Pine Bark as a Potential Source of Condensed Tannin: Analysis through Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), and Energy Dispersive X-ray (EDX)
, Sergio Obed Ramírez-Cruz 2, Faustino Ruiz-Aquino 2,*, Luis Humberto Robledo-Taboada 3, Marco Antonio Sánchez-Medina 4, Oscar Francisco Mijangos-Ricárdez 2, Rosalío Gabriel-Parra 2, Mario Ernesto Suárez-Mota 2, Ramiro Puc-Kauil 5 and Jhazeel Porcallo-Vargas 6
Round 1
Reviewer 1 Report
1、Although different tree ages are mentioned, the effect of different tree ages on tannin extraction is not explained in detail.
2、The effect of trees grown by different soil types on the amount of tannin extraction is not detailed, please provide relevant literature support.
3、When extracting tannins from tree species, economic effects and whether industrial production is occur should be considered.
4、The best time to cite references is almost 5 years.
5、The SEM plot scale is as clear as possible.
English should be improved
Author Response
Response to Reviewer 1 Comments
Point 1. Although different tree ages are mentioned, the effect of different tree ages on tannin extraction is not explained in detail.
Response 1: The effect of different tree ages on tannin extraction is explained in lines 248 – 256, highlighted in green.
Point 2. The effect of trees grown by different soil types on the amount of tannin extraction is not detailed, please provide relevant literature support.
Response 2: The effect of trees grown by different soil types on the amount of tannin extraction is detailed in lines 257 – 265, highlighted in green.
Point 3. When extracting tannins from tree species, economic effects and whether industrial production is occur should be considered.
Response 3: The most important industrial applications and economic effects of tannin extraction are explained in lines 85 to 90, and 96 to 98, highlighted in green.
Point 4. The best time to cite references is almost 5 years.
Response 4: We include recent references in this review.
Point 5. The SEM plot scale is as clear as possible.
Response 5: The SEM plot scales was improved.
Author Response File: 
Author Response.docx
Reviewer 2 Report
- Line 120, please explain in more detail about "the best phenotypic characteristic"
- L 141, please add reference
- section 3.1, authors mentioned that there are several studies use different solvent for tannin extraction. So please explain why authors select ethanol, what's authors rational?
- are these ref no 24 and 32 using the same species ? if not, it's not fair to make this conclusion
- fig 5, why must be collagen? this composite molecule was pop up out of nowhere, no supported rational
- the major concern is that this manuscript is more like investigation research, by extract and characterize tannin from 5 species. However the key core of this study was absence, which make it more like report not a research
-minor revision
Author Response
Response to Reviewer 2 Comments
Point 1. Line 120, please explain in more detail about "the best phenotypic characteristic"
Response 1: The best phenotypic characteristic is detailed in lines 135, 136, highlighted in yellow
Point 2. - L 141, please add reference
Response 2: added reference, line 158.
Point 3. - section 3.1, authors mentioned that there are several studies use different solvent for tannin extraction. So please explain why authors select ethanol, what's authors rational?
Response 3: The use of different solvents for the extraction of tannins, and the explanation of their use is given in lines 91-95, highlighted in yellow.
Point 4. - are these ref no 24 and 32 using the same species ? if not, it's not fair to make this conclusion
Response 4: In reference 24, the study was conducted with Pinus ayacahuite in a different study area.
Point 5. - fig 5, why must be collagen? this composite molecule was pop up out of nowhere, no supported rational
Response 5: Tannins react with the basic groups of protein in leather matrix. At first, hydroxyl groups (OH) of tannins bind with the active collagen centers, and it is then continued to fill the interfibriller spaces in leather. Tannins combine with the positively charged –NH3+ of collagen of leather and eliminate the water according to the reactions. Lines 391to 406, highlighted in yellow.
Point 6. - the major concern is that this manuscript is more like investigation research, by extract and characterize tannin from 5 species. However the key core of this study was absence, which make it more like report not a research
Response 6: Conclusions were added to the document, lines 471 to 480, highlighted in yellow.
Author Response File: Author Response.docx
Round 2
Reviewer 2 Report
Accept
minor revision is recommended
