Publications by authors named "Derick Rousseau"

Emulsifiers play an essential role in the flow behaviour of confectionery products such as chocolate. This research associated emulsifier adsorption onto sugar crystals and its effects on the flow properties of model sugar-in-oil suspensions. A new method to quantify emulsifier adsorption onto sugar crystals dispersed in oil was developed by exploiting the relationship between oil-water interfacial tension and unadsorbed emulsifier in the continuous oil phase.

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The controllable formation of anisotropic gel structures is presently sought for the development of foods with novel textures. Here, we used unidirectional freezing to generate agar gels consisting of a honeycomb-like porous network of elongated and aligned pores. A custom-built Peltier system allowed for control of the freezing front velocity throughout the agar gels.

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There is continuing interest in finding new approaches to gel liquid oil for processed food applications. Here, we combined oleogels and capillary suspensions to generate model oil-continuous networks consisting of a wax oleogel and a water-bridged, glass particle network. The composition map tested comprised 30 vol% polar or non-polar glass beads dispersed in a 70 vol% non-particle phase consisting of water (≤9 vol%) as well as 2 wt% hexatriacontane as oleogelator in canola oil.

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Hypothesis: Colloidal particles can be used to generate water-in-oil (W/O) emulsions resistant against coalescence. Demulsification is possible with addition of low molecular weight surfactants to the emulsion continuous oil phase. Whether surfactants demulsify particle-stabilized W/O emulsions depends on their ability to modify the wettability of interfacially-bound particles.

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Hypotheses: Monoolein liquid crystals find use in foods and pharmaceuticals. Our hypotheses were: (a) liquid crystal symmetry dominates yielding and large deformation, and (b) strain rate frequency superposition (SRFS) may be used to determine mesophase long and short relaxation times.

Experiments: Liquid crystal microstructure and rheology were characterised as a function of temperature and composition.

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A rising health concern with saturated fatty acids allowed researchers to look into the science of replacing these fats with unsaturated fatty acids. Oleogelation is a technique to structure edible oil using gelators. The present study looked for the effect of solid emulsifiers; namely, sorbitan monostearate (SP) and stearyl alcohol (SA), on the physicochemical parameters of oleogels.

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The effects of up to 5 wt% rice bran wax (RBX) on the crystallisation, tempering and storage stability of cocoa butter (CB) and a model dark chocolate were assessed. Presence of RBX significantly accelerated tempering and the formation of the desirable form V polymorph in CB. The form V to VI transition in both CB and chocolate was slowed in the presence of RBX during temperature-cycling, with addition of 1 wt% wax effectively reducing the extent of bloom formation in model chocolate following two weeks of temperature-cycling from 25 to 29 °C.

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Surfactants are used in confectionery production to control the viscosity and yield value of molten chocolate. To develop a deeper understanding of the structure-function relationship of surfactants in food-related particle suspensions, the apparent viscosity, yield value, sedimentation, and particle interactions of 10 wt% confectioner's sugar-in-canola oil suspensions were investigated in the presence of up to 1 wt% commercial soy lecithin, polyglycerol polyricinoleate (PGPR), citric acid esters of monoacylglycerols (CITREM) or ammonium phosphatides (AMP). Atomic force microscopy (AFM) was used to measure attractive forces at the nano-Newton scale between a sugar substrate and a sugar crystal-functionalized AFM cantilever in an oil environment.

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Matching the texture of fat in plant-based meat alternatives requires an in-depth understanding of the rheology of animal adipose tissue which, to-date, remains under-studied. Here, we characterised the small and large deformation behaviour of back fat from pork, beef, and lamb, with the underlying goal being the establishment of the temperature-dependent structure-function relationship governing the texture and rheology of adipose tissue. The dynamic rheological behaviour of the back fats was characterised frequency and amplitude sweeps and large amplitude oscillatory strain (LAOS), as well as texture analysis puncture tests.

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We investigated the temperature-dependent microstructure and thermal properties of back fat adipose tissue from pork, beef and lamb. Microstructural characterisation electron, confocal and light microscopy showed that the back fats were structurally similar and consisted of fat dispersed as discrete units within a protein matrix akin to a closed cell foam. Differential scanning calorimetry showed distinct fat melting profiles for each of the tissues, which were ascribed to differences in fatty acid profile.

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The effects of 2 wt% emulsifier and crystalline sugar on the isothermal solidification and polymorphic behavior of cocoa butter were evaluated. The emulsifiers investigated were commercial soy lecithin, polyglycerol polyricinoleate (PGPR), citric acid esters of mono- and diacylglycerols (CITREM) and ammonium phosphatides (AP). All emulsifiers accelerated cocoa butter nucleation and growth from the melt, with PGPR showing the smallest enhancement.

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All foods harbor unique length scale-dependent structural features that can influence the release, transport, and utilization of macro- or micronutrients in the human gastrointestinal tract. In this regard, food destructuring and restructuring processes during gastric passage significantly influence downstream nutrient assimilation and feelings of satiety. This review begins with a synopsis of the effects of oral processing on food structure.

