The use of high hydrostatic pressure to generate folate-enriched extracts from the granule fraction of hen's egg yolk

- The effect of physicochemical and technological treatments on microstructure of egg yolk granule was studied.
- High pressure treatment caused disintegration of granule microstructure.
- The stability of folate in granule under pressure was estimated.
- The structural characteristic of granule from egg yolk was better understood.

The present work characterized the effects of pre-treatments on the protein profile and microstructure of granule fractions from egg yolk. The granule microstructure was studied using confocal laser scanning microscopy (CLSM). The protein profiles of the pre-treated granule and the corresponding plasma fraction were studied using 2D gel electrophoresis techniques. Further, we explored the potential for using high hydrostatic pressure (HHP) to promote disintegration of the granule structure. The CLSM micrographs provided evidence of the substantial disintegration of granules due to HHP (600 MPa/5 min). Results from high performance liquid chromatography (HPLC) analysis indicated high concentrations of folate in the plasma fractions (230 µg/g dry matter) separated from the HHP-treated granule. Sodium Dodecyl Sulphate-Polyacrylamide Gel Electrophoresis (SDS-PAGE) analysis revealed the localization of phosvitin in the plasma fraction, which correlated with higher folate concentrations. The results demonstrate that phosvitin and folate were stable under the HHP conditions applied in this study. These findings provide evidence of a putative interaction between phosvitin and folate, and offer an improved model for the structure of granule.