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The incidence and prevalence of dysphagia worldwide are increasing yearly requiring a change in food texture to avoid malnutrition, dehydration, or sever complications. Riceberry porridges fortified with protein hydrolysate (1.5%), bio‐calcium (589 mg), and thickened with xanthan gum (XG) of varying concentrations (0%, 0.255, 0.50%, 0.75%, 1.0%, and 2.0%) showed suitability for use in enriching diets of these patients. Porridges were examined using specified tests from the International Dysphagia Diet Standardization Initiative (IDDSI) and National Dysphagia Diet (NDD), and coupled with rheological, textural analyses, in vitro swallowing simulator and sensory analysis performed by a trained panel. Porridges with 0%–0.25% and 0.50%–2.0% XG were classified as IDDSI level 3 and 4, respectively, and apparent viscosities of porridges showed samples with XG displayed shear thinning behavior beneficial for patients with dysphagia. Increasing XG concentrations increased the consistency coefficient and decreased the flow behavior index (p <.05) with positive correlation of XG concentration with textural properties including firmness, consistency, cohesiveness, adhesiveness, and stickiness values. The relationship between instrumental measurements, in vitro and in vivo swallowing behavior showed high correlations with regards to XG concentration (r =.995). The findings indicate Riceberry porridges containing XG have significantly improved textural properties over those without XG for patients with dysphagia. [ABSTRACT FROM AUTHOR]

It is necessary to find food additives that can reduce the food friction coefficient, in order to make it easier for the elderly and people with dysphagia to swallow. The sesame paste and rice paste are two typical foods eaten by the elderly. In this research, the tribological and rheological properties of 2 paste with 12 hydrocolloids were investigated. The results showed that three hydrocolloids (xanthan gum, gellan gum, and pectin) could reduce the friction coefficients of sesame paste and rice paste within a certain range of oral friction velocity. The friction coefficients of two kinds of original paste are in the order of 10−1. The addition of three hydrocolloids can reduce them to about 10−2, effectively improving lubrication. After adding hydrocolloids, the particles cross‐link to form a network structure, which improves the viscosity and lubrication of food to a certain extent. This has potential application value for designing food that is more conducive to swallowing. [ABSTRACT FROM AUTHOR]

Viscoelastic properties of 3D printable peanut‐based food ink were investigated using frequency sweep and relaxation test. The incorporation of xanthan gum (XG) improved the shear thinning behavior (n value ranging from 0.139 to 0.261) and lowered the η*, G′, and G′′ values, thus making food ink 3D printable. The addition of XG also caused a downward shift in the relaxation curve. This study evaluates the possibility of an artificial neural network (ANN) approach as a substitute for the Maxwell three‐element and Peleg model for predicting the viscoelastic behavior of food ink. The results revealed that all three models accurately predicted the decay forces. The inclusion of XG decreased the hardness and enhanced the cohesiveness, so enabling the 3D printing of food ink. The hardness was highly positively correlated with Maxwell model parameters Fe, F1, F2, F3, and Peleg constant k2 (0.57) and negatively correlated with k1 (−0.76). [ABSTRACT FROM AUTHOR]

The purpose of this study was to improve the method of using an inclined parallel plate (IPP) in directly estimating the yield stress τiy and evaluating the properties of a thickened liquid. The flow curve of the relationship between the shear rate and shear stress of a liquid thickened with a xanthan gum agent was predicted using the Herschel–Bulkley fluid model (τ=τy+kγ˙n−1). We supposed that the yield stress τy and the result of a line spread test (LST) indicate the deformation state and the flow state of shear stress (kγ˙n−1), respectively. τiy, the yield stress τry estimated adopting a rotational viscometer and LST, was investigated for three liquids thickened with xanthan gum at four concentrations (C) at intervals of 0.5 wt% within the range 0.5–2.0 wt%. Linear plots of the relations of C versus τiy and τry and the LST show that with an increase in C, the resistance force (τry and τiy) increases until flow starts, after which viscosity increases. We suggest that yield stress τiy estimated with the IPP method effectively indicates the rheological properties of thickened liquids. [ABSTRACT FROM AUTHOR]

The aim of the present study is to characterize the mechanical properties of O/W emulsion gels stabilized through soy protein isolate (SPI)‐xanthan gum (XG) complex and to elucidate their practical usefulness in plant‐based processed meat products. O/W emulsions prepared by mixing aqueous solutions of SPI‐XG complexes, which was formed via electrostatic interactions under acidic conditions (pH 4.0), with plant oil were gelled in the presence of several hydrocolloids. Effects of hydrocolloid composition, oil type and load, and oil droplet size on the mechanical properties of the emulsion gels were investigated by dynamic viscoelasticity measurements, and fluorescence microscopy was performed for observation of the oil droplet dispersion. Results indicated that methylcellulose should be required to provide the gels with heat resistance and that the type of oil used should affect dynamic storage modulus (G') of the gels particularly at lower temperatures. It was also found that increased oil load should decrease the gel's resistance to deformation, making the gel structure brittle, and that oil drop size should affect G' and dynamic loss modulus (G") at lower strains. Food application tests indicated that the emulsion gels used had a great impact on the mechanical properties of plant‐based meat patties. These findings would contribute to the utilization of the emulsion gels as a lipid portion in plant‐based processed meat products, leading to the progress of industrial practice. [ABSTRACT FROM AUTHOR]

Generally, the foods we usually eat are not only aqueous solutions, but also viscous solutions and solids. Therefore, it is interesting for us to explore how taste components are perceived in a viscous polymer solution. The relationship between the sensory evaluation of saltiness intensity, amount of added oil, and apparent viscosity was clarified in low‐viscosity and high‐viscosity polymer solutions. The study was conducted using samples containing corn oil, sodium chloride, and [xanthan gum] or [xanthan gum + locust bean gum] as a thickener. Oil was added to the viscous polymer solutions regardless of whether they were low‐ or high‐viscosity, and saltiness intensity was evaluated as compared with a reference solution. The low‐viscous polymer solutions with [xanthan gum] were perceived to be saltier than the high‐viscous polymer solutions with [xanthan gum + LBG] as the amount of oil increased. The shear stress value gradually increased as the amount of oil increased in both the low‐viscosity and the high‐viscosity polymer solutions, as derived from the fluid constitutive equation. There was a correlation between saltiness intensity and apparent viscosity in both high‐ and low‐viscosity polymer solutions. A coefficient of determination (R2) of 0.918 was obtained between saltiness intensity and "apparent viscosity" for the samples using [xanthan gum] and that of 0.683 between saltiness intensity and "apparent viscosity" for the samples using [xanthan gum+LBG]. The low‐viscosity polymer solutions showed a saltier intensity as the amount of oil increased and a greater correlation with apparent viscosity, as compared with the high‐viscosity polymer solutions. [ABSTRACT FROM AUTHOR]