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Dietary protein affects energy balance by decreasing food intake (FI) and increasing energy expenditure through diet-induced thermogenesis (DIT) in adults. Our objective was to investigate the effects of increasing the dietary protein in an isocaloric breakfast on subjective appetite, FI, blood glucose, and DIT in 9-14 y children. Two randomized repeated measures designs were used.

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The objective of this study was to determine the effect of white potato cooking methods on subjective appetite, short-term food intake (FI), and glycemic response in healthy older adults. Using a within-subject, repeated-measures design, 20 participants (age: 70.4 ± 0.

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Hypothesis: Micron and nano-scale particles are increasingly used to stabilize water-in-oil (W/O) emulsions. Though remarkably stable, the resulting emulsions can be broken by adding low molecular weight surfactants that modify the wettability of the interfacially-adsorbed particles.

Experiments: W/O emulsions were prepared using lipophilic crystals of the monoglyceride glycerol monostearate (GMS), followed by addition of sorbitan monooleate (SMO) at concentrations below and above its critical micelle concentration (CMC).

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Solid lipid nanoparticles (SLNs) containing up to 37.5 wt % all-trans β-carotene in the lipid phase are potential water-dispersible food colorants. SLNs have been made by hot-melt high-pressure homogenization with fully hydrogenated sunflower oil and with polysorbate 80 and sunflower lecithin as stabilizers.

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We use coarse-grained molecular dynamics simulations to study the effect of surfactant structure on the ordering of bulk tristearin at an oil-water interface. In the absence of surfactant, tristearin acyl chains are marginally aligned normal to the interface. The surfactant glycerol monooleate (GMO), a common small-molecule monoacylglycerol (MW: 357 g/mol), preferentially adsorbs to the oil-water interface, displacing more of the tristearin as its concentration increases.

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Oleogelation is shown to delay the in vitro digestion of soybean oil (SBO) dispersed within an oil-in-water (O/W) emulsion. Rice bran wax (RBX) was used as an oleogelator at concentrations of 0, 0.25, 0.

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The relationship between microscopic and macroscopic properties in fat-continuous dispersions is multifaceted compared to bulk oils, which limits the ability to extrapolate results from bulk systems towards complex formulations. The impact of confectioner's sugar on the crystallization and rheology of palm oil (PO) and mid-fraction blend (PMF) was investigated in this study. Adding sugar significantly increased storage modulus (G') and firmness (F) of the oils while exhibiting increased sensitivity towards processing conditions.

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Structural and rheological properties of oleogels consisting of 0.5-25 wt% rice bran wax (RBX) in rice bran oil (RBO) were explored. RBX was an efficient, thermoreversible oleogelator capable of structuring RBO at concentrations as low as 0.

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The influence of emulsifier physical state and concentration on the in vitro digestion of oil-in-water (O/W) emulsions was investigated. Two citrated monoacylglycerols, glyceryl stearate citrate (GSC, bulk mp of 55-65 °C) and glyceryl oleate citrate (GOC, bulk mp of 0-10 °C), were used at 0.5 or 5 wt % of the emulsions to generate 20 wt % soybean oil O/W emulsions.

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: Dietary pattern changes, as a part of a healthy lifestyle, may improve weight management. The objective of this study was to examine the effect of midmorning puree snacks varying in macronutrient composition and energy content on subjective appetite, food intake, and glycemic and insulin responses in healthy adults.: In a randomized, repeated measures crossover design, 6 treatments (snack skipping and purees: control [186 kcal], maltodextrin [272 kcal], whey protein [201 kcal], oat [276 kcal], and coconut oil [276 kcal]) were administered to 23 normal weight adults (n = 14 males, n = 9 females).

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The effect of sugar-sweetened beverages (SSBs) on satiety and short-term food intake (FI) regulation in girls has received little attention. The objective of the present study was to compare the effect of pre-meal consumption of commercially available SSBs on subjective appetite and short-term FI in 9-14-year-old girls. The methods we used include using a randomized crossover design in which 28 girls consumed isovolumetric amounts (350 mL) of a fruit drink (154 kcal), cola (158 kcal), 1% chocolate milk (224 kcal), or water (control; 0 kcal) on four separate mornings.

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Pickering emulsions are colloidal dispersions stabilized by particles that either migrate to, or are formed at, the oil-water interface during emulsification. Here, we fabricated and characterized Pickering water-in-oil emulsions where molten glycerol monostearate crystallized at the surface of micron-sized water droplets and formed protective solid shells. We tested this emulsion as a reservoir delivery platform for the sustained release of low molecular weight hydrophilic molecules including sodium chloride (NaCl) and sodium citrate as model compounds, and the therapeutic oseltamivir phosphate (OP), the delivery of which was the ultimate goal of this research.

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Dietary fats and oils are an important component of our diet and a significant contributor to total energy and intake of lipophilic nutrients and bioactives. We discuss their fate in a wide variety of engineered, processed and naturally-occurring foods as they pass through the gastrointestinal tract and the implicit role of the food matrix within which they reside. Important factors that control fat and oil digestion include: 1) Their physical state (liquid or solid); 2) Dispersion of oil as emulsion droplets and control of the interfacial structure of emulsified oils; 3) The structure and rheology of the food matrix surrounding dispersed oil droplets; and 4) Alteration of emulsified oil droplet size and concentration.

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