1,42); zeaxanthine, 7,38-18,09 µg/yolk (avg. 13,98± 0,23) andcanthaxanthine 7,73-18,81 µg/yolk (avg. 11,70± 0,10) were determined, based on the dryweight. In raw egg yolk, color parameters containing 68,63-72,97 (avg. 70,41± 2,57) of L(lightness) value, 25,20- 29,42 (avg. 26,81± 5,07) of a (redness) value and 74,29-77,50(avg.75,16±4,70) of b (yellowness) value were determined; the statistically comprehensiblecorrelations were determined between those and the levels of color compounds and alsoestablished the correlation and the linear regression parameters (p<0.01).In our research that examined the alterations of lutein, zeaxanthine, canthaxanthinecolor compounds and of Lab color parameters in soft-boiled egg and hard-cooking egg throughheat process effects, the percentage xanthopyll degredations were also detected. Lutein wasdecreased as 38.08% in soft-boiled yolk and as 51.32% in hard-cooking yolk whereaszeaxanthine was reduced as 22.49% in soft-boiled, as 46.61% in hard-cooking yolk andcanthaxanthine was decreased as 6.99% and as 45.80% in soft-boiled and hard-cooking yolk,respectively (p<0,01). Due to the long heat process, the degredations in hard-cooking form werehigher than that of soft-boiled. In research content, lutein/ zeaxanthine (L/Z) proportions in rawegg yolks as 59.34 /1 - 71.48 /1 (avg. 65.47 /1) whereas in soft-boiled form as 57.11 /1 and inhard-cooking form as 65.19 /1.From this point of view, with the determined xanthopyll amounts and color parameters,the position evaluation and interpretation was verified concerning chemicals levels which colorformed in egg yolks.Key words : HPLC-DAD, Hunter-Lab, Canthaxanthine, Lutein, Egg yolk, ZeaxanthineI