Guar gum is a widely used ingredient in food processing industry. This work highlights the use of guar gum as a flocculant aid in potable water treatment. Current practice of using synthetic flocculants such as polyacryl-amide has raised controversies of acrylamide residues in water and thereby increasing health risk of the population. The flocculating effect of guar gum on the settling characteristics of flocs in a bench-scale potable water clarification process is presented in this work. Data from two experimental runs, namely, run A (guar gum and primary coagulant) and run B (primary coagulant only), were used to plot settling velocity distribution curves (SVDC). Observation of these curves revealed that guar gum increased the proportion of destabilised colloidal impurities settling above a stated minimum velocity. It was found that guar gum may be used along with alum to reduce raw water turbidity from 26.5 to 1.0. It may be concluded that guar gum can be used as a safer alternative to polyacrylamide in water treatment for drinking or food processing purposes.

The aim of this study was to determine thermal properties of pseudoplastic polysaccharides (guar gum, κ-carrageenan and xanthan gum) which find many applications as food hydrocolloids in food industry. There was an obvious relationship between thermal dependency of heats of fusion of hydrocolloids in powder form and activation parameters of hydrodynamic flow in solutions, respectively. Results of thermal analysis confirmed, that powder samples of hydrocolloids as typical foodstuffs of low moisture content less than 15 w% after room conditioning, exhibited varying ability to bind water as depending on their molecular structure. The peak temperature of the endothermic polysaccharide order-disorder phase transition process was found in the temperature range of 50–85 °C. It was influenced simultaneously by the applied heating rate and the samples moisture content. Studied samples moisture content was ranging between 9–40 w.% as was obtained after different conditioning. Observed reaction enthalpy (ΔH) associated with phase transition and water evaporation (proved by appropriate weight loss of the samples Δmw) was ranging from 140 to 670 J/g. Activation energy (Eₐ) of this process in powder samples was calculated from the kinetic parameters using three kinetic models developed by Friedman, Kissinger and model-free kinetics. The latter kinetic models were compared with the Arrhenius model, which was used to determine Eₐ of polysaccharide solutions on reflecting sensitivity of their molecular structure to the temperature and the solvent. According to the Arrhenius model, there were obtained the highest values of Eₐ for κ-carrageenan solutions, indicating the highest resistance of their molecular structure to temperature. This fact can be related to the observed the lowest value of the reaction enthalpy in the case of powder samples, suggesting that energy obtained during the order-disorder transition to change the carrageenan powder structure is limited. On the other hand, xanthan gum was the least temperature dependent sample; activation energy of xanthan solutions was only in the range of 2–6 kJ/mol. Concurrently, ΔH of xanthan powder was determined as the largest of all samples under study. In general, there was found an indirect relationship between activation energy of the solutions determined by viscometry and reaction enthalpy of the powders determined by thermal analysis. Results of the Arrhenius model also indicate that the energy necessary to promote viscous flow of solutions is higher for hydrocolloids in distilled water rather than in 0.07 M KCl aqueous solutions, suggesting the suppression of the polyelectrolyte effect. In both cases, Eₐ was substantially reduced by application of higher shear rate.

To understand whether soluble fiber (SF) with high water-binding capacity (WBC), swelling capacity (SC) and fermentability reduces food intake and whether it does so by promoting satiety or satiation or both, we investigated the effects of different SFs with these properties on the food intake in rats. Thirty-two male Sprague-Dawley rats were randomized to four equal groups and fed the control diet or diet containing 2% konjac flour (KF), pregelatinized waxy maize starch (PWMS) plus guar gum (PG), and PWMS starch plus xanthan gum (PX) for three weeks, with the measured values of SF, WBC, and SC in the four diets following the order of PG > KF > PX > control. Food intake, body weight, meal pattern, behavioral satiety sequence, and short-chain fatty acids (SCFAs) in cecal content were evaluated. KF and PG groups reduced the food intake, mainly due to the decreased feeding behavior and increased satiety, as indicated by decreased meal numbers and increased inter-meal intervals. Additionally, KF and PG groups increased concentrations of acetate acid, propionate acid, and SCFAs in the cecal contents. Our results indicate that SF with high WBC, SC, and fermentability reduces food intake—probably by promoting a feeling of satiety in rats to decrease their feeding behavior.

In this study, oil-in-water emulsions made of medium-chain triglycerides (MCT), mucilage from Dioscorea opposita (DOM), and food-grade polysaccharides (guar gum [GG], xanthan gum [XG] and pectin [Pec]) were prepared using high-pressure homogenisation. The droplet size distributions, microstructure, turbidity, interfacial tension, creaming index, and stability of emulsions were investigated and compared with those of DOM, GG, XG and Pec. The results showed that 0.4 wt% food-grade polysaccharides (GG, XG, and Pec) with 2 wt% DOM contributed more to the stability of the emulsion during storage. In particular, low concentrations of pectin and DOM emulsions presented smaller droplet size distribution, in the range of 86.34–111.30 nm. Hence, DOM has synergistic effects with food-grade polysaccharides, which could improve the stability of emulsions, suggesting that mucilage from Dioscorea opposita has good potential for use as a natural emulsifier.

Objective: The aim of this study was to investigate the effects of supplementation of dietary soluble fibers with high water-binding capacity (WBC) and swelling capacity (SC) on gastrointestinal tract mass, physicochemical properties of digesta, gastrointestinal mean retention time (MRT), body weight, and food intake in male rats. Methods: Thirty-two male Sprague-Dawley rats were randomized to four equal groups and fed the control diet or diet containing 2% konjac flour (KF), pregelatinized waxy maize starch plus guar gum (PWMS+GG), andPWMS plus xanthan gum (PWMS+XG) for three weeks. Results: WBC and SC of diets followed the order of PWMS+GG > KF > PWMS + XG > control. PWMS+GG and KF groups had a lower average daily food intake than the control group, but all the groups showed no difference in final body weightand the weight gain rate. The high WBC and SC of the PWMS+GG and KF groupsled to an increase of WBC and SC in the stomach digesta, and a gain of the cecal digesta weight, due to increased cecal moisture content. Conclusion: The inclusion of the novel fiber, PWMS+GG, in the diet of male rats appears to facilitate the modulation of WBC and SC of stomach digesta and the reduction of food intake.