Composition and Rheological Properties of Polysaccharide Extracted from Tamarind (Tamarindus indica L.) Seed
and Lianzhong Ai 1,*Round 1
Reviewer 1 Report
The paper “Composition and Rheological Properties of Polysaccharide Extracted from Tamarind (Tamarindus indica L.) Seed” investigates the rheological properties of polysaccharide systems for potential uses as thickening and structuring agents
The paper is interesting and well written, even though it should be checked more carefully to remove some misspellings.
Here you find my further specific comments:
Line 66: I suggest to write "… mean Mw… " instead of "… Mw…"
Line 99-101: maybe the observed shear thinning behaviour could be due also to the breakage of aggregates formed by polysaccharides at higher concentration. Is this possible in authors' opinion?
Line 106: a reference for the cited model should be given
line 112-115: in my opinion Williamson model is not suitable to describe the viscosity curves of sample at 0.5%, in this case a constant viscosity is observed (at least according to Figure 3) therefore only the parameter eta0 should be reported. This seems confirmed by the values of the critical shear rate that, for sample 0.5, is significantly greater than the largest investigated value (therefore it is extrapolated and it has no physical meaning). Similar issues, even though less relevant can be found for sample 1.0 where the critical shear rate is 1384 s^-1, larger than the measured value of 1000 s^-1.
Table 1: standard errors of all parameters have to be reported
Line 134-137: I do not agree with some definitions reported by the authors: if G' is lower than G" the system is viscoelastic with prevalent viscous properties (not only viscous properties as apparently suggested by the authors). If G' is greater than G" the system exhibit prevalent elastic behaviour (not only elastic) but this is not sufficient to define it as a "gel". Also entanglement systems exhibit G' greater than G" in specific frequency ranges (and a crossover in different ranges).
Line 181-185: "… TSP in water solution adopted a partial self-associated conformation due to hydrogen bonds and polymer entanglements at low temperature. As the temperature increased, a transition was progressively taken place from a partially ordered random broken helix conformation to disordered random coil conformation [40]." This sentence seems just a speculation of the authors, I do not see any evidence of this in experimental results. They should better describe the evidence or they should simply explain to a reader that it is a speculation, even if based on the literature.
Line 202 R is the ideal gas constant
Table 2: standard errors of all parameters have to be reported
Figure 6c: apparently only data at 2 s^-1 seem to be described by a linear model, whereas for other data a non linear curve seem to be present. This could suggest that the Arrhenius model is not working properly even if the regression coefficient is high. Moreover it is not clear for me if curves in Fig. 6c are guide for eyes or if they are the fitting results (in this case a I would expect linear trends with some deviations with respect to experimental points…)
Line 229-236: the authors are citing the effects of salts and sugars on different types of polysaccharides, the reason is not clear for me. The effects of sugars and salts depend in a relevant way on the polysaccharide structure and on functional groups, maybe the authors should explain better the reasons of these citations (for instance the could describe the analogies between their system and the cited polysaccharides).
Line 288-289: the pH of samples prepared in distilled water should be given. This could help in comparing these results (at difference concentration) with the effects of pH.
Line 296-297: "… The temperature was controlled by the circulating water device, which was coupled to a temperature control system." The temperature control system should be described, I suppose it is a Peltier system….
Line 300-302: steady state viscosity should be measured using a sequence of step shear rate tests to avoid potential time dependency. Anyway the authors are showing that upward and downward curves are overlapping quite well confirming that time dependency could be neglected and ramps are suitable to describe the material behaviour in this case. Probably this issue should be discussed by the authors.
Line 302: temperatures used to perform frequency sweep tests should be reported here
Line 302: how did the authors choose the adopted strain? did they check the linear viscoelastic behaviour?
Line 303: according to the discussion section, temperature sweeps were performed only in flow conditions (i.e. applying a constant shear rate) non in dynamic conditions, this should be clearly said. Moreover the adopted ramp rate should be reported.
Conclusion section could be improved focussing better on the main obtained results.
Author Response
Response to Reviewer 1 Comments
Point 1: I suggest to write "… mean Mw… " instead of "… Mw…".
Response 1: Thanks a lot for your help. We have replaced the expression "Mw" with "mean Mw" in the revised manuscript as shown in line 69-70.
Point 2: Maybe the observed shear thinning behaviour could be due also to the breakage of aggregates formed by polysaccharides at higher concentration. Is this possible in authors' opinion?
