Preparation and characterization of folate-enriched eggs and egg yolk powders

In this study, a dose-response relationship between egg folate content and dietary folic acid content was observed. Folic acid supplementation did not affect egg quality or the performance of laying hens besides feed intake and feed/egg ratio. Vitamin C supplementation (150 mg/kg) promoted folate enrichment in the eggs, with a maximum value of 78 μg/egg being achieved. Moreover, there was no obvious effect on egg quality and an improvement in laying performance. Vitamin B12 supplementation did not affect egg folate content, suggesting there was already enough present in the original diet. The folate in eggs was relatively stable to degradation during storage, which was attributed to the protection provided by egg whites and eggshells. A folate-enriched egg yolk powder (803 μg/100 g) was prepared through spray drying in a nitrogen atmosphere. This powder was yellower, redder, and darker than one produced by spray drying in air and exhibited better storage stability. However, both powders exhibited similar water solubility and emulsifying properties. These results suggest that folate-enriched eggs and egg yolk powder could be used as functional foods for folate supplementation.