Effect of temperature on whey protein isolated (WPI) films adsorbed at the water-oil interface

Authors

  • Mª Rosario Rodríguez Niño Departamento de Ingeniería Química. Facultad de Química. Universidad de Sevilla
  • Cecilio Carrera Sánchez Departamento de Ingeniería Química. Facultad de Química. Universidad de Sevilla
  • Juan M. Rodríguez Patino Departamento de Ingeniería Química. Facultad de Química. Universidad de Sevilla

DOI:

https://doi.org/10.3989/gya.2002.v53.i3.327

Keywords:

Interfacial gelation, Protein, Water-oil interface, Interfacial rheology, Whey protein isolate, Food emulsifier

Abstract


Heat-induced interfacial aggregation of a whey protein isolate (WPI) with a high content of β-lactoglobulin, previously adsorbed at the oil-water interface, was studied by interfacial dynamic characteristics (interfacial tension and surface dilational properties) performed in a automatic drop tensiometer coupled with microscopic observation and image analysis of the drop after heat-treatment. The temperature, ranging between 20 and 80 ºC, and protein concentration in aqueous bulk phase, ranging between 1.10-1 and 1.10-5% wt/wt, were studied as variables. The pH, and ionic strength were maintained constant at 5 and 0.05 M, respectively. During the heat-treatment, WPI films behave typically as viscoelastic with non-zero phase angle, but with increasing elastic characteristics as the heat-treatment progresses. During isothermal treatment the surface dilational modulus, E, increases and the interfacial tension, σ, and phase angle, φ, decrease with time to a plateau value. The time dependence of E can be quantified by a first-order equation according to two kinetic mechanisms. The rate of thermal changes in WPI adsorbed films increases with protein concentration in solution. Heat-treatment produces irreversible changes in WPI adsorbed films because the interfacial characteristics do not return to original values after cooling back to the initial temperature. Significant changes in interfacial characteristics and drop image associated with interfacial WPI gelation were observed at protein concentration as low as 1.10-5% wt/wt, even for heat-treatment at 40 ºC.

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Published

2002-09-30

How to Cite

1.
Rodríguez Niño MR, Carrera Sánchez C, Rodríguez Patino JM. Effect of temperature on whey protein isolated (WPI) films adsorbed at the water-oil interface. grasasaceites [Internet]. 2002Sep.30 [cited 2022Dec.7];53(3):340-51. Available from: https://grasasyaceites.revistas.csic.es/index.php/grasasyaceites/article/view/327

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Research