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Assemblages microniques de protéines sériques produits par étuvage à pH 9,5 : mécanisme de formation et propriétés physico-chimiques et fonctionnelles

Abstract : The dry heating of whey protein powder increases the functional properties of proteins such as their ability to form gels, foams or emulsions. The aim of this PhD thesis was to study the mechanism of formation and the physicochemical and rheological properties of protein assemblies of micrometer sizes that were produced by dry heating at 100 °C a whey protein powder isolate adjusted at pH 9.5 at a water activity of 0.2. Thus, morphological properties, protein denaturation, lactose conjugation and products of the Maillard reaction were studied during the time course of the dry heating. The role of each compound of the powder has also been studied by modification of the powder composition. Dry heating at pH 9.5 was able to form large assemblies of size and shape related to the size of the dry heated powder particles.In the first step, the glycation of proteins increased. Soluble aggregates formed and the powder browning progressed, while advanced glycated end products of the Maillard reaction were found. Then, the content in soluble aggregates decreased and large protein assemblies of micrometer sizes formed. These large assemblies were highly hydrated, and had very high viscosity values. Addition of lactose to the whey protein isolate powder allowed increasing the speed of formation of these large assemblies, increasing their density, and reaching higher yields of production. Caseins were able to join to whey proteins in the large assemblies, and had very poor effects on their structural properties and ability to retain the aqueous phase.
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  • HAL Id : tel-02009721, version 2
  • PRODINRA : 423830

Citation

Elise Schong. Assemblages microniques de protéines sériques produits par étuvage à pH 9,5 : mécanisme de formation et propriétés physico-chimiques et fonctionnelles. Ingénierie des aliments. Agrocampus Ouest, 2017. Français. ⟨NNT : 2017NSARB302⟩. ⟨tel-02009721v2⟩

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