Combined Effects of Enzymatic Treatment and Spray Drying on the Functional Properties of Egg Yolk Main Fractions Granules and Plasma

Abstract

Changes in the techno-functional properties of hen's egg yolk main fractions, granules and plasma, were studied under various spray-drying conditions and enzymatic modification via phospholipase A₂ (PLA₂). The functional properties—for example gelling properties—of plasma fractions were maintained in a more or less native status if an enzymatic modification was done before spray drying. Furthermore, PLA₂ preprocessing significantly improved the surface activity of dried plasma fractions. Without enzymatic treatment, spray-dried plasma fractions showed an intense loss of surface activity and gelling properties due to a heat-induced denaturation and aggregation of plasma livetins and low-density lipoprotein (LDL) apoproteins. In contrast, high air outlet temperatures during spray drying resulted in a significant increase in the gelling ability of reconstituted granules. Additionally, PLA₂-modified granules showed considerably improved solubility and surface activity after spray drying compared to non-enzymatically modified granules.

Keywords:

• Egg yolk
• Granules
• Phospholipase A₂
• Plasma
• Spray drying

ACKNOWLEDGMENTS

The authors thank Cornelia Glashauser and Annette Brümmer-Rolf for their valued contribution in the experimental phase of this work. This research project was supported by the German Ministry of Economics and Technology (via AiF) and the FEI (Forschungskreis der Ernährungsindustrie e.V., Bonn), Project AiF 16009 N.