Application of whey protein-guar gum binary emulsion gels as fat replacer and delivery system for vitamin D₃ in low-fat yogurt

A binary cross-linked emulsion gel delivery system using whey protein (WP) and guar gum (GG), was developed as fat replacer and carrier for vitamin D 3 in low fat yogurt. The emulsion gels were incorporated into skim milk at a substitution level of 10% (w/w) for the production of low-fat yogurt. Yogurts containing emulsion gels showed 33.42% increase in water-holding capacity and significantly higher hardness and cohesiveness compared with low fat yogurt. Encapsulation improved vitamin D₃ retention from 46.56% in non-fat yogurt to 68.38% in SWP-GG emulsion gel after 21 days of storage. In simulated digestion, the sonicated whey protein-guar gum emulsion gel delayed gastric release (13.7% in SGF) and enhanced intestinal release (35.5% in SIF) of vitamin D 3 , leading to a 1.5-fold increase in bioaccessibility compared with control sample. Kinetic modeling revealed that vitamin D₃ release from yogurt containing emulsion gels indicated a controlled release, governed by diffusion and matrix erosion. Sensory evaluation confirmed higher scores for creaminess, consistency, and overall acceptability, without undesirable flavors. These findings indicate that the binary whey protein-guar gum emulsion gels are effective carriers for vitamin D₃ fortification while improving the sensory and textural quality of non-fat yogurt.