Formation by high power ultrasound of aggregated emulsions stabilised with milk protein concentrate (MPC70)

Ultrasonics Sonochemistry

Muthupandian Ashokkumar¹  Yacine Hemar²  Lan Luo³  Ruijia Zhang³  Zhi Yang³ 

[1] Corresponding authors.;School of Chemistry, The University of Melbourne, Parkville, Victoria 3010, Australia;School of Food and Advanced Technology, Massey University, Auckland 0632, New Zealand;

关键词: Emulsions;    Milk protein concentrates;    Microstructure;    Viscosity;    Oil droplets aggregation;   

DOI  :  

来源: DOAJ

【 摘 要 】

In this work, oil-in-water emulsions stabilised by milk protein concentrate (MPC70) were investigated. The MPC70 concentration was kept constant at 5% (close to the protein content found in skim milk) and the oil volume fraction was varied from 20 to 65%. Sonication was performed at 20 kHz and at a constant power of 14.4 W for a total emulsion volume of 10 mL. Under certain oil concentration (≥35%) and sonication times (≥3s) the emulsion aggregated and formed high-viscosity pseudo plastic materials. However, the viscosity behaviour of the emulsion made with 35% oil reverted to that of a liquid if sonicated for longer times (≥15 s). Confocal laser scanning microscopy showed clearly that the oil droplets are aggregated under the sonication conditions and oil concentrations indicated above. An attempt to explain this behaviour through a simple model based on the bridging of oil droplets by the MPC70 particles and, taking into account the oil droplet and MPC70 particle sizes as well as the oil volume fraction, was made. The model fails to describe in details the aggregation behaviour of these emulsions, likely due to the inhomogeneous protein layer, where both free caseins and casein micelles are adsorbed, and to the packing of the oil droplets at concentrations ≤55%. Nonetheless, this work demonstrates the potential of ultrasound processing for the formation of dairy emulsions with tailored textures.

【 授权许可】

Unknown