Response 2: Thanks a lot for your kind remind. We have found that the literature suggests that shear thinning behavior could be due to the orientation of polysaccharide macromolecules. The molecular chains gradually align themselves in the direction of increasing shear and produce less resistance. Although we have not found a reference to certificate the view that shear thinning behavior is also due to the breakage of aggregates formed by polysaccharides at higher concentration, but we think that at concentration and high shear rate, part of the aggregates will break and strengthen shear thinning behavior. We have added this speculation in the revised manuscript as shown in line 102-106, and presented below:
At high shear rate, the shear thinning behavior of the system was related to the orientation of polysaccharide macromolecules along the stream line of the flow [26], who gradually align themselves in the direction of increasing shear to reduce the resistance [42]. And the aggregates formed by polysaccharides at high concentration partially break at high shear rate may strengthen the shear thinning behavior to a certain extent.
[26] Chagas, B. S., Machado, D. L. P., Haag, R. B., Souza, C. R. D., & Lucas, E. F. Evaluation of hydrophobically associated polyacrylamide-containing aqueous fluids and their potential use in petroleum recovery. J. Appl. Polym. Sci. 2004, 91(6), 7.
[42]Alpizar-Reyes, E., Roman-Guerrero, A., Gallardo-Rivera, R., Varela-Guerrero, V., Cruz-Olivares, J., & Perez-Alonso, C. Rheological properties of tamarind (Tamarindus indica L.) seed mucilage obtained by spray-drying as a novel source of hydrocolloid. Int. J. Biol. Macromol. 2018, 107, 817-824.
Point 3: A reference for the cited model should be given.
Response 3: Thanks a lot for your kind remind. As you suggested, we have given a reference for the Williamson model in line 112 as [27].
[27] Williamson, R. V. The flow of pseudoplastic materials. Ind. Eng. Chem. 1929, 21, 1108-1111.
Point 4: In my opinion Williamson model is not suitable to describe the viscosity curves of sample at 0.5%, in this case a constant viscosity is observed (at least according to Figure 3) therefore only the parameter eta0 should be reported. This seems confirmed by the values of the critical shear rate that, for sample 0.5, is significantly greater than the largest investigated value (therefore it is extrapolated and it has no physical meaning). Similar issues, even though less relevant can be found for sample 1.0 where the critical shear rate is 1384 s^-1, larger than the measured value of 1000 s^-1.
Response 4: Thanks a lot for your kind remind. Williamson model is suitable for the fitting of pseudoplastic fluids [27, 28], so we chose this model. Since the pseudoplasticity of 0.5% and 1% TSP is not obvious and the critical shear rate is greater than the measurement range, the critical shear rate cannot be verified. As your suggestion, we have deleted the critical shear rate of TSP solution at the concentrations of 0.5% and 1.0% in line 119-120.
[27] Williamson, R. V. The flow of pseudoplastic materials. Ind. Eng. Chem. 1929, 21, 1108-1111.
[28] Zhang, H., Zhang, N., Xiong, Z., Wang, G., Xia, Y., Lai, P., & Ai, L. Structural characterization and rheological properties of beta-D-glucan from hull-less barley (Hordeum vulgare L. var. nudum Hook. f.). Phytochem. 2018, 155, 155-163.
Point 5: Table 1. Table 2. Standard errors of all parameters have to be reported.
Response 5: Thanks a lot for your kind remind. Since the equation data was fitted by Fig. 3 and Fig. 6c, the fitted equations were definite and had no standard errors. Moreover, we have referred many literature, who used the equation fitting without standard errors [27,42,43].
[28] Zhang, H., Zhang, N., Xiong, Z., Wang, G., Xia, Y., Lai, P., & Ai, L. Structural characterization and rheological properties of beta-D-glucan from hull-less barley (Hordeum vulgare L. var. nudum Hook. f.). Phytochem. 2018, 155, 155-163.
[42]Alpizar-Reyes, E., Roman-Guerrero, A., Gallardo-Rivera, R., Varela-Guerrero, V., Cruz-Olivares, J., & Perez-Alonso, C. Rheological properties of tamarind (Tamarindus indica L.) seed mucilage obtained by spray-drying as a novel source of hydrocolloid. Int. J. Biol. Macromol. 2018, 107, 817-824.
[43] Reinoso, D., Martin-Alfonso, M. J., Luckham, P. F., & Martinez-Boza, F. J. Rheological characterisation of xanthan gum in brine solutions at high temperature. Carbohydr. Polym. 2019, 203, 103-109.
