A comparison study of egg enrichment efficiency and the bio-accessibility of bioactive compounds on farm fresh and commercial eggs

Abstract: The egg is an economical and accessible source of macro- and micronutrients naturally and through enrichment. The enriched nutrients confer additional health benefits beyond essential nutrition to the consumers. However, most studies have addressed the enrichment efficiency without considering their bio-accessibility in the small intestine. Thus, the study's primary objective was to evaluate how the bio-accessibility of whole egg-enriched compounds differs through the commercial supply chain compared to farm-fresh eggs. Standard and enriched (Omega-3 and Lutein) white shell (WS) and brown shell (BS) eggs were obtained from supermarkets in Lincoln, Nebraska, and from the poultry farm at the University of Lincoln-Nebraska. The eggs were cooked and subjected to in vitro gastrointestinal digestion. The eggs digests were analyzed for degree of hydrolysis (DH), peptides, carotenoids, and polyunsaturated fatty acids (PUFA) content. Significantly higher DH was observed in farm fresh eggs intestinal phase compared to commercial eggs. BS enriched boiled eggs tend to have higher peptide content compared to its fried counterpart in farm fresh and commercial eggs. Before digestion higher lutein content was observed in enriched cooked farm fresh and commercial WS fried eggs but its content decreased to non-enriched levels after digestion except for WS fried and BS boiled eggs. Cooked farm fresh eggs had a higher linolenic acid enrichment compared to commercial eggs, remaining stable during digestion for farm fresh but not commercial eggs. Farm fresh but not commercial eggs had docosahexaenoic fatty acid enrichment, which decreased after digestion for WS not BS eggs. Enriched compounds bio-accessibility was higher in farm fresh eggs compared to commercial eggs being boiling a suitable cooking method for BS and frying for WS. The study showcases the importance of processing and storage conditions of enriched eggs to deliver bioactive compounds while maximizing the absorption probability in the digestive tract for additional health benefits.