Nutritionally important fatty acids in hen egg yolks from different sources.

Egg samples were collected from six different sources across Canada, and the yolks from those samples were analyzed for fatty acid composition using gas chromatography. Three yolk samples were from regularly fed chickens from three different Canadian egg processing plants, and the other three samples were from chickens fed with special diets. The specially fed chicken yolk samples were collected from three different Canadian egg producers. The three egg yolk samples from specially fed chickens had a significantly higher linolenic acid and docosahexaenoic acid content than the three regularly fed chicken yolk samples (P < 0.05). However, the arachidonic acid levels in the regularly fed chicken yolk samples were significantly higher (P < 0.05). In general, there was no significant difference among the three egg sources in each group. There was some variation in the fatty acid levels during different seasons for each source, but the difference was not statistically significant in most cases.

Separation of egg yolk immunoglobulins using an automated liquid chromatography system.

An automated liquid chromatography system was developed to carry out the separation of an egg yolk immunoglobulin (IgY) using cation exchange media. Industrially separated egg yolk was diluted 10 times with distilled water, the pH adjusted to 5.5, and the water-soluble protein fraction separated from lipoproteins by sedimentation. The supernatant was filtered and then applied to a column packed with a cation exchanger within an automated liquid chromatography system. Different operating conditions were investigated using phosphate buffer in order to assess the effect on recovery and purity. Fractions as pure as 80% could be collected and a recovery of the chromatography step of about 65% was obtained for a purity of 60% using either a linear or step gradient. The overall recovery for the process was 34% if one-step dilution/extraction is used for lipoprotein separation by sedimentation, and 51% if two-step dillution/extraction is used. Further improvement of the yield to about 60% is possible using centrifugation for lipoprotein separation. The automated system confers many advantages, the key elements being the time savings and accurate control of the process.