Water droplets as fillers: the effect of a dispersed aqueous phase on the rheology and microstructure of fat crystal-stabilized water-in-oil emulsions
Notice bibliographique
Résumé
Composite systems are continuous matrices that contain embedded particles, called fillers, that can be used to manipulate the mechanical strength and viscoelastic properties of the resulting material. The use of fillers in composite systems is common practice and largely depends on particle size and shape, surface functional groups and aggregation behaviour. Emulsions are complex food dispersions and, while they have structural similarities in common with composites, they are not widely considered in this light. In this thesis, fat crystal network-stabilized emulsions prepared using various emulsifiers were studied to determine whether varying the structure of the water droplet surface could modulate the viscoelastic behaviour of the resulting composite. The oil phase consisted of a high melting triglyceride in canola oil with an emulsifier that promoted a specific droplet surface, namely polyglycerol polyricinoleate (PGPR) which did not promote interfacial crystallization, or one of two monoglycerides [glycerol monooleate (GMO), or glycerol monostearate (GMS)], which both enhanced interfacial crystallization of fats. Interfacial fat crystallization imparted structural rigidity by surrounding the dispersed aqueous droplets within a solid shell that interacted with adjacent network crystal aggregates and other droplets. The work here shows that the presence of interfacial fat causes the droplet to promote an increase in viscosity and in G′, thus reinforcing the crystal network. These effects were enhanced by decreasing the droplet size and increasing the volume fraction of the dispersed aqueous phase. As well, the crystalline shell that provided imparted active filler qualities to the droplets also protected the droplet from shear degradation, protecting encapsulated contents from being released. PGPR, a branched, polymeric emulsifier, minimized the presence of interfacial fat crystallization such that interactions of the dispersed droplets interacted only weakly with nearby droplets and fat crystals. As a result, the dispersed phase did not have a pronounced effect on emulsion reinforcement or viscosity and displayed predominantly viscous behaviour irrespective of volume fraction. These aqueous droplets were also less effective as encapsulation vehicles as they were more prone to shear-mediated release of encapsulated material. These results show that the droplet interface is determinant in fat crystal network rheology and shear-stability by establishing the dispersed phase droplets of such emulsions as either active or inactive fillers. Mechanically strong droplets (i.e., those with interfacial fat crystal shells) which interacted strongly with their surroundings more effectively reinforced/added rigidity to the emulsion - behaviour typical of active fillers. Conversely, the presence of weakly interacting droplets (i.e., liquid interface) did not impart changes to emulsion rheology. As with solid filler particles, droplet characteristics, such as size and volume fraction can then be used to predictably modulate viscoelastic behaviour and encapsulation efficiency. Filler “activity” can also be used as a tool to control encapsulation or release of compounds during shear. This thesis experimentally demonstrates that embedded droplets with interfaces tailored by the use of surfactants can be considered a functional and tunable component of fat crystal network-stabilized emulsions.
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,001 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».