The aim of this work was to examine relations between instrumental and sensory parameters in a texture modified food matrix, with and without saliva. Nine pureed carrot samples (eight thickened and a control) were developed with starch (0.4 and 0.8% wt/wt), xanthan (0.2 and 0.4% wt/wt) or starch–xanthan blends that met International Dysphagia Diet Standardisation Initiative (IDDSI) Level 4 guidelines using fork and spoon tests. Rheological and tribological tests were conducted on the food and simulated bolus prepared by adding fresh stimulated saliva to the food (1:5, saliva:food) to mimic oral processing. Perceived sensory properties were identified using a temporal dominance of sensations (TDS) test (n = 16) where panelists were given a list of nine attributes. The area under the curve was extracted from TDS curves for each attribute/sample and this was correlated with rheological (viscosity at 10 s−1, G′, G″, and tan δ at 1 Hz) and tribological (friction coefficient in three regimes) data. The viscosity of the control sample decreased after adding hydrocolloids (except Starch_0.8%) and with saliva incorporation. G′ and G″ either increased or were similar for xanthan and blends and decreased for starch‐thickened samples. Hydrocolloid addition increased friction for all samples and was higher with saliva addition. Sensory results showed that samples with starch were perceived as thick and grainy while xanthan was perceived as smooth and slippery. A greater number of sensory attributes correlated with viscoelastic parameters compared to friction coefficients. Correlations were highest with the saliva added samples, further highlighting the importance of including saliva during instrumental testing. [ABSTRACT FROM AUTHOR]

Viscosity measurement using a cone‐and‐plate rheometer is considered to provide an objective and reliable evaluation of thickening agents for dysphagia management. Here, we showed its measurement uncertainty in the context of an inter‐laboratory study. Eight test samples (i.e., four viscosity standard liquids, one xanthan gum reagent powder, and three commercial thickening agent powders) were distributed to 10 laboratories in a blinded manner. According to the same standard operating procedure, each laboratory dissolved the xanthan gum or thickening agents at four concentrations (0.5–4.0 g/100 g) and then measured their viscosity (35–803 mPa∙s). As for the viscosity of the standard liquids, the grand means were 98–100% of the certified values, and the relative standard deviations for repeatability (RSDr) and reproducibility (RSDR) were ca. 1% and ca. 5%, respectively, suggesting good accuracy in the measurement process. On the other hand, as for the viscosity of the thickening agents, RSDr and RSDR were ca. 2–6% and ca. 5–8%, respectively; however, heterogeneity in the preparation process comprising a manual dissolving step may increase these to near 60%. Furthermore, RSDr and RSDR of estimated additive concentrations to achieve targeted viscosities (50–500 mPa∙s) based on concentration‐viscosity curves were ca. 1–3% and ca. 3–5%, respectively, with a few exceptions. These findings suggest that a strictly standardized procedure provides reliable data on the viscosity measurements for thickening agents. [ABSTRACT FROM AUTHOR]

Managing the thickening index of food is important for dysphagia and helps in recognizing the static and dynamic rheological properties of the thickening agent. One dynamic property is the viscosity under a shear rate of 50 s−1, and one static property is the yield stress at a shear rate of 0 s−1. The purpose of this study is to design a simplified inclined plane test to identify the yield stress of a thickened liquid by observing flow behavior on an inclined plate. The yield angle (stress) is defined as the inclination angle of the plate just before the thickened liquid flows. The concentrations (yield stresses, yield angles) of a thickening agent containing xanthan gum are 1.0 (1.2, 3°), 1.5 (5.6, 13°), 2.0 (7.5, 26°), 2.5 (12.5, 26°), and 3.0 (19.1, 42°) wt% (Pa, degrees). We measured the time course of the displacement of the downstream edge (DDE) of the thickened liquid on the inclined plate. The discrete inclination angles were in the range of 0° to 42°. The DDE after 10 s was more than 4.5 mm for all concentrations of the thickening agent at an inclination greater than the yield angle of the plate. We confirmed that the yield angle identifies the yield stress for the thickened liquid via the DDE using the simplified inclined plane test with discrete inclination angles. [ABSTRACT FROM AUTHOR]

The thickening management index for food for dysphagia is important in enabling recognition of the rheological properties of thickened liquids, including their static and dynamic properties. One of the static properties of these liquids is the yield stress. An improvement to the simplified inclined plane test is proposed here that involves use of an automatic system for measurement of the displacements of thickened liquids on an inclined plate. The aim of this study is to investigate the relationship between the displacements of the thickened liquids and the variable thickener concentrations using an optical sensor. To measure the displacement of each thickened liquid on a clear inclined plate, an optical sensor that has a 12‐mm‐long light receiving surface is selected to form a one‐dimensional position‐sensitive detector (1D‐PSD) under the clear inclined plate. The relationship between the angle of inclination of the plate θ at which the maximum voltage occurred in the 1D‐PSD and five thickener (xanthan gum) concentrations c, ranging from 1.0 to 3.0 wt% in steps of 0.5 wt%, was investigated. It was confirmed that an approximately linear plot was obtained under the condition that θ = 8.24 c + 0.18, with the correlation R =.99 (for n = 7). This result indicated that the optical sensor composed of the 1D‐PSD can measure the displacements of thickened liquids with various thickener concentrations on the clear inclined plate automatically. [ABSTRACT FROM AUTHOR]

