Influence of whey protein-xanthan gum stabilized emulsion on stability and in vitro digestibility of encapsulated astaxanthin

Abstract

The combination of proteins and polysaccharides has potential to act as good emulsifiers and stabilizers. The aim of this study was to evaluate the stability of the emulsion system stabilized by whey protein isolate (WPI) (2-5 wt%) and xanthan gum (XG) (0.25 and 0.5 wt%). Furthermore, the influence of WPI-XG emulsion system on the thermal stability of 27 incorporated astaxanthin under different storage temperatures (5, 25, 37, 55 and 70 ºC) and in vitro digestion were investigated. The emulsion system with higher XG concentration (0.5 wt%) exhibited the highest viscosity, emulsion stability, and creaming stability. The 30 WPI-XG stabilized emulsion exhibited higher stability of astaxanthin at lower storage 31 temperature (5, 25 and 37 ºC) with 10-12% astaxanthin loss during 15 days of storage. During in vitro digestion, emulsion stabilized by WPI-XG demonstrated influence on 33 droplet digestion process, significantly (p˂0.05) lower lipid digestibility and lower 34 astaxanthin digestion (12.6%) in comparison to emulsion stabilized by WPI alone. This 35 research study provides platform for designing fortified food or beverage systems 36 incorporated with hydrophobic bioactive compounds for better stability and delivery to 37 target sites.