Static stability of partially crystalline emulsions stabilized by milk proteins: Effects of κ-carrageenan, λ-carrageenan, ι-carrageenan, and their blends

In addition to good whippability, partially crystallized emulsions (PCEs) represented by whipping creams and ice creams must also have prolonged long shelf-life. Carrageenan, the most commonly used thickener for production of PCEs, mainly comes in three commercial forms that may exert different effects on storage stability. In the present study, κ-carrageenan (κ-C), λ-carrageenan (λ-C), ι-carrageenan (ι-C), and their blends (κ-C + λ-C, κ-C + ι-C, λ-C + ι-C, and κ-C + λ-C + ι-C) were included as stabilizers of PCEs to investigate effects of such carrageenans on their static stability. The results indicated that in comparison with λ-C and ι-C, κ-C formed stronger three-dimensional networks with casein micelles, and effectively inhibited droplet flocculation of PCEs by improving zeta potentials (−19.93 mV) and reducing contribution of hydrophobic interactions (0.34 mg/mL) and disulfide bonds (0.34 mg/mL). Interestingly, combination of different types of carrageenans (especially κ-C + λ-C, λ-C + ι-C, and κ-C + λ-C + ι-C) also enhanced the electronegativity (−19.73 to −21.43 mV) and reduced the hydrophobic interactions (0.44–0.53 mg/mL) and disulfide bonds (0.03–0.34 mg/mL), which contributed to preventing fat droplets from flocculation during storage. After a storage of 2 months, the emulsions formulated with κ-C, κ-C + λ-C, λ-C + ι-C, and κ-C + λ-C + ι-C exhibited low levels of watering-off (10.03–11.35% of creaming index) and agglomeration (676.00–1012.50 mPa·s of viscosity). [Display omitted] •λ-C and ι-C PCEs underwent fast agglomeration and watering-off during storage.•κ-C formed a strong network by interacting with casein micelles.•κ-C reduced hydrophobic interactions and disulfide bonds among proteins.•κ-C effectively inhibited droplet aggregation and improved stability of PCEs.•There were synergistic interactions between different types of carrageenans.