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Communication Dans Un Congrès Année : 2019

Kinetics of heat-induced denaturation of whey proteins and characterization of protein aggregates in model infant formulas

Résumé

In 2018, about 60% of world’s newborns received cow milk-based infant formulas (IF) instead of human milk (UNICEF). The process of manufacturing IF involves heat treatments altering the physicochemical properties of milk components, especially whey proteins (WP), and so the rheological properties of IF. The objective of the study was to investigate the impacts of thermal treatments on the denaturation of WP of IF, particularly for those mimicking the protein profile of human milk, and to characterize the heat-induced protein structures. Three model IF were produced with a caseins:WP ratio of 40:60 at 1.3% and 5.5% of total proteins, i.e. the protein contents at which are applied heat treatments during the manufacture of liquid or powder IF, respectively. Skimmed milk was mixed with a WP isolate, a mix of WP isolate and purified lactoferrin or a mix of both purified lactoferrin and α-lactalbumin in proportion similar to that in human milk. The kinetic of heat-induced denaturation of each WP was investigated between 67.5°C and 80°C by RP-HPLC. The heat-induced protein structures were studied by dynamic light scattering, electrophoresis and asymmetric flow field flow fractionation coupled with MALLS. The results revealed that the extent of denaturation of WP depended on the protein content and the nature of the WP within the IF. IF at 5.5% of proteins and containing β-lactoglobulin gelled for longer heating time at 80°C. At similar rate of total WP denaturation at 67.5°C and 80°C, the protein composition of the heat-induced aggregates changed between formulas, protein concentrations and heating temperatures but disulfide bonds were the main intermolecular links. The aggregates were larger and of fractal shape (dfapp=2.1) in formulas at 5.5% proteins whereas they were of spherical shape (dfapp=2.9) in formulas at 1.3% proteins. These results will give to industrials reliable data on the protein structures formed during the heat treatments of IF. The impact on digestibility will be subsequently investigated.
Présentation - ISFRS - Amira - Juin 2019.pdf (3.26 Mo) Télécharger le fichier
Format : Présentation

Dates et versions

hal-02164163 , version 1 (24-06-2019)

Identifiants

  • HAL Id : hal-02164163 , version 1
  • PRODINRA : 475143

Citer

Amira Halabi, Amélie Deglaire, Marie Hennetier, Frédéric Violleau, Said Bouhallab, et al.. Kinetics of heat-induced denaturation of whey proteins and characterization of protein aggregates in model infant formulas. 8. ISFRS 2019, International Symposium on Food Rheology and Structure, Jun 2019, Zurich, Switzerland. ⟨hal-02164163⟩
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