Effect of Alkaline Treatment on Characteristics of Bio-Calcium and Hydroxyapatite Powders Derived from Salmon Bone
, Soottawat Benjakul 1, Sittichoke Sinthusamran 1, Thanasak Sae-leaw 1, Nobuo Suzuki 2, Yoichiro Kitani 2 and Pornsatit Sookchoo 3,*
Round 1
Reviewer 1 Report
The article "Effect of alkaline treatment on characteristics of bio-calcium and hydroxyapatite powders derived from salmon bone" aims to evaluate the effect of alkaline treatment on the formation of bio-calcium, HAp and B-TCP from salmon bones.
The study is interesting and well organised. Nevertheless, some minor issues should be addressed before acceptance.
Hydroxyapatite is abbreviated as HAp in the introduction. However, authors omit this abreviation throughout the manuscript. If a word is abbreviated at first mention, its abbreviation should be used onwards in the text.
Check the abstract for Beta-tricalcium phosphate, the beta sign is missing.
In the materials and method section, please check the number sections, E.g. for "chemicals" the number section should be 2.1 Chemicals instead of 22.1 Chemicals. Moreover this section should be reviewed and expanded, as probably more chemicals have been used in all the experiments carried on by the authors (E.g. NaOH is not provided, whereas is after mention in the pretreatment of bones)
Although the experimental procedures followed for the pretreatment of bones (biuret method and hydroxyproline [refs. 13 and 14]), the preparation of bio-calcium and calcined bone [ref 15], moisture, fat and ash [ref 16], TBARS [ref 15], mean particle size, etc. have been previously reported by other authors, it would be advisable to briefly described the procedure performed. This would help the readers understanding.
In Tables 1 and 2 data should be provided in significant numbers, according to their sd. E.g. in Table 1: 4.82±0.07 should be given as 4.8±0.1 and 12.07±0.18 as 12.1±0.2, whereas 7.81±0.04 is fine. Please, check the rest of the data provided.
The same for Table 2, e.g. 26.53±3.49 should be given as 27±3. Please, check the rest of the data provided in this table.
Author Response
Please see the attachment.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
This manuscript described the synthesis of hydroxyapatite and its mixture of tricalcium phosphate from salmon bone. The authors investigated the influence of alkaline pre-treatment before calcination on the product and they suggested a practical approach to use of a by-product from salmon industry. However, the preparations of hydroxyapatite from natural sources including fish bones have been already reported by several previous literatures. The alkaline hydrolysis treatments were also tried to control the Ca/P ratio of the fish bones: e.g.
Mater. Sci. Eng. C, 62 (2016), pp. 183-189, Chem. Eng. J., 215–216 (2013), pp. 522-532, Biomed. Mater., 6 (2011), pp. 1-12
For the publication of this work, authors should highlight a novelty that differentiates itself from other articles.
In the text, the authors suggested that the alkaline pretreatment is an effective way to reach an optimum value of the Ca/P ratio; i. e. the ‘Bio-cal H’ showed the Ca/P ratio = 1.60, whereas the ‘Bio-cal A’ showed the Ca/P ratio = 1.66. Although the changes in organic component were analyzed (in Table 1), the reason why the content ratio of the elemental Ca is changed is still not clear because the protein, fat and hydroxyproline do not contain the phosphorous element.
Overall, I cannot recommend it for publication in this stage because of the lack of novelty and clarity.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
In the revised version, the authors have adequately addressed the issues that I pointed out in the previous review. Overall, the clarity of the manuscript has improved substantially. I think that the manuscript is now acceptable for publication in Applied Sciences.
Author Response
The author greatly appreciates the invaluable comments and suggestions from the reviewer which could help improving the quality of our manuscript. The author hopes the reviewer is staying safe and healthy during this difficult time.