This study was undertaken to determine the correlation between instrumental and sensory evaluation on texture‐modified carrot puree. Texture‐modified foods (TMFs) are prescribed to dysphagia individuals to aid in the oral manipulation and facilitate swallowing of food. There is a lack of correlation between instrumental measurements and sensory attributes on TMF. Understanding this correlation will aid in the formulation of safe foods with desired sensory properties for dysphagia patients. Instrumental measurements of carrot purees were performed by back extrusion method using a texture analyzer and the attributes obtained were firmness, consistency, cohesiveness, and adhesiveness. Quantitative descriptive analysis with eight trained panelists was employed to characterize the texture of the carrot puree based on seven sensory attributes: firmness, viscous, adhesive (mouth), smoothness, adhesive (throat), rate of breakdown, and difficulty to swallow. Five thickeners, namely gellan gum, xanthan gum, Suberakaze, UNI‐PURE® Dys‐sperse instant thickener, and ULTRA‐SPERSE® M Starch, were evaluated against carrot puree without any thickener as control. The correlation results obtained from texture analysis and sensory evaluation were statistically significant (p <.05). The firmness attributes from instrumental and sensory results were positively correlated. The consistency parameter was positively correlated to sensory attribute viscous and negatively correlated to smoothness. The sensory attribute rate of breakdown was negatively correlated to instrumental parameter of cohesiveness. Lastly, instrumental adhesiveness was positively correlated to sensory attributes adhesive to mouth and throat, and difficulty to swallow. The correlation results showed a well‐designed instrumental technique can be used to understand the impact of thickeners on TMF for dysphagia subjects. [ABSTRACT FROM AUTHOR]

Correlation was investigated between instrumental characteristics obtained by extension rheological or tribological measurements and human perception while swallowing using aqueous solutions of xanthan gum and locust bean gum. Extension viscosity and the friction coefficient were measured using a capillary breakup rheometer and a rotation tribometer, respectively, as in our previous study. Results were compared with shear viscosity to clarify novelty and advantage of these mechanical parameters. It was indicated that perceived cohesiveness correlated the highest with the maximum extension viscosity immediately after the onset of extensional flow, perceived spinnability correlated with extension viscosity in high Hencky strain region, and perceived sliminess correlated with the friction coefficient at the critical point between the boundary lubrication and the mixed lubrication. These correlations were discussed and tried to validate considering biomechanics of human swallowing and food–human interactions. [ABSTRACT FROM AUTHOR]

Dysphagia is the difficulty during the progression of the bolus from the mouth to the stomach. Modifying the texture of the food is a fundamental factor for safe swallowing in patients with dysphagia since inadequate consistency can result in complications. To personalize and develop diets for dysphagia, understanding, and controlling the rheological and sensory properties of thickeners is useful. This review examines the different types of thickeners used to modify the texture of foods, as well as their influence on rheological properties and sensory attributes to efficiently manage the diet in dysphagia. The study discusses characteristics such as: hardness, viscosity, viscoelasticity, as well as sensory attributes related to rheology. The thickeners xanthan gum, methylcellulose, carboxymethylcellulose, guar gum, linseed, and chia, carboxymethylated curdlan, and konjac glucomannan were reviewed in this work. Sensory evaluations of different foods have already been carried out on some products such as: meats, carrots, soups, pates, and timbales with their modified textures. The sensory attributes measured among hydrocolloids are strongly correlated with rheological parameters. Dysphagic diets should have less hardness and adherence, but with adequate cohesiveness to facilitate chewing, swallowing to protect from aspiration and reduction of residues in the oropharynx. The use of a single type of thickener may not be ideal, their mixtures and synergistic effect can improve the viscous and elastic characteristics of foods, to obtain safe food to swallow and to improve the sensory interest of dysphagic patients. Personalized recommendations with follow‐up on swallowing approaches, respecting patient's individuality, explaining thickening agents' differences would be pertinent. [ABSTRACT FROM AUTHOR]

Instrumental characteristics from extensional rheology and tribology for aqueous xanthan gum (XG) and locust bean gum (LBG) solutions were studied in the presence or absence of simulated saliva. Extensional viscosity was calculated from the filament shrinkage behavior using a capillary breakup extensional rheometer, whereas the friction coefficient was measured using a set‐up consisting of polydimethylsiloxane substrate and a glass ball bearing on a rotational rheometer. Increase in extensional viscosity was detected immediately after initiation of extensional flow, particularly XG, and also immediately before the filament rupture, particularly LBG. Extensional viscosity tended to decrease with increased addition of simulated saliva for XG, while to increase for LBG. In both cases, effect of cations in the saliva was greater than that of mucin. From the shape of the Stribeck curve (i.e., dependence of the friction coefficient on the entrainment speed) and comparison of the friction coefficient itself, lubricity of XG was greater than that of LBG. Simulated saliva added decreased the friction coefficient for each polysaccharide through functions of cations rather than mucin. Extensional viscosity and tribological measurements revealed mechanical properties of polysaccharide solutions which cannot be determined or quantified by shear viscosity alone. [ABSTRACT FROM AUTHOR]

Oleogels can be used to provide solid‐like properties without using high levels of saturated fatty acids. In this study, the edible oleogels structure developed based on egg white protein (EWP) (5%) and xanthan gum (XG) (0%, 1%, 0.5%, and 0.75% wt/wt) complex by using aerogels system as a template for oleogel preparation. The effect of pH on the EWP‐XG mixture indicated the creation of a soluble complex of EWP‐XG in pH 5.5. The Fourier‐transform infrared spectroscopy confirmed the interaction between EWP and XG. The amount of absorbed oil was considerably higher in EWP‐XG aerogels. SEM showed a soft surface in EWP 5% aerogel, which can be the reason for its less oil absorption. The aerogel and oleogel including more XG concentration had a stronger network structure and created more elastic oleogels. The light microscopy images revealed by increasing of XG concentration, the structure of protein gel mesh became more compact and regular. The XRD patterns of the aerogels did not show any clear differences between crystallinity of the samples. Therefore, it can be concluded that the aerogels based on the structuring of EWP‐XG complexes have a high potential as a three‐dimensional network for the oil absorption and creating oleogel. [ABSTRACT FROM AUTHOR]

