Time-Independent and Time-Dependent Rheological Characterization of Dispersions with Varying Contents of Chickpea Flour and Gum Arabic Employing the Multiple Loop Experiments.

The chickpea (Cicer arietinum) flour dispersions as the model system with different contents of flour (37% to 43%) and gum arabic (0% to 5%) were subjected to multiple loop experiments for simultaneous determination of the time-independent and time-dependent rheological characteristics. The Herschel-Bulkley model was suitable (0.993 ≤ r ≤ 0.999) to relate the time-independent characteristics linking shear stress and shear rate data for the individual upward and downward curves. The yield stress, consistency index, and apparent viscosity increased with the increasing flour and/or gum contents while flow behavior index (n) decreased. The yield stress generally decreased with the number of loops but n increased. In the individual loop tests, the n values for the decreasing shear stress/shear rate curves were always higher than corresponding increasing curves meaning a shift toward Newtonian characteristics. The time-independent properties (yield stress, apparent viscosity, consistency index, and n), the time-dependent characteristics like the area of the loop, and liquid characteristics like pourability and the nonoral sensory attributes (viscosity, spreadability, and tackiness) were individually predicted by artificial neural networks wherein the root mean square errors were between 3.6% and 17.2%. The sensory assessment indicated that the desirable parameters for a free-flowing and easily pourable spherical chickpea batter droplets occurred when the average pourability and spreadability values were 6.9 and 5.9, respectively. The normalized indices for these 2 parameters indicated that the batter having 40% flour and 2% gum contents was most suitable exhibiting a deviation of only 10% from the ideal sensory scores; these values were 40% and 0% to 3%, and 43% and 0%, respectively exhibiting up to 20% deviation.

J S ，Bhattacharya S 《-》

Rheology of Rice Flour Dough with Gum Arabic: Small and Large-Deformation Studies, Sensory Assessment and Modeling.

The absence of gluten protein makes the rice flour doughs difficult to handle when flattened/sheeted products are to be prepared. The rheological, sensory and microstructural changes in rice flour doughs having gum Arabic (0% to 5%, w/w) and moisture contents (44% to 50%) were studied for improving the dough handling characteristics. Rheological parameters like storage modulus (G') and complex viscosity (η*) decreased with an increase in moisture content while loss angle (δ) increased. A power-law type equation was suitable to relate angular frequency (ω) with G', G", and η* (0.814 ≤ r ≤ 0.999, P ≤ 0.01). An increase in gum and moisture contents increased δ from 6.9° to 15.5° but decreased the energy required for compression/flattening. The 6-element spring-dashpot model was suitable (r ≥ 0.991, P ≤ 0.01) for creep curves. The sensory panel had the opinion that dough with a low to moderate hardness between 3 and 4, and stickiness of ≤ 3.5 was suitable for the purpose of flattening in relation to the preparation of sheeted/flattened products; the appropriate condition for dough formulation was with the moisture and gum contents of 47.0% to 47.9% and 1.55% to 2.25%, respectively to offer the desirability index between 0.50 and 0.52. The microstructure of the rice flour dough in the absence of gum Arabic appeared to possess loosely bound flour particles. The presence of gum provided a coating on flour particles to yield dough having good cohesive microstructure.

Shanthilal J ，Bhattacharya S 《-》

Frying of the Dispersion Droplets with Varying Contents of Chickpea Flour and Gum Arabic: Product Characterization and Modeling.

Dispersions having chickpea (37%, 40%, and 43%, w/w) and gum arabic (0%, 1%, 2%, 3%, 4%, and 5%, w/w) solids were prepared. These dispersion droplets were fried, and the physical, sensory, and microstructural characteristics of the fried products were determined. The oil content in the fried snack decreased up to 20.3% when the level of chickpea and/or gum in the dispersions was increased. The compression curve for fried snack showed 5 major zones and exhibited the failure phenomenon. Failure force (6.5 to 11.4 N) increased with chickpea flour in the dispersions. Fracture strain (12.0% to 19.5%) indicated that all the fried samples were soft-crisp products. An increase in chickpea flour concentration offered an ovoid/oblong shape of dispersion droplets while falling to oil, and changed the spherical shape of the fried snack. The near-spherical product could be obtained by using 37% chickpea flour containing 0 to 2% of gum arabic, or with the 40% and 0 to 1% combinations. The hue or dominant wavelength increased from 578.5 nm (flour) to 581.0 to 582.7 nm (product) indicating a shift toward red coloration. A porous microstructure with scattered small cavities and large vacuoles of the fried snack were observed; big vacuoles were located in the inner portion of the fried product. The cells were divided into closed and open cells and were characterized by image analysis. The air cells usually had an elliptical shape with varying sizes; the cell wall thickness was between 12 and 80 μm. An artificial neural network (ANN) structure of 2-9-2 was developed for the prediction of sensory overall acceptability and oil content of the fried snack. Chickpea flour is used in several food preparations. The addition of gum arabic affects the textural and structural characteristics, and the sensory acceptance; the fried dispersion droplets have a lower fat content when gum arabic is used compared to samples fried without the addition of gum arabic. The fried dispersion droplets change their shape with the level of the ingredients used in the dispersion.

Shanthilal J ，Babylatha R ，Navya MC ，Chakkaravarthi A ，Bhattacharya S ... -  《-》

Gluten-free biscuits based on composite rice-chickpea flour and xanthan gum.

Benkadri S ，Salvador A ，Zidoune MN ，Sanz T ... -  《-》

Rheological and interfacial properties at the equilibrium of almond gum tree exudate (Prunus dulcis) in comparison with gum arabic.

Almond gum contains an arabinogalactan-type polysaccharide, which plays an important role in defining its interfacial and rheological properties. In this study, rheological and interfacial properties of almond gum and gum arabic aqueous dispersions were comparatively investigated. The interfacial tension of almond gum and gum arabic aqueous dispersions was measured using the pendant drop method in hexadecane. The asymptotic interfacial tension values for almond gum were significantly lower than the corresponding values measured for gum arabic, especially at high concentration. Rheological properties were characterized by steady and oscillatory tests using a coaxial geometry. Almond gum flow curves exhibited a shear thinning non-Newtonian behavior with a tendency to a Newtonian plateau at low shear rate, while gum arabic flow curves exhibited such behavior only at high shear rate. The influence of temperature (5-50  ℃) on the flow curves was studied at 4% (m/m) gum concentration and the Newtonian viscosities at infinite and at zero shear rate, for gum arabic and almond gum, respectively, were accurately fitted by an Arrhenius-type equation. The dynamic properties of the two gum dispersions were also studied. Both gum dispersions exhibited viscoelastic properties, with the viscous component being predominant in a wider range of concentrations for almond gum, while for gum arabic the elastic component being higher than the elastic one especially at higher concentrations.The rheological and interfacial tension properties of almond gum suggest that it may represent a possible substitute of gum arabic in different food applications.

Mahfoudhi N ，Sessa M ，Ferrari G ，Hamdi S ，Donsi F ... -  《-》