Point 6: I do not agree with some definitions reported by the authors: if G' is lower than G" the system is viscoelastic with prevalent viscous properties (not only viscous properties as apparently suggested by the authors). If G' is greater than G" the system exhibit prevalent elastic behaviour (not only elastic) but this is not sufficient to define it as a "gel". Also entanglement systems exhibit G' greater than G" in specific frequency ranges (and a crossover in different ranges).
Response 6: Thanks a lot for your comments. We found that in general, if G' > G'', the materials reveal the elastic properties that behave as “solid-like”, and if G' < G'', the solutions expose the viscous properties which are observed to be more ‘‘liquid-like”. So we have made correction according to the your comments and the literature in line 143-145, and presented below:
In general, if G' < G'', the solution is viscoelastic with prevalent viscous properties which are observed to be more ‘‘liquid-like”, while G' > G'', the system will exhibit prevalent elastic properties [11, 33, 37, 47].
[11] Busato, A. P., Reicher, F., Domingues, R., & Silveira, J. L. M. Rheological properties of thermally xyloglucan gel from the seeds of Hymenaea courbaril. Mater. Sci. Eng., C 2009, 29(2), 410-414.
[37] Ma, F., Zhang, Y., Liu, N., Zhang, J., Tan, G., Kannan, B., Liu, X., & Bell, A. E. Rheological properties of polysaccharides from Dioscorea opposita Thunb. Food Chem. 2017, 227, 64-72.
[47] Choppe, E., Puaud, F., Nicolai, T., & Benyahia, L. Rheology of xanthan solutions as a function of temperature, concentration and ionic strength. Carbohydr. Polym. 2010, 82(4), 1228-1235.
Point 7: "… TSP in water solution adopted a partial self-associated conformation due to hydrogen bonds and polymer entanglements at low temperature. As the temperature increased, a transition was progressively taken place from a partially ordered random broken helix conformation to disordered random coil conformation [40]." This sentence seems just a speculation of the authors, I do not see any evidence of this in experimental results. They should better describe the evidence or they should simply explain to a reader that it is a speculation, even if based on the literature.
Response 7: Thanks a lot for your suggestion. Due to polymer entanglements and hydrogen bonds, food thickeners, gels, and stabilizers will adopt a partial self-associated conformation at low temperature. And when the temperature increased, the molecular chain will transform the conformation form partially ordered random to disordered random. Therefore, we speculated that the conformation of TSP solution is similar to major food thickeners. We have made corrects in line 190-194, and presented below:
It could be speculated that TSP adopt a partial self-associated conformation in water solution due to hydrogen bonds and polymer entanglements at low temperature and a transition was progressively taken place from a partially ordered random broken helix conformation to disordered random coil conformation as the temperature increased [41].
[41] Ross-Murphy, S. B. Structure-property relationships in food biopolymer gels and solutions. J. Rheol. 1998, 39(39), 1451-1463.
Point 8: R is the ideal gas constant.
Response 8: Thank you for your kind remind. The literature we have referred about R expressed as follows: R is the universal law gas constant [42]; R is the natural gas constant [45]; R is the universal gas constant [46]. As our understanding, we have adopted your comment and modified the definition of “R” as the ideal gas constant in line 211.
[42] Alpizar-Reyes, E., Roman-Guerrero, A., Gallardo-Rivera, R., Varela-Guerrero, V., Cruz-Olivares, J., & Perez-Alonso, C. Rheological properties of tamarind (Tamarindus indica L.) seed mucilage obtained by spray-drying as a novel source of hydrocolloid. Int. J. Biol. Macromol. 2018, 107, 817-824.
[45] Mehdizadeh, H., & Najafi Kani, E. Rheology and apparent activation energy of alkali activated phosphorous slag. Constr. Build. Mater. 2018, 171, 197-204.
[46] Timmons, J., Falzone, G., Balonis, M., Bauchy, M., & Sant, G. Anomalous variations in the viscous activation energy of suspensions induced by fractal structuring. J. Colloid Interface Sci. 2018, 530, 603-609.
Point 9: Apparently only data at 2 s^-1 seem to be described by a linear model, whereas for other data a non linear curve seem to be present. This could suggest that the Arrhenius model is not working properly even if the regression coefficient is high. Moreover it is not clear for me if curves in Fig. 6c are guide for eyes or if they are the fitting results (in this case a I would expect linear trends with some deviations with respect to experimental points…)
Response 9: Thanks a lot for your comments. Since Arrhenius’ law is the main procedure to determine the Ea [42, 45], which was applied to investigate the temperature dependence of macromolecule polymer [46], we have chose Arrhenius’ law to study the Ea of TSP solution. In Fig. 6c, the previous line was not the linear trends of data but the line between points. We have re-created the figure and added the linear trends in Fig. 6c, which were linear curves with high regression coefficient. So we believe that the Arrhenius model is working properly in the fitting results. The figure is as following:
Figure 6c. Effects of temperature on the arrhenius plots of TSP (2%, w/v)
at different shear rate
[42] Alpizar-Reyes, E., Roman-Guerrero, A., Gallardo-Rivera, R., Varela-Guerrero, V., Cruz-Olivares, J., & Perez-Alonso, C. Rheological properties of tamarind (Tamarindus indica L.) seed mucilage obtained by spray-drying as a novel source of hydrocolloid. Int. J. Biol. Macromol. 2018, 107, 817-824.
[45] Mehdizadeh, H., & Najafi Kani, E. Rheology and apparent activation energy of alkali activated phosphorous slag. Constr. Build. Mater. 2018, 171, 197-204.
[46] Timmons, J., Falzone, G., Balonis, M., Bauchy, M., & Sant, G. Anomalous variations in the viscous activation energy of suspensions induced by fractal structuring. J. Colloid Interface Sci. 2018, 530, 603-609.
Point 10: The authors are citing the effects of salts and sugars on different types of polysaccharides, the reason is not clear for me. The effects of sugars and salts depend in a relevant way on the polysaccharide structure and on functional groups, maybe the authors should explain better the reasons of these citations (for instance the could describe the analogies between their system and the cited polysaccharides).
Response 10: Thank you very much for your comments. We have rewritten this part in line 234-244 as following:
The decrease of apparent viscosity of TSP with the addition of Na+ could be due to the charge screening of electrostatic repulsions of the tri-saccharide side-chain, which led to a more compact conformation and caused a reduction in hydrodynamic size of the molecule [38].The apparent viscosity of xanthan also decreased with the existence of Na+ [38]. However, K+ can enhance the apparent viscosity of xanthan gum and gellan solutions, since the association of charged helical structures facilitated in different ways [47,48]. The effects of sucrose on polysaccharides could be due to that sucrose reduced the free water of the system and enhanced the interaction between the polysaccharide molecular chains, which contributed to the viscosity of the solution system [38, 50]. The apparent viscosity increasing with increasing sucrose concentration also existed for High-methoxylated (HM) pectin [49] and xanthan gum [50].
[38] Bak, J. H., & Yoo, B. Intrinsic viscosity of binary gum mixtures with xanthan gum and guar gum: Effect of NaCl, sucrose, and pH. Int. J. Biol. Macromol. 2018, 111, 77-81.
[47] Choppe, E., Puaud, F., Nicolai, T., & Benyahia, L. Rheology of xanthan solutions as a function of temperature, concentration and ionic strength. Carbohydr. Polym. 2010, 82(4), 1228-1235.
[48] Xu, L., Dong, M., Gong, H., Sun, M., & Li, Y. Effects of inorganic cations on the rheology of aqueous welan, xanthan, gellan solutions and their mixtures. Carbohydr. Polym. 2015, 121, 147-154.
[49] Morris, E. R., Powell, D. A., Gidley, M. J., & Rees, D. A. Conformations and interactions of pectins: I. Polymorphism between gel and solid states of calcium polygalacturonate. J. Mol. Biol. 1982, 155(4), 507-516.
[50] Saggin, R., & Coupland, J. N. Rheology of xanthan/sucrose mixtures at ultrasonic frequencies. J. Food Eng. 2004, 65(1), 49-53.
Point 11: The pH of samples prepared in distilled water should be given. This could help in comparing these results (at difference concentration) with the effects of pH.
Response 11: Thanks a lot for your kind remind. We have added the pH of samples in distilled water as pH 6.87 ± 0.02 in line 301.
Point 12: "… The temperature was controlled by the circulating water device, which was coupled to a temperature control system." The temperature control system should be described, I suppose it is a Peltier system
Response 12: Thanks a lot for your kind remind. We have made correction in line 308-309 and presented below:
The temperature was controlled by the circulating water device, which was coupled to the Peltier system (a temperature control system).
Point 13: Steady state viscosity should be measured using a sequence of step shear rate tests to avoid potential time dependency. Anyway the authors are showing that upward and downward curves are overlapping quite well confirming that time dependency could be neglected and ramps are suitable to describe the material behaviour in this case. Probably this issue should be discussed by the authors.
Response 13: Thank you very much for your comments. The time dependency is important in rheological behavior, which should be discussed in the manuscript. We have added this part in line 134-140 and presented below:
In addition, the time dependency is connected to the thixotropy concept -- at a constant shear rate, the measured shear stress or viscosity of thixotropic material will decrease with time and finally steady out to a constant value, which could be characterized by considering a ramp-up and ramp-down of shear imposed in a rotational rheometer [56]. Since the upward and downward curves are overlapping quite well (Fig. 3), the rate of structure breakdown is similar to that of its reconstruction [57]. Therefore, the time dependency could be neglected and ramps are suitable to describe rheological behavior of TSP solution.
[56] Yoon, C., Heister, S. D., & Campanella, O. H. Modeling gelled fluid flow with thixotropy and rheological hysteresis effects. Fuel, 2014, 128: 467-475.
[57] Liu, G., Liu, Y., Wang, Z., Lei, Y., Chen Z., & Deng, L. The effects of temperature, organic matter and time-dependency on rheological properties of dry anaerobic digested swine manure. Was. Man., 2015, 38: 449-454.
Point 14: Line 302: temperatures used to perform frequency sweep tests should be reported here.
Response 14: Thanks a lot for your kind remind, and we have added the temperature parameter in line 313 as following:
Viscosity curves were obtained by applying an increasing shear rate (1-1000 s−1) and a decreasing shear rate (1000-1 s−1) at 25 °C.
Point 15: How did the authors choose the adopted strain? did they check the linear viscoelastic behaviour?
Response 15: Thanks a lot for your kind remind. We have checked the linear viscoelastic behaviour that G' and G'' are almost unchanged in the test strain range of 0.1 - 100%, so we chose 2% of strain to carry out the subsequent experiments. We have added “Supplementary Figure 2. Strain dependency of shear modulus G'(storage) and G''(loss) of TSP at different concentrations at 25 °C” in the Supplementary and presented below:
Supplementary Figure 2. Strain dependency of shear modulus G'(storage) and G''(loss) of TSP at different concentrations at 25 °C
Point 16: According to the discussion section, temperature sweeps were performed only in flow conditions (i.e. applying a constant shear rate) non in dynamic conditions, this should be clearly said. Moreover the adopted ramp rate should be reported.
Response 16: Thanks a lot for your kind remind. We have added the ramp time and shear rate in line 316-317, and presented below:
For thermos-stability study, temperature sweeps were performed by heating from 5 to 85 °C, and subsequent cooling from 85 to 5 °C with 5 °C/min of ramp time at a constant shear rate (2 s−1, 60 s−1, 200 s−1).
Point 17: Conclusion section could be improved focusing better on the main obtained results.
Response 17: Thank you very much for your comments. We have rewritten the Conclusion and presented below:
This study investigated the chemical components and rheological properties of tamarind seed polysaccharide collected from Yunnan, China. The main monosaccharides of TSP were glucose, xylose and galactose at a molar ratio of 2.9: 1.8: 1.0, with the Mw of 1735 kDa. TSP presented the pseudoplastic behavior in water solution. The pH-resistance of TSP was excellent, with the tolerance range of pH 1-10. The apparent viscosity of the TSP solution decreased slightly with increasing temperature and ions concentration, while it increased with sucrose concentration. Temperature, pH, salt ions, as well as the sucrose concentration were identified to be insignificantly affected the rheological properties of TSP. With the aim to investigating the application of TSP in acidic beverage, high temperature processing foodstuff, high-salt and high-sugar food as thickener and stabilizer, further study will focus on the interaction of TSP with food components.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
GENERAL COMMENTS
The authors should explain in the manuscript the novelty of their studies clearly because, nowadays, there are a lot of studies that include the composition, the characterization and/or the rheological properties of the polysaccharide extracted from different species from Tamarind seeds, some of them included in the manuscript by the authors (references 1, 15, 16, 18, 25, 41…) and others that have not been included as for example:
Chawananorasest, Khanittha et al., Molecules, 21 (6), 2016.
Erik Alpizar-Reyes et al., Journal of Food Engineering, 209, 68-75, 2017.
C. Chandra Mohan et al., Carbohydrate Polymers, 186, 394-401, 2018.
Han, Minghui, et al., Journal of Biobased Materials and Bioenergy, 12 (2), 175-183, 2018.
…
SPECIFIC COMMENTS
Introduction
Last paragraph: Authors should justify the selection of the parameters (concentration, pH, temperature and salt ions) for the rheological study of the TSP suspensions, in order to clarify the objective of the investigation. Also, they should include in this paragraph the study of the sucrose presence, whose results are included later (section 2.7).
Results and discussion
Although the results obtained are interpreted appropriately and are significant, all of them are consistent or similar to other studies, then the authors should clarify the novelty of their study.
Materials and methods
The section “3.1. Materials” should be completed because there are several materials that are not included: citric acid, sucrose, salts (Na+, K+, Ca2+), acid and alkali used to adjust the pH in the rheological studies, ethanol, ...
Author Response
Response to Reviewer 2 Comments
Point 1: Introduction: Last paragraph: Authors should justify the selection of the parameters (concentration, pH, temperature and salt ions) for the rheological study of the TSP suspensions, in order to clarify the objective of the investigation. Also, they should include in this paragraph the study of the sucrose presence, whose results are included later (section 2.7).
Response 1: Thank you very much for your comments. and we have added the aim and the level of the parameters we chose for the rheological study of the TSP suspensions in line 58-59.
Point 2: Although the results obtained are interpreted appropriately and are significant, all of them are consistent or similar to other studies, then the authors should clarify the novelty of their study.
Response 2: Thank you very much for your comments. Firstly, the raw material of TSP was the tamarind seeds collected from Yunnan, China, which has not reported in the literature yet. Moreover, this manuscript systematically show the rheological stability of TSP with different factors and wide levels, which was less to discuss in other literature. We have added this part in the part of Introduction as line 54-59:
The current study tried to extract polysaccharide from tamarind seeds collected from Yunnan, China, which has not reported yet, and chemically characterize the compositions of TSP. With the aim of systematically investigate the rheological properties and stability of TSP, we chose several different factors with the wide range of levels to studied the TSP solutions at different concentrations (0.5%, 1%, 1.5%, 2%, 4%, 8%, 10%), pH (1, 4, 7, 10, 13), temperature (5 - 85 °C), salt ions (Na+, K+, Ca2+) and sucrose (10%, 20%, 30%).
Point 3: Materials and methods: The section “3.1. Materials” should be completed because there are several materials that are not included: citric acid, sucrose, salts (Na+, K+, Ca2+), acid and alkali used to adjust the pH in the rheological studies, ethanol, ...
Response 3: Thanks a lot for your kind remind. We have added all the materials we used in line 257-260 and presented below:
Ethanol, phenol, citric acid, boric acid, acetonitrile, NaNO3, TFA, HCl, H2SO4, NaOH, KBr, NaCl, KCl, CaCl2 and sucrose were purchased from Yuanye Bio-technology Co. (Shanghai, China). Analytical grade chemicals were used. All reagents used were of analytical grade unless otherwise specified.
Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
Although the authors have improved the manuscript, in my opinion the novelty of the study is low.
English language and style should be checked before the manuscript will be accepted.
Author Response
Response to Reviewer 2 Comments
Point 1: Although the authors have improved the manuscript, in my opinion the novelty of the study is low.
Response 1: Thank you very much for your comments. For the novelty, in addition to the source of raw materials of TSP and systematical rheological stability of TSP we have replied in Round 1, the results of the effect of pH on the rheological property of TSP are different from the previous research. It indicated that TSP possessed excellent pH-resistance, which might be suitable for applications in acidic and weakly alkaline beverage. We have made the corrections in line 168-170:
It is perceivable that TSP solution was stable at acidic and weakly alkaline environment. It is in contrast to Alpizar-Reyes’s [42] research, in which the apparent viscosity of TSP decreases with the decreasing pH. The decreasing viscosity may be due to an increase in charge density [58], which promotes a contraction of the TSP molecules.
[42] Alpizar-Reyes, E., Roman-Guerrero, A., Gallardo-Rivera, R., Varela-Guerrero, V., Cruz-Olivares, J., & Perez-Alonso, C. Rheological properties of tamarind (Tamarindus indica L.) seed mucilage obtained by spray-drying as a novel source of hydrocolloid. Int. J. Biol. Macromol. 2018, 107, 817-824.
[58] Chen, R. H., & Chen, W. Y. Rheological properties of the water-soluble mucilage of a green laver, monostroma nitidium. J. Appl. Phycol., 2001, 13(6), 481-488.
Point 2: English language and style should be checked before the manuscript will be accepted.
Response 2: Thanks a lot for your kind remind. We have checked the English language and style of our manuscript and made some corrections in expression, tense, singular and plural. All the revised part have been marked in the manuscript. These changes will not influence the content and framework of the paper.
