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Purification of egg yolk oil obtained by solvent extraction from liquid egg yolk
2014
Kovalcuks, A., Latvia Univ. of Agriculture, Jelgava (Latvia)
There are different methods of egg yolk oil extraction, but still solvent extraction is commonly used. Due to the high cost of egg yolk powder production, extraction of lipids from liquid egg yolk remains very topical. Crude egg yolk oil obtained by solvent extraction from liquid egg yolk contains high amount of water which can decrease shelf life of egg oil promoting lipid oxidation. High concentration of residual solvents limits the usage of egg oil in food or in cosmetics due to the health risks. The aim of this study is to purify egg yolk oil obtained by solvent extraction from liquid egg yolk. Results show that it is possible to decrease the water content in egg oil from 14.26 ± 1.29% to 0.88 ± 0.13% by eliminating lecithin from egg oil. Solvent evaporation in the rotary film evaporator under the vacuum cannot remove solvents completely from the extract, but nitrogen streaming through the extract as a last step in evaporation process removes solvent residues, leaving behind high quality egg yolk oil suitable for food application.
Afficher plus [+] Moins [-]Interaction of selenium and vitamin E in eggs and egg yolk oil
2013
Kovalcuks, A., Latvia Univ. of Agriculture, Jelgava (Latvia) | Duma, M., Latvia Univ. of Agriculture, Jelgava (Latvia)
In modern life oxidative stress has a serious effect on human health; therefore, natural antioxidants play an important role in human well-being. Hen (Gallus gallus domesticus) eggs can be effectively enriched with selenium and vitamin E and can be used as a source of natural antioxidants. The objective of this study was to determine the interaction of selenium and vitamin E in eggs and egg yolk oil. Two groups of Lohman Brown-Classic breed laying hens from a real production facility were taken as an experimental object. The basal diet was the same for both groups and content 25 mg kgE-1 of vitamin E added. 0.2 mg kgE-1 of sodium selenite was used as an inorganic source of selenium in feed for one hen group and 0.3 mg kgE-1 of organic selenium in the selenized yeast form for the other group. The selenium content was determined in eggs, egg yolk, egg white and egg yolk oil samples and vitamin E content in egg yolks and egg yolk oil. The results of this study indicate that there is no difference in selenium content in eggs from inorganic and organic selenium hen diet taking into account that selenium content in feed was different. The majority of selenium is located in egg yolk, but there was no selenium detected in egg yolk oil. Vitamin E content in egg yolks was not affected by the source of selenium (p is less than 0.05). High vitamin E content in egg yolk oil effectively protects egg yolk oil from oxidation during storage.
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