Search

The aqueous solution of xanthan gum has high viscosity and pseudoplastic behavior. This research aimed to analyze the effect of microwave pretreatment at different time intervals (0, 1, 2, and 3 min) on the viscosity and rheological behavior of xanthan gum solution. The results showed that the apparent viscosity of xanthan gum solution (untreated solution) reduced from 0.177 Pa.s to 0.036 Pa.s with increasing shear -rate from 12.2 s-1 to 171.2 s-1. Also, the apparent viscosity of xanthan gum solution reduced from 0.070 Pa.s to 0.046 Pa.s with increasing the microwave pretreatment time from 0 to 3 min (shear -rate=61.2 s-1 ). The flow behavior of all samples was successfully modeled with Power law, Bingham, Herschel -Bulkley, and Casson models, and the Herschel -Bulkley model was selected as the better model to describe the flow behavior of xanthan gum solutions. The Herschel -Bulkley model had an acceptable performance with the maximum correlation coefficient (r) (higher than 0.9032) and the minimum sum of squared error (SSE) (lower than 0.7165) and root mean square error (RMSE) (lower than 0.2552). The yield stress and consistency coefficient (Herschel -Bulkley model) of xanthan gum solution increased from 0.095 Pa to 0.450 Pa, and from 0.659 Pa.sn to 0.811 Pa.sn, with increasing microwave pretreatment time from 0 to 3 min, respectively. The flow behavior index (Herschel - Bulkley model) of xanthan gum solutions decreased from 0.440 to 0.328 while the duration of microwave treatment increased. [ABSTRACT FROM AUTHOR]

Dispersion of Basil seed gum has high viscosity and exhibits shear-thinning behavior. This study aimed to analyze the influence of microwave treatment (MT) at various time intervals (0, 1, 2, and 3 min) on the viscosity and rheological behavior of Basil seed gum dispersion (0.5%, w/v). The finding of this study revealed that the apparent viscosity of Basil seed gum dispersion (non-treated dispersion) reduced from 0.330 Pa.s to 0.068 Pa.s as the shear rate (SR) increased from 12.2 s−1 to 171.2 s−1. Additionally, the apparent viscosity of the Basil seed gum dispersion reduced from 0.173 Pa.s to 0.100 Pa.s as the MT time increased from 0 to 3 min (SR = 61 s−1). The rheological properties of gum dispersion were successfully modeled using Power law (PL), Bingham, Herschel–Bulkley (HB), and Casson models, and the PL model was the best one for describing the behavior of Basil seed gum dispersion. The PL model showed an excellent performance with the maximum r-value (mean r-value = 0.942) and the minimum sum of squared error (SSE) values (mean SSE value = 5.265) and root mean square error (RMSE) values (mean RMSE value = 0.624) for all gum dispersion. MT had a considerable effect on the changes in the consistency coefficient (k-value) and flow behavior index (n-value) of Basil seed gum dispersion (p < 0.05). The k-value of Basil seed gum dispersion decreased significantly from 3.149 Pa.sn to 1.153 Pa.sn (p < 0.05) with increasing MT time from 0 to 3 min. The n-value of Basil seed gum dispersion increased significantly from 0.25 to 0.42 (p < 0.05) as the MT time increased. The Bingham plastic viscosity of Basil seed gum dispersion increased significantly from 0.029 Pa.s to 0.039 Pa.s (p < 0.05) while the duration of MT increased. The Casson yield stress of Basil seed gum dispersion notably reduced from 5.010 Pa to 2.165 Pa (p < 0.05) with increasing MT time from 0 to 3 min. [ABSTRACT FROM AUTHOR]

The present study aims to determine the influence of edible organic acids (ascorbic, citric, malic, and tartaric) at two concentrations (0.5, and 1 %) on the viscosity and rheological behavior of xanthan gum dispersion (0.2%, w/v). The results of this study showed that the apparent viscosity of xanthan gum dispersion reduced as the shear rate (SR) increased (shear-thinning behavior). Furthermore, the apparent viscosity of the xanthan gum dispersion decreased as the organic acid concentration increased. The highest decrease in viscosity was related to 1% citric acid and the lowest was related to 0.5% ascorbic acid. The rheological behavior of xanthan gum dispersion was successfully modeled using Power law, Bingham, Herschel-Bulkley, and Casson models, and the Power law model was the best one for describing the behavior of xanthan gum dispersion containing edible organic acids. The Power law model showed good performance with the maximum r-value (mean r-value=0.993) and least sum of squared error (SSE) values (mean SSE value=0.115) and root mean square error (RMSE) values (mean RMSE value=0.046) for all samples. The consistency coefficient values of the samples (Power law and Herschel- Bulkley models) reduced as the acid percent was increased. The sample containing 1% citric acid had the lowest consistency coefficient and the sample containing 0.5% ascorbic acid had the highest consistency coefficient. Based on the results of this research, the use of xanthan gum in food products containing high concentrations of citric acid is not recommended. [ABSTRACT FROM AUTHOR]

This study aimed to analyze the influence of microwave treatment (MT) at various time intervals on the viscosity and flow behavior of Wild sage seed gum (WSSG) dispersion (0.2%, w/v). The flow behavior of WSSG dispersions were calculated from the resulting flow curves using four flow behavior models (Power law (PL), Bingham, Herschel-Bulkley (HB), and Casson). The fit quality of the selected models was evaluated using correlation coefficient (r), sum of squared error (SSE), and root mean square error (RMSE). It was observed that the apparent viscosity of WSSG dispersion reduced from 68 mPa.s to 19 mPa.s as the shear rate (SR) increased from 12.2 s-1 to 171.2 s-1 . Additionally, the apparent viscosity of the samples reduced from 34 mPa.s to 28 mPa.s as the MT time increased from 0 to 3 min (SR=49 s-1 ). The HB model, which is a combination of Bingham and PL models, fitted the data very well with an overall r of more than 0.9990 and, SSE and RMSE values of lower than 0.0123, and, 0.0310, respectively, therefore, used to describe the shear stress (SS) and apparent viscosity of WSSG dispersions. The consistency coefficient of WSSG dispersion decreased significantly from 0.185 Pa.sn to 0.155 Pa.sn (p<0.05) with increasing MT time from 0 to 3 min. Also, the flow behavior index (PL and HB models) of dispersions increased as the MT time increased. [ABSTRACT FROM AUTHOR]