This study examined the effects of different hydrocolloids (guar gum, xanthan gum and gelatin) on the sensory and textural properties of pureed carrots. There were eight products involved in the study; 3D printed carrots and molded carrots without the addition of gums and with guar gum, xanthan gum and gelatin. All products were evaluated using trained panelists (n = 12) and underwent a texture profile analysis. No significant differences were found between the molded and 3D printed pureed carrots; instead, the samples were grouped based on the gum used in their production. The samples made with gelatin and xanthan gum were the hardest (texture profile analysis) and the densest samples when evaluated by the trained panelists. The 3D printing did not affect the taste properties of the pureed carrots, as they were evaluated to be similar to that of the molded carrots (p >.05). This study demonstrated that 3D printing did not affect the textural and sensory properties of pureed carrots when compared to molded carrots. However, changes in the printing parameters (infill percentage, nozzle diameter, flow rate, nozzle height) need to be evaluated to determine their effect on the sensory properties of 3D printed pureed carrots. [ABSTRACT FROM AUTHOR]

We report the optimization of oleogel formulation based on sodium caseinate (CN, 0–4 g/100 g), xanthan gum (XG, 0–1 g/100 g), guar gum (GG, 0–1 g/100 g), and drying method (freeze and oven drier) using response surface methodology to achieve the desired oil binding capacity, textural, and rheological attributes. All the selected responses were successfully fitted by a quadratic model with determination coefficient values higher than.95 with the exception of firmness values which was fitted by linear model. There were considerable increases in all the responses for the samples containing ternary mixtures of protein‐gum (CN:XG:GG) as well as binary mixtures (CN:GG and CN:XG) compared to samples containing protein or gums alone due to the synergistic effect of CN and gums on formation of highly ordered and strong gel network. Regression modeling demonstrated that freeze drying method led to significantly greater structure recovery values than those of oven drying method. The best formulation was the freeze dried oleogel containing 4 g/100 g CN, 0.43 g/100 g XG, and 0.98 g/100 g GG. Results showed that fabrication of oleogels with at least 94.5 g/100 g sunflower oil and characteristics similar to industrial shortening is feasible. [ABSTRACT FROM AUTHOR]

Herein, oscillatory rheological measurements were performed to study the interaction behavior of xanthan gum‐sage seed gum blends at different ratios (SSG‐XG: 1–0, 3–1, 1–1, 1–3, 0–1), from the dynamic viscosity behavior, relaxation spectrum, fracture properties, network parameters, and thermodynamic points of view at the temperature range of 10–90°C. Then, the coefficient of the interaction of four parameters, which were obtained from the clustering technique and Han curves, were used to investigate the interaction behavior quantitatively. At 90°C, SSG showed 2.01 extent of loss modulus overshoot, which was the highest value among different gum dispersions at different temperatures, while XG showed strain softening behavior. At 10 and 90°C, SSG and 1–1 SSG‐XG showed the highest spreadability reflected by the slope of loss tangent after flow point stress (tanδAF) of 0.52 and 0.40, respectively. The high values of ψ parameter, which represented the Gibbs free energy change, of both 1–3 and 3–1 SSG‐XG blends and the lowest entropy value of 1–3 SSG‐XG, suggested that the role of entropy change in incompatibility behavior of 1–3 SSG‐XG was higher than that of 3–1 SSG‐XG blend. With the increase in temperature from 10 to 70°C, the XG Euclidean distance from SSG decreased, while it increased from 70 to 90°C and showed the highest Euclidean distance with XG at 10°C (3.92) and 90°C (4.05). Interaction coefficients and Han curves results showed that all blends were incompatible with the lowest antagonistic behavior for 1–1 SSG‐XG dispersion at 50°C. Often, a mixture of hydrocolloids, especially xanthan gum and a galactomannan, are employed in processed foods to modify their rheological properties and cut the cost. The synergistic/non‐synergistic effect of biopolymers mixture, which is invaluable from the practical and economical points of view, seems to be mainly induced by their thermodynamic status of interaction. Our former study showed that the thermodynamic indices of mixing could be probed by mechanical parameters. On the other hands, we found that the mechanical properties of materials are highly temperature dependent. Therefore, in this study, to better investigate the effect of temperature on the biopolymers interaction, first we classified all the thermodynamic and mechanical properties (relaxation spectrum, fracture properties, and network parameters) of hydrocolloids into four classes, then one parameter was selected randomly from each class. The selected parameters were employed to investigate the synergistic/non‐synergistic effect at all temperature ranges by determining the interaction coefficient and decide on the best interaction temperature. [ABSTRACT FROM AUTHOR]

In this study, we proposed an objective classification of seven commercial hydrocolloids and four novel hydrocolloids. Total of 74 rheological parameters was generated by steady (flow behavior, hysteresis loop, single shear decay, in‐shear structural recovery experiments), dynamic (strain sweep and frequency sweep tests), and transient (creep/recovery and stress relaxation) shear measurements. Subsequently, the parameters were classified into seven categories with more than 60% similarity indexes in each group using agglomerative hierarchical clustering based on those properties related to the number of linkage, strength of linkage, distance of linkage, rupture and flow, rate of destruction, the extent of destruction, and the state of destructured samples in the absence of flow field. Fuzzy c‐means classifier used to extract patterns for each class. Our results correspond to four different classes; κ‐carrageenan and agar gum were categorized in the first class, high methoxyl pectin, xanthan, sage seed gum and basil seed gum in the second class, alginate gum and Balangu‐Shirazi seed gum in the third class, and guar gum, cress seed gum and carboxymethyl cellulose in the fourth class. Using this classification technique, complete rheological patterns can be extracted for each class. This classification provides a map for other researchers to rationally design the best test type which could describe adequately different properties of materials and avoid experiments with a similar type of parameters. The main reason for the frequent use of hydrocolloids in various industries is their ability to modify the rheology. A lot of works have been done to study the rheological behavior of many hydrocolloids in model and food systems. As there is still demand for new sources of hydrocolloids with more specific functionality in foods, probing the similarities among commercial and emerging hydrocolloids could help us to rationally design structural features in different formulations, besides gives insight into the structure–function relationship between them. This object could be attained by clustering, a part of the pattern recognition theory. Contrary to the traditional clustering methods, in which the membership of a product is exclusive for only a class, in constraint clustering by fuzzy logic methods, a partial membership can be shared by two or more classes. In this way, using the fuzzy logic clustering method, we clustered a number of commercial and novel hydrocolloids based on the steady, transient, and dynamic shear rheological properties and found a specific pattern among them. Practical applications: The main reason for the frequent use of hydrocolloids in various industries is their ability to modify the rheology. A lot of works have been done to study the rheological behavior of many hydrocolloids in model and food systems. As there is still demand for new sources of hydrocolloids with more specific functionality in foods, probing the similarities among commercial and emerging hydrocolloids could help us to rationally design structural features in different formulations, besides gives insight into the structure–function relationship between them. This object could be attained by clustering, a part of the pattern recognition theory. Contrary to the traditional clustering methods, in which the membership of a product is exclusive for only a class, in constraint clustering by fuzzy logic methods, a partial membership can be shared by two or more classes. In this way, using the fuzzy logic clustering method, we clustered a number of commercial and novel hydrocolloids based on the steady, transient, and dynamic shear rheological properties and found a specific pattern among them. [ABSTRACT FROM AUTHOR]

