Fatty acid composition of eggs enriched with omega –3 fatty acids on the market | Maščobnokislinska sestava jajc obogatenih z omega –3 maščobnimi kislinami na tržišču

English. The aim of our work was to determine fatty acid content in eggs enriched with omega-3 polyunsaturated fatty acids from various producers on the market. Due to simplicity, speed and reduced organic solvent usage, we used the in situ trans-esterification ISTE method for the determination of the fatty acid composition in eggs. The method was checked by the analysis of certified reference material CRM 164 (Anhydrous Milk Fat). The analytical results are in good accordance with certified values. The obtained results show that enriched eggs have a better fatty acid composition than average table eggs, regardless the producer. The ratio of FAs w -6 to w -3 in enriched eggs is less than 5, being 10 in ordinary eggs. An approximately equal content of alpha linolenic acid (18:3, n-3) was found in the enriched eggs from Jata Reja and Maia, 1.29 wt % and 1.25 wt % respect., while it was 11.28 wt % in the Fisher-Weppler’s eggs. The comparison of obtained results, the fatty acid content per 100 g egg content, with literature data is quite difficult, because authors calculate the content of FA in various ways. According to recent data from the literature (Weihrauch et al., 1977, Guardiola et al., 1994, Fatty acids, 1998, Kunachowicz et al., 1998), we have chosen a conversion factor of 0.83 in order to calculate the total fatty acids content in a 100 g egg content. The producers should declare the fatty acid composition, i.e. the content of w -3 PUFA-s, EPA and DHA on the package so that consumers are informed about the nutritional value of the food.

Slovenian. Želeli smo ugotoviti vsebnost maščobnih kislin (MK) v jajcih, obogatenih z w -3 maščobnimi kislinami različnih proizvajalcev na tržišču. Za določitev smo uporabili metodo plinske kromatografije in in situ transesterifikacijo maščobnih kislin. Ta tehnika je enostavna, hitra in omogoča majšo porabo organskih topil. Pravilnost in zanesljivost metode smo preverili z analizo certificiranega referenčnega vzorca CRM 164 (Anhydrous Milk Fat) in dobili dobro ujemanje rezultatov s certificiranimi vrednostmi. Ugotovili smo, da imajo vsa obogatena jajca, ne glede na proizvajalca,ugodnejšo maščobnokislinsko sestavo kot običajna jajca. Razmerje MK w -6/w -3 je pri obogatenih manj kot 5, pri navadnih pa okrog 10. Nekateri avtorji uporabljajo za izračun vsebnosti MK različne načine, zato je primerjava rezultatov zelo težavna. Glede na novejše literaturne podatke (Weihrauch et al., 1977, Guardiola et al., 1994, Fatty acids, 1998, Kunachowicz et al, 1998), smo za izračun vsebnosti MK v jajčni vsebini uporabili konverzijski faktor 0.83. Zaželeno bi bilo, da bi proizvajalci na embalaži navedli maščobnokislinsko sestavo, vsebnost w -3 večkrat nenasičenih MK, EPK in DHK in tako natančneje seznanili kupca s prehransko vrednostjo živila.