In vitro digestion of folate in yolk and granule fraction as tested in a dynamic, computer-controlled model of stomach and small intestine

Abstract

In our previous studies, we showed that egg yolk fractionation by centrifugation can lead to complete separation of folate in granule fraction of egg yolk which has two folds more protein than egg yolk. Folate in egg yolk presents in the form of 5-methyltetrahydrofolate (5MTHF), a predominant type of highly available form of folate. However, evidence is lacking as to the bioaccessibility of the 5MTHF in granule fraction separated through water-based fractionation technique. Thereby, a dynamic and computer-controlled gastro-small intestinal system was used to study and compare the distribution of 5MTHF throughout intestinal compartments during digestion of egg yolk and granule fraction in their native form. As granule fraction of yolk composed of higher protein content compare to egg yolk, the dialysis profile of protein change during the process for yolk and granule was determined. The 5MTHF was stable during digestion with average recoveries of 58% and 42% in granule and yolk, respectively. The present work is the first to present data on the bioaccessibility of natural folate from egg yolk granule and shows the potential of egg yolk granules as «natural» delivery system of 5MTHF.