The flow behaviors of thickened water samples prepared with six commercial instant thickeners (A–F) were investigated at different thickness levels using the inexpensive, simple, and visual clinical tools, such as a line‐spread test (LST) and a syringe flow test developed by the International Dysphagia Diet Standardization Initiative (IDDSI). Both the flow distance value measured by the LST and the volume remaining in syringe by IDDSI flow test were compared with the apparent viscosity (ηa,50) values measured with a sophisticated computer‐controlled rheometer. The ηa,50 values of thickened water samples increased as thickener concentration increased, whereas the flow distance (cm; LST) or remaining volume (ml; IDDSI flow test) were decreased. Plots comparing ηa,50 values to LST flow distances and IDDSI volumes revealed exponential relationships (R2 = 0.926 for the LST and R2 = 0.898 for IDDSI test) between the two measurements. Such lower determination coefficient (R2) values (0.898) by IDDSI flow test seems to be due to the stickiness characteristics of starch component in starch‐based thickeners (E and F), indicating that the syringe flow test is not suitable for starch‐based thickeners. However, the thickened water samples prepared only with xanthan gum (XG)‐based thickeners (A–D) showed strong relationships (R2 = 0.972 for the LST and R2 = 0.939 for IDDSI test). These results suggest that the LST is a more reliable method than the IDDSI test for evaluating the correct and desirable viscosity for the dysphagia diet, and that the IDDSI test provides a means to predict the rheometer‐measured viscosity of water thickened with only XG‐based thickeners. Practical applications: The effective management of dysphagia requires the thickened fluids prepared with the correct and desirable viscosity. In terms of clinical practice, it is very important to observe the comparison of LST with IDDSI flow test to determine a suitable method for estimating the correct viscosity of thickened fluids. Our results showed good relationships between the rheometer‐measured viscosity and flow values measured by the LST and IDDSI test methods for the thickened water samples prepared with different foods thickeners. The IDDSI flow test may be useful as a clinical training tool for preparing thickened fluids with only XG‐based thickeners to a target level of viscosity. These results presented in this study will provide clinicians, caregivers, and patients with valuable information for IDDSI flow test as an inexpensive and simple method for measuring the correct viscosity. [ABSTRACT FROM AUTHOR]

Abstract: The effects of different setting times (15–120 min) on the rheological properties of cold thickened protein‐based beverage (PBB) samples prepared with different xanthan gum (XG)‐based food thickeners were examined. In this study, four commercial XG‐based food thickeners (coded A–D) and three commercial PBB products (whole milk, skim milk, and soybean milk) were used to prepare thickened PBB samples at a 3% thickener concentration. The fastest increases in ηa,50 values of thickened PBB samples were observed at 15 min, and at longer time periods their ηa,50 values gradually increased or remained constant with an increase in setting time (15–120 min). The magnitudes of the rheological parameters (ηa,50, K, G′, and G″) of thickened PBB samples with thickener A were significantly higher compared with those with other thickeners (coded B, C, and D). The flow and dynamic rheological properties of thickened PBB samples prepared with different XG‐based thickeners were significantly different (p < .05), demonstrating that their rheological properties were greatly affected by the type of PBB and thickener as well as the setting time. Practical statements: Food thickeners have been commonly used in the preparation of various thickened fluids with desirable rheological properties for dysphagic patients to elicit an optimal swallow response. However, among various thickened fluids, there is limited rheological information on cold thickened protein‐based beverage (PBB) (e.g., whole milk, skim milk, and soybean milk) prepared with various xanthan gum (XG)‐based thickeners. Our flow and dynamic rheological results showed that the flow and viscoelastic properties of the thickened PBB samples prepared with different food thickeners were dependent on the PBB type, thickener type, and setting time. These rheological results presented in this study will provide both thickener manufacturers and clinicians with valuable information for thickened PBB products with desirable rheological properties for safe and easy swallowing. New knowledge of the different rheological characterizations of thickened PBB can be practically applied to develop the commercial dysphagia thickeners suitable for PBB in food industry. [ABSTRACT FROM AUTHOR]

Thickened water used for hydration of patients with dysphagia and airway aspiration may change its consistency after preparation. The objective of this investigation was to evaluate the consistency stability of water thickened with maltodextrin, xanthan gum, and potassium chloride using the method developed by the International Dysphagia Diet Standardization Initiative (IDDSI). The IDDSI flow test consists of placing 10 ml of liquid inside a graduated syringe and measuring how much volume remains after a flow duration of 10 s. Pure and thickened water was tested with 1.2 g (nectar), 2.4 g (honey), and 3.6 g (pudding) of food thickener in 100 ml of water. Each consistency was measured at 8 a.m. ten times immediately after preparation, and hourly for 12 hr (from 8 a.m. to 8 p.m.), and every 24 hr for 96 hr, always at 8 a.m. With the thin liquid, nothing was left in the syringe at 10 s (zero), with the consistency nectar, the volume remaining was 5.43(0.64) ml (level 2, mildly thick), with the consistency of honey, 8.14(0.57) ml remained (level 3, moderately thick), and with the consistency pudding 9.48(0.07) ml (level 3, moderately thick). There was a small increase in consistency after 10 hr of the preparation. The consistency changed after 24 hr in preparations with mildly thick consistency (level 2) and after 48 hr with the moderately thick consistency (level 3). In conclusion, there was good stability of the thickened water at least during a 12-hr period. Practical applications This investigation demonstrated that thickened water with 1.2, 2.4, and 3.6 g of thickener with maltodextrin, xanthan gum, and potassium chloride in 100 ml of water maintains its consistency for at least 12 hr. The consistency increases after 24 hr of preparation with 1.2 g of thickener, and 48 hr with 2.4 g of thickener. As thickened water is used for treatment of patients with dysphagia and air way aspiration of liquids, it is important to know how long the preparation maintains its consistency. It is practical to prepare the thickened water only once a day for patients use. Change in consistency with time may cause ingestion problems and does not agree with the prescription given by the group of professionals who is in charge to treat the patient. Deficiency in water ingestion causes dehydration and its consequences. [ABSTRACT FROM AUTHOR]

