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

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.