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, kappa-carrageenan (kappa-C), lambda-carrageenan (lambda-C), iota-carrageenan (iota-C), and their blends (kappa-C + lambda-C, kappa-C + iota-C, lambda-C + iota-C, and kappa-C + lambda-C + iota-C) were included as stabilizers of PCEs to investigate effects of such carrageenans on their static stability. The results indicated that in comparison with lambda-C and iota-C, kappa-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 kappa-C + lambda-C, lambda-C + iota-C, and kappa-C + lambda-C + iota-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 kappa-C, kappa-C + lambda-C, lambda-C + iota-C, and kappa-C + lambda-C + iota-C exhibited low levels of watering-off (10.03-11.35% of creaming index) and agglomeration (676.00-1012.50 mPa & sdot;s of viscosity).