Carrot pomace powder (CPP) is a valuable by-product of carrot processing containing nutrients and fiber and can be utilized for enrichment of gluten-free products. The main purpose of this study was to determine the effects of various levels of CPP (0, 10, 20, and 30%) and a mixture of hydrocolloids (HC) including pectin and xanthan (1.5% of each) on the quality of batter and gluten-free cakes. With increasing the level of CPP and inclusion of HC the viscosity of the batter increased significantly from 87 mPa s for the control to >7000 mPa s for 30%CCP + HC sample. The density of the control batter was 1.2 g/cm3 which reduced significantly to 0.899 g/cm3 for HC sample. The pH of the cake reduced from 7.23 to 6.78 with addition of CPP but increased slightly with inclusion of HC. The density of the cake reduced from 0.510 g/cm3 for the control to 0.395 g/cm3 for 20%CCP + C sample. The texture of the cakes became softer, more springy and chewable with addition of CPP, CPP + HC, and HC. The control sample had the lowest uniformity index (0.178) which improved with addition of CPP and CPP + HC and a highly uniform cake with a uniformity index of 0.045 was obtained for the 30%CCP + HC cake. Addition of CPP increased the dark color of the cakes while inclusion of HC had no effect on the appearance of the cake and color. It was concluded that inclusion of maximum 30%CCP and 20%CPP + HC promoted the quality and sensory attributes of gluten-free cakes. Practical applications Although different types of gluten-free products are available in the market, most of them contain insufficient amount of fiber and nutrients. Despite popularity, gluten-free cakes are poor in fiber and nutrient contents. Therefore, improving the nutritional value of these products has received an increasing attention by the food industry. Carrot pomace powder (CPP) is an available source of fiber and nutrients and hence can be utilized for enrichment of gluten-free products. This study showed that the inclusion of up to 30% CPP or 20% CPP with a mixture of xanthan and pectin (3%, 1:1) improved the quality and sensory attributes of the cakes. Industrial implications of this study may lead to new product development and improved marketing due to the enhancement of quality, sensory attributes, and nutritional value of the products. [ABSTRACT FROM AUTHOR]

The objectives of this study were to develop and compare sensory characteristics of beverages and soups thickened with different concentrations of a xanthan gum-based thickener, and to examine, using rheological measurement, whether the viscosity of the thickened liquids conformed to the recommendations of the National Dysphagia Diet (NDD) Task Force. Beverages tested included water, apple juice, orange juice, soymilk, and Yakult. The thickening agent was added to samples at concentrations of 1, 2, or 3%. Addition of the thickening agent had a significant effect on the appearance, texture, and starchy flavor, which were evaluated by descriptive sensory evaluation. The reference standards of viscosity used in sensory descriptive analysis could be useful to practitioners who have to make dysphagia diets and need to learn to make them properly. In rheological measurement, viscosity of thickened liquids in stationary state would be perceived as higher compared to that while swallowing, because of the shear thinning property. This could lead to noncompliance of the medical advice or malnutrition. It is necessary to determine optimal proportion of xanthan gum-based thickener or uncover alternatives, which have shear thinning properties lower than those of xanthan gum, for the acceptance of dysphagia patients. There was no pudding-like viscosity as classified by NDD, when prepared following instructions. Future studies should include higher concentrations of thickener to find out the concentration of the thickener resulting in pudding-like viscosity as recommended by NDD. Practical applications When a manufacturer modifies or develops a xanthan gum-based thickener, findings from this study can be utilized to understand sensory and rheological characteristics of thickened liquid. For practitioners who have to make dysphagia diets, the reference standards of viscosity used in sensory descriptive analysis could be helpful for deciding the viscosity level of thickened liquids based only on visual evaluation. This study suggests manufacturers should provide clear direction for viscosity range and thickener concentration. Medical doctors should pay close attention to the risk of aspiration when prescribing pudding-like viscosity. Dietitians should understand the variability in achieving different levels of viscosity and should educate preparers who are responsible for making dysphagia meals. [ABSTRACT FROM AUTHOR]

The viscoelastic (transient and dynamic) and time-dependent rheological behaviors of XG (xanthan gum), SSG (sage seed gum) and their blends at various ratios (1-3, 1-1, and 3-1 SSG-XG) and temperatures (10, 30, and 50C) were investigated using creep and recovery analyses. The creep compliance was converted to stress relaxation data; then, the structural kinetic model satisfactorily fitted the time-dependent relaxation modulus. Furthermore, dynamic rheology of mixtures was investigated using creep analyses. The most important contribution of the Maxwell spring to deformation (53.51%), was that corresponding to the SSG at 50C and the most important contribution of the Maxwell dashpot to the maximum deformation, were those corresponding to the XG (61.44%) and 1-3 SSG-XG (58.91%) samples both at 50C. The breakdown rate constant ( [ABSTRACT FROM AUTHOR]

Xanthan-modified konjac gel was successfully prepared using the synergistic effect between the two polysaccharides konjac glucomannan ( KGM) and xanthan gum ( XG). The effects of XG-to- KGM ratio, total polysaccharide concentration, Na2 CO3 concentration, stirring time and KCl concentration on the properties of konjac gel were investigated by single factor experiment. The xanthan-modified konjac gel was characterized, and the gel strength, gel elasticity and gel water-holding capacity were used as the indicators. The properties of konjac gel were significantly improved by the addition of XG because of the synergistic effect between KGM and XG. The result showed that the high-quality konjac gel could be obtained under the conditions of XG-to- KGM ratio, 1:5; total polysaccharide concentration, 3%; Na2 CO3 concentration, 1.5%; stirring time, 90 min; and KCl concentration, 0.6%. The results indicate that XG could be used to effectively modify and improve the quality of konjac gel, and it may expand the konjac gel application in food field. Practical Applications As a water-soluble neutral heteropolysaccharide, konjac glucomannan ( KGM) is regarded as a non-caloric food and a high-quality dietary fiber in East Asia, the role of which has been displayed in blood cholesterol and sugar reduction, weight loss, promote intestinal activity and immune function, etc. In the current study, the properties of KGM gel were modified by xanthan gel using the synergistic effect between KGM gel and xanthan gum. Then, the gel quality of KGM gel was improved, and the water-holding capacity was enhanced, and the alkali odor and bitter would be decreased, respectively. Xanthan-modified KGM gel could be used to improve and obtain products with the desired texture, and it could also be used in functional foods and dietary or health product. [ABSTRACT FROM AUTHOR]

Small amplitude oscillatory shear tests were performed to measure the elastic modulus of 1:1 xanthan-locust bean gum ( X/ L) mixed gels prepared with different total polymer concentrations (C = 0.1% to 3%). The critical concentration of X/ L mixture was determined to be 0.15%. Based on the elasticity exponent ( t) values, the concentration-modulus power-law relationship suggested the existence of two concentration regimes - a low concentration regime (0.15 ≤ C ≤ 0.5%) with tlow = 3.88 and a high concentration regime (0.5 ≤ C ≤ 3.0%) with thigh = 1.47. The elastic active network chain of X/ L mixed gels was determined by the cascade model, and compared with the similar calculation based on the classical rubber elastic theory. The cascade model clearly showed the existence of nonideality parameter and enthalpic contribution to the X/ L mixed gel. Practical applications The concentration dependence at the highest interaction might be useful for developing highly concentrated xanthan and locust bean gum mixture gels. Most studies of xanthan and locust bean gum mixtures focused only on the lower concentration regime. In this study the modulus at a higher concentration increased but eventually saturated. [ABSTRACT FROM AUTHOR]

ABSTRACT The aim of this work was to study the effect of the addition of extra virgin olive oil (EVOO) on instrumental textural properties, sensory texture profile analysis, and microstructure of fresh and frozen/thawed mashed potatoes formulated without and with added cryoprotectants (kappa-carrageenan [ κ-C] and xanthan gum [XG]). EVOO behaves as soft filler due to droplet aggregates, whereas addition of cryoprotectants led to more structured mashed potatoes (MP) thanks to the gelling properties of κ-C. Both the percentage of added EVOO and processing had a much less significant effect on the texture of the MP containing κ-C and XG, evidencing the ability of this biopolymer blend to impart freeze/thaw stability. All samples with added EVOO were perceived as significantly softer and creamier than the samples without EVOO, whereas all MP samples with added cryoprotectants were perceived as significantly thicker and creamier than those without hydrocolloids. PRACTICAL APPLICATIONS Previous studies showed that the quality after freezing and thawing may be improved by the addition of 1.5 g/kg of kappa-carageenan and 1.5 g/kg of xanthan gum, and/or incorporation of dietary fiber, improvement of mashed potatoes texture by retarding starch retrogradation and increasing water-holding capacity. Growing awareness of the link between diet and health is fast changing consumer habits, so that there has been increasing demand for foods with health-enhancing properties. Extra virgin olive oil (EVOO) has important nutritional characteristics linked to its biophenol content and has very important antioxidant properties. The results have shown that although instrumental textural data were able to explain differences in consistency perceived, structural information is needed to understand differences in creaminess. Back extrusion test is recommended to industry as practical quality control tool in the commercial production of mashed potatoes with added EVOO. [ABSTRACT FROM AUTHOR]

Whole white corn was ground, and lime, water and xanthan gum (XG, 0.5% w/w), carboxymethylcellulose (CMC, 0.5% w/w), guar gum (GG, 0.5% w/w) or a gums mix (XG, 0.25% w/w; CMC, 0.15% w/w; GG, 0.10% w/w) were added. Blends were extruded, dried and ground to obtain nixtamalized corn flour (ENCF), and they were used to make tortillas. The particle size distribution, particle size index, water absorption capacity (WAC) and water absorption index (WAI) were determined in flour; moisture content and viscoelastic characteristics (G′, G′′, tan δ) were determined in corn masa; tortillas were made, and texture (cutting force and rollability) and sensory evaluation were carried out. ENCF with XG and gums mix had the highest WAC, and tortillas were softer (33%) than tortillas from ENCF without gums. Corn masa viscoelasticity (tan δ) correlated negatively with tortilla firmness (r = − 0.84). Corn tortillas made with XG and gums mix had acceptable organoleptic characteristics. PRACTICAL APPLICATION The extrusion process allows the using of the whole corn to make tortillas and reduce processing costs and the contaminant effluents (cooking liquor). The addition of a mix of gums during extrusion makes the corn masa retain more water and modify its rheological properties, improving masa handling characteristics and tortilla textural quality. The evaluation of masa viscoelasticity with the dynamic method makes it possible to differentiate corn masas and to select the best treatments. [ABSTRACT FROM AUTHOR]

Rheological and thermal properties of xanthan produced by Xanthomonas campestris from date by-products (DBP-xanthan) and commercial xanthan were determined. DBP-xanthan gave solutions with lower apparent viscosity than commercial xanthan. However, DBP-xanthan solutions were more stable to temperature changes and ionic strength than commercial xanthan. Gradual increase of storage modulus (G′ ) as function of frequency was observed for the two polysaccharides. On the other hand, loss modulus (G″ ) remained constant for DBP-xanthan and an increase was observed for commercial xanthan. Granulometric profile indicates that DPB-xanthan particle size was lower than commercial xanthan. Differential scanning calorimetry showed that the melting temperatures (T m) and enthalpy (ΔH m) of DBP-xanthan were higher than those of commercial xanthan. These properties of DBP-xanthan are quite rare among xanthan described in the literature and give this new gum great potential for use in the field of bioindustries as thickening and stabilizing agents. PRACTICAL APPLICATIONS Xanthan gum from date by-products (DBP-xanthan) was recently produced in our laboratory. No work has been undertaken to study the rheological properties of this polysaccharide to date. Rheological and some physicals properties were compared to those of commercial xanthan. This could promote industrial use of DBPs as low-cost natural source for xanthan gum production. [ABSTRACT FROM AUTHOR]

The aim of this work is to model the variation of texture parameters in cakes during staling. The evolution was studied in layer cakes (cake A) and sponge cakes (cake B). The effect of storage temperature and the addition of fiber, xanthan gum (cake A) and emulsifier (cake B) were also studied. The best model to adjust the texture parameters variation during storage in both kinds of cakes was square root x (y = a + b * x1/2 ), except for firmness and springiness in cakes B. Firmness and springiness were adjusted the best to the linear model. In the model, y stood for the textural parameters and x for the time. a and b were related to the initial value of the studied parameter and with its change over time respectively. In both kinds of cakes, A and B, the firmness and gumminess increased, and the cohesiveness, springiness and resilience decreased, as the storage time increased. The increase in the storage temperature and the addition of fiber minimized the firmness changes in both kinds of cakes. PRACTICAL APPLICATIONS This methodology simplifies the study of cake textural parameters during storage and the result interpretation. Moreover, the correlation analysis has demonstrated that the number of textural parameters of cakes to study can be reduced. [ABSTRACT FROM AUTHOR]

The influence of κ-carrageenan, xanthan gum, guar gum, high-methoxyl (HM) pectin and gelatin addition on the rheological and microstructural properties of rennet-induced skim milk gels was investigated using a stress-controlled rheometer, syneresis measurement and confocal laser scanning microscopy. The elasticity, aggregation and gelation times of renneted skim milk decreased with increasing amounts of added κ-carrageenan, xanthan gum and guar gum, whereas they increased with increasing amounts of added HM pectin and gelatin. Syneresis of the rennet-induced skim milk gels decreased when HM pectin and gelatin were added, but increased when κ-carrageenan, xanthan gum and guar gum were added. The changes in the viscoelastic properties and syneresis of renneted skim milk were attributed to the change in the microstructure of the rennet-induced skim milk gel after the addition of the biopolymers. The branched protein network structure of the rennet-induced skim milk gel could not be formed in the presence of high concentrations of xanthan gum, κ-carrageenan and guar gum because of the formation of large protein aggregates or an open network structure with large voids. PRACTICAL APPLICATIONS There has been a steady growth in cheese sales over the last decade, mainly because of the increased use of cheese as an ingredient in a number of prepared foods, in which the cheese is used to add taste, texture and nutritional quality. However, because of the high cost associated with natural cheese production and storage, as well as its functional variability, the dairy industry has been aggressively seeking alternatives. Polysaccharides are used extensively in a variety of commercial dairy products as stabilizers and thickening or gelling agents. Furthermore, the use of polysaccharides is an attractive route to cost reduction in dairy products. However, as demonstrated in the present study, under certain conditions of biopolymer concentration, e.g., the use of some polysaccharides in cheese making can result in a decrease in the gel strength and whey holding ability of the cheese. Thus, avoiding the use of polysaccharides, which are known to phase separate when mixed with milk proteins, is highly recommended. [ABSTRACT FROM AUTHOR]

Incorporating air bubbles into foods is a technical challenge, and in all cases, the fabrication of a foam goes through a “wet foam” stage, where bubbles are diluted in the food matrix and require stabilization. Sometimes, the end product is itself a wet foam, and a popular example is ice cream. This article describes a study of structural aspects of wet foams, where the continuous phase is a fluid, by means of dynamic rheological tests. The effects of formulation and processing conditions on aerated food foams are studied, and an example is presented for ice cream mix. The incorporation of gas bubbles at volume fractions of 50% or less modifies moderately the bulk rheological properties, and their effect can be predicted by the foam limit case. The continuous phase dominates to a great part the bulk's rheological behavior, and in the case of food systems, it stems from the presence of polysaccharide thickeners. PRACTICAL APPLICATIONS This work presents an alternative approach to study the rheological properties of short life and difficult-to-sample products, such as wet food foams, in a rheo-reactor. Through the analysis of mechanical properties in oscillatory regime, the structure and stability of wet food foams can be characterized immediately after being fabricated in situ. This work presents new insights on the foaming step of ice cream mix (decoupled from the freezing step), and shows how the mechanical properties are affected by the incorporation ofbubbles, by process conditions and by the presence of thickeners and emulsifiers. This work can be a valuable guide to decide on optimal process and formulation to fabricate wet food foams (e.g., ice cream, aerated desserts) with specific mechanical properties and stability. [ABSTRACT FROM AUTHOR]

Dynamic storage modulus, G′, was used to monitor the primary retrogradation tendency of model paste systems involving finger millet starch (FMS)–tapioca and FMS–xanthan gum mixtures during cooling and curing for 48 h at 25C. Xanthan gum enhanced retrogradation during cooling and did not reduce retrogradation in cured pastes relative to control finger millet pastes. FMS–tapioca mixtures exhibited reduced retrogradation during cooling and curing. Mechanical spectra of FMS–tapioca pastes indicated extensive paste network development in hot pastes and proper gels in cooled and cured pastes. Zero shear viscosity values of FMS–tapioca mixtures at some ratios indicated enhanced viscosity over and above the sum effect of the individual component starches at the same concentration. Reduced retrogradation and network development in FMS–tapioca mixtures was attributed to some kind of a “functional energy.” These results demonstrate the applicability of starch mixtures to improve functionality and confer physical stability in food products. PRACTICAL APPLICATIONS Finger millet is a potential source of commercial native starch. Finger millet starch exhibits functional synergism with tapioca. Mixtures of the two starches can be simple and cost-effective means for thickening food systems such as meat products, soups, and gravies, and abating retrogradation effects in gruels. [ABSTRACT FROM AUTHOR]