Conversion of Dry-Salted Cannonball Jellyfish (Stomolophus meleagris) Umbrella and Oral Arms to Cornmeal Snacks and Gelatin with Antioxidant Properties

Round 1

Reviewer 1 Report

Regarding "preparation of cornmeal snacks", processing steps are only "mixing of flours with water" and "frying in corn oil" after preparation of dried jellyfish flours. However, there is no discussion about effect of these steps on changes of each evaluations (chemical composition, antioxidant properties etc.). If description is limited to introducing each values and their significance without speculation of its mechanism, this manuscript should not be accepted as research article. Additionally, sensory analysis was only for preferences (no statement of  textural properties). In conclusion, statement of this section seems to be quality check report level by food industry. 

For "preparation and analysis of gelatin powder", it's lacking gelatin purity data (it can be evaluated by determination of Hyp content and AA composition of major collagen or gelatin molecular species). Authors refers their own publication [27] which analyzed their factors. However, instead of these conventional approach, ¹H-NMR was applied to evaluate characteristics of protein form amino acids. The reason (effectiveness should be described). In addition, no clear evidence of "These results coincide with other studies [27]... (line 291)". 

Author Response

Reviewer: 1

Thank you for your suggestions and comments.  In the main document, the substantive amendments are indicated in blue.  We respond to each comment in the following paragraphs:

Regarding "preparation of cornmeal snacks", processing steps are only "mixing of flours with water" and "frying in corn oil" after preparation of dried jellyfish flours. However, there is no discussion about effect of these steps on changes of each evaluations (chemical composition, antioxidant properties etc.). If description is limited to introducing each values and their significance without speculation of its mechanism, this manuscript should not be accepted as research article. Additionally, sensory analysis was only for preferences (no statement of  textural properties). In conclusion, statement of this section seems to be quality check report level by food industry.

Answer: Thank you for your suggestion. We agree with you. Regarding "preparation of cornmeal snacks", in the methodology section we add more information (please see L87 to L93) and the results were included and discussed (please see Table 1 and L222 to L251). Concerning the sensory analysis, we add more details about this evaluation (please see L130 to L150), and the results were discussed based on these details (please see L299 to L308).

For "preparation and analysis of gelatin powder", it's lacking gelatin purity data (it can be evaluated by determination of Hyp content and AA composition of major collagen or gelatin molecular species). Authors refers their own publication [27] which analyzed their factors. However, instead of these conventional approach, 1H-NMR was applied to evaluate characteristics of protein form amino acids. The reason (effectiveness should be described). In addition, no clear evidence of "These results coincide with other studies [27]... (line 291)".

Answer: Thank you for your observation. We agree with you. Regarding the Hyp content, in the methodology section we add the analysis of proline and hydroxyproline (please see L168 to L177) and the results were included and discussed (please see Table 4 and L346 to L355). Concerning the 1H-NMR, the discussion of the results was modified (please see L2371 to L383).

Reviewer 2 Report

In this manuscript, the authors convert dry-salted brown cannonball jellyfish umbrella and oral arms to cornmeal snacks and gelatin with antioxidant properties. This manuscript is interesting; however, more specific info is necessary to determine the originality of this finding. Is this finding the first time that cannonball jellyfish umbrella (UM) and oral arms (OA) are applied to prepare cornmeal snacks and gelatin with antioxidant properties? If so, should the authors provide specific evidence or if not, what are the differences from other reports currently in public literature (relevant references require to include)?

The authors used SDS-PAGE to purify the umbrella and oral arms but the details of sample preparation for SDS-PAGE analysis are not provided in the text.

The discussion is poorly written. A cutting-edge discussion with relevant references is essential to include in the manuscript to justify the current study. 

 

Author Response

Reviewer: 2

Thank you for your suggestions and comments.  In the main document, the substantive amendments are indicated in blue.  We respond to each comment in the following paragraphs:

In this manuscript, the authors convert dry-salted brown cannonball jellyfish umbrella and oral arms to cornmeal snacks and gelatin with antioxidant properties. This manuscript is interesting; however, more specific info is necessary to determine the originality of this finding. Is this finding the first time that cannonball jellyfish umbrella (UM) and oral arms (OA) are applied to prepare cornmeal snacks and gelatin with antioxidant properties? If so, should the authors provide specific evidence or if not, what are the differences from other reports currently in public literature (relevant references require to include)?

Answer: Thank you for your suggestion. We agree with you. In the introduction section, we add more information to justify this work (please see L39 to 48; L63 to 68); also, we rewrite the objective (please see L72 to 78), and more references were included, please see the references section. We hope the changes made in the introduction section improve its quality.

The authors used SDS-PAGE to purify the umbrella and oral arms but the details of sample preparation for SDS-PAGE analysis are not provided in the text.

Answer: Thank you for your observation. Sorry for the confusion, we did not purify the obtained gelatin, we use the SDS-PAGE to obtain the protein pattern of jellyfish gelatin. We rewrite this section (please see L178 to L183).  

The discussion is poorly written. A cutting-edge discussion with relevant references is essential to include in the manuscript to justify the current study.

Answer: We thank the reviewer for pointing this out. We rewrite completely section 3 adding relevant references (please see from L222 to L424). We hope the changes made in the results section improve its quality.

Reviewer 3 Report

Dear Authors,

Your manuscript on converting dry-salted cannonball jellyfish into cornmeal snacks and gelatin preparation with antioxidant properties is timely and interesting. It's a comprehensive study with clear applicable aims.

I suggest to modify introduction lines 61-66 to avoid repetition and express the main aims more clearly. For the discussion, I suggest to add some more references and information, what are the compounds producing the antioxidant effect. 

Author Response

Reviewer: 3

Your manuscript on converting dry-salted cannonball jellyfish into cornmeal snacks and gelatin preparation with antioxidant properties is timely and interesting. It's a comprehensive study with clear applicable aims.

Thank you for your suggestions and comments.  In the main document, the substantive amendments are indicated in blue.  We respond to each comment in the following paragraphs:

I suggest to modify introduction lines 61-66 to avoid repetition and express the main aims more clearly.

Answer: Thank you for your suggestion. We agree with you. We rewrite the objective (please see L72 to 78).

For the discussion, I suggest to add some more references and information, what are the compounds producing the antioxidant effect.

Answer: We thank the reviewer for pointing this out. We rewrite completely section 3 adding relevant references (please see from L222 to L424). We hope the changes made in the results section improve its quality.

Round 2

Reviewer 1 Report

Background and importance of jellyfish resource and its development was revised. However, there are several problem regarding research design and discussion.

Representative ones are listed below:

1. 40 unbrella and 40 oral