Extensional and shear rheology of okra polysaccharides in the presence of artificial saliva

Extensional and shear viscosities were studied for mixtures comprising artificial saliva and okra mucilage, the latter acting as a model thick-liquid food. These experiments aimed to obtain information on the flow-behavior information of the systems, underpinning the texture sensation of foods as perceived by dysphagic and xerostomic populations. Mixing okra mucilage with artificial saliva dramatically increases the shear viscosity of artificial saliva throughout the studied ranges of concentrations and deformation rates. Particle tracking does not suggest direct interactions between the components of artificial saliva and of okra mucilage. The rheology of the okra polymer (OP)–artificial saliva (AS) mixture is dominated by its extensional viscosity: Trouton ratios are in the order of tens to hundreds, while they decrease with increasing okra-mucilage concentration; this highlighs the dominance of the extensional rheology and the increasing importance of the shear mechanics with increasing okra content. The relaxation times and extensional moduli are also reported for the systems under study. Extensional and shear flows are of equal importance concerning the elastic behavior

Thermodynamics of a food macromolecular assembly: the case of okra mucilage

Isolation steps of okra hydrocolloid and its thermodynamic parameters.</p

Effect of barley β-glucan concentration on the microstructural and mechanical behaviour of acid-set sodium caseinate gels

The microstructural and mechanical properties of acid-set mixtures of sodium caseinate (2% w/w)/barley β-glucans (2–6% w/w) were studied in an effort to evaluate the effect of these polysaccharides on the texture of fermented dairy products. The phase behavior of the blends was investigated using small deformation dynamic oscillation, differential scanning calorimetry, optical microscopy, and polymer blending-laws analysis. The work aimed to assess the topology of the phase separated mixture, the water holding capacity of its polymeric phases, and the thermal stability of the constituent networks. The mixed network properties were dominated by the protein component at low concentrations of β-glucans (≤3% w/w). In the concentrated regime, the system seems to have a bicontinuous topology governed by the mechanical strength and thermal stability of the β-glucan network structure. Results could assist in optimising the use of sodium caseinate and β-glucans as functional or as bioactive ingredients in acid-set dairy product

Emulsifiers from White Beans: Extraction and Characterization

This paper studies the emulsification capacity of aqueous extracts from white beans and reports the relations between the composition and structure of the extracts’ macromolecular components and their exerted emulsification ability. The extracts comprise of three distinct populations: one of large (few MDa) polysaccharides, proteins (tens of kDa), and smaller molecular entities (oligopeptides and oligosaccharides, polyphenols, and salts, among other molecules); the proteins and the smaller molecules adsorb onto oil–water interfaces, providing some emulsification capacity at pH 3 and adequate emulsification at pH 7. Unabsorbed polysaccharides, such as starch, cause depletion flocculation. Pickering phenomena are involved in the stabilization mechanism. The findings are supported by SEC–MALLS/UV, confocal microscopy, zeta potential measurements, and FT–IR data. A discussion is made on the particular attributes of each population in emulsion stability, on their relevance to culinary practice, and in their potential as replacers of artificial emulsifiers

Physicochemical aspects of mucosa surface

An insight into adsorption thermodynamics of molecular probes onto the mucin surface of porcine intestinal is given by the aid of IGC based on chromatographic retention time.</p