Compositional analysis and rheological characterization of gum tragacanth exudates from six species of Iranian Astragalus

The sugar composition and viscoelastic behaviour of Iranian gum tragacanth exuded by six species of Astragalus was investigated at a concentration of 1.3% and varying ionic strength using a controlled shear-rate rheometer. Compositional analysis of the six species of gum tragacanth by high-performance anion-exchange chromatography with pulsed amperometric detection suggested the occurrence of arabinose, xylose, glucose, galactose, fucose, rhamnose and galacturonic acid residues in the gum structure; however, the proportions of each sugar varied significantly among the gums from the different species of Astragalus, and this variation led to interesting differences in functional properties. Rheological measurements performed on dispersions of the six species of gum tragacanth demonstrated viscoelastic properties. The mechanical spectra derived from strain sweep and frequency sweep measurements indicated that the different gum tragacanth dispersions had distinctive viscoelastic behaviours. Investigation of the viscoelastic properties of the different gum dispersions in the presence of NaCl revealed that the addition of NaCl could lead to slight to drastic decreases in the G′, G″ or η^∗ values of the various gums. In general, the results indicated that the six varieties of gum tragacanth studied exhibited significantly different rheological properties; therefore, these different gums may find use in a variety of applications as stabilisers, thickeners, emulsifiers and suspending agents depending on their rheological behaviour.     

Zero‐Trans Cake Shortening: Formulation and Characterization of Physicochemical,Rheological, and Textural Properties

Cake shortening is an important ingredient that imparts taste and texture in the cake as the final product. Hydrogenated shortenings contain high amounts of trans fatty acids, which is considered a risk factor for obesity, cancers, and cardiovascular diseases. In this research, chemically interesterified blends of canola oil (CO) and palm stearin (PS) were recruited in order to formulate zero‐trans shortening, specifically for cake application. The optimization of shortening formulation was performed by Design‐Expert software, considering melting, congelation, textural, and rheological properties of cake shortening as responses. The formulated shortening in the weight ratio of 66.41:33.58 (PS:CO) (%, w/w) was analyzed and compared with two commercial cake shortenings in terms of fatty acid and triacylglycerol composition, slip melting point (SMP), solid fat content (SFC), and rheological and textural properties. The results showed that the formulated zero‐trans cake shortening with 0.2% trans, 47.2% saturated fatty acids, SMP of 40.9 °C, SFC of 10.51% at 37 °C, firmness of 1522.5 g, and linear viscoelastic range of 0.035% had the most acceptable criteria among cake‐shortening samples. The findings of this study offer insights into the relationship between shortening functionality and physicochemical properties and serve as a base for future studies on zero‐trans shortenings formulation.     

Physicochemical characteristics of beverage emulsions containing crocetin as a functional ingredient of saffron

Food Science and Biotechnology - This study aimed to investigate the physicochemical properties of beverage emulsions containing crocetin as a functional ingredient. The effect of different...     

Modeling the Rheological Behavior of Chemically Interesterified Blends of Palm Stearin/Canola Oil as a Function of Physicochemical Properties

The main aim of the current study was to model the rheological and textural properties of chemically interesterified palm stearin (PS)/canola oil (CO) blends as a function of saturated fatty acids (SFA), solid fat content (SFC), and temperature. The results and proposed models in this study can be used in design and development of new fat products by trying to limit the need for instrumental methods. To describe and predict how the viscoelastic properties and firmness of the blends change with SFA content, several models have been proposed. The firmness curves of fat samples were described as a function of (SFA, Firmness _f(SFA), Rsqr = 0.94, and mean absolute error (MAE) = 1009.00 g) and (SFC₂₀, Firmness _f(SFC20), Rsqr = 0.98, and MAE = 750.80 g) using a one-variable Quadratic model. In the next step, a two-variable Quadratic function for expression of firmness as a function of both SFA content and SFC₂₀ with high goodness of fit and low error (Rsqr = 1.00 and MAE = 0.00) was developed. The G′ modulus as a function of temperature (G′ _f(T)) and SFC (G' _f(SFC)) curves was S-shaped and the three Sigmoidal functions (Logistic, Gompertz, and Sigmoid models) were well able to describe their properties. However, the Logistic models described the G′ _f(T) (Rsqr>0.99 and MAE < 7838.00 Pa) and G′ _f(SFC) (Rsqr>0.94 and MAE < 20,802.00 Pa) curves in the best way. Finally, a two-variable Logistic model considering both temperature and SFC as variables was developed and fitted on the experimental data with Rsqr of 0.97 and MAE of 85,367.56 Pa. The validation of the proposed models shows their efficiency and ability for prediction of rheological and textural values of various interestrified blends.     

Ethyl cellulose/hydroxypropyl methyl cellulose-based oleogel shortening: Effect on batter rheology and physical properties of sponge cake

This study attempts to fill the gap in ongoing research on the design, optimization, and characterization of ethyl cellulose/hydroxypropyl methyl cellulose-based (EC/HPMC-based) low-saturated oleogel-shortenings by examining their functional effects on physicochemical, and rheological properties in the cupcake and its batter. Thus, the commercial shortening was completely replaced with the oleogel-shortenings in the cake formulation and, then, characteristics of the batter (including specific gravity, emulsion stability, and rheological properties), and cake samples (specific volume, moisture content, and texture properties) were evaluated and compared with each other and the control samples (containing commercial-shortening). In short, the EC-based- and EC/HPMC-based-oleogel-shortenings-batters had more specific gravity and emulsion stability than the control-batter. Liner viscoelastic rang in EC/HPMC-based-oleogel-shortenings-batter, EC-based-oleogel-shortenings-batter, and control-batter was 0.212%, 0.159%, and 0.195%, respectively. EC/HPMC-based-oleogel-shortenings-batter had a more viscoelastic behavior than EC-based-oleogel-shortening-batter after the control-batter (p < 0.05). The results of frequency sweep and dynamic shear tests indicated a higher similarity of the rheological behavior of the EC/HPMC-based-oleogel-shortening-batter with the control-batter. The results of moisture content and texture profile analysis of the cake samples indicated a slower staling in the oleogel-shortenings containing samples, especially EC/HPMC-based-oleogel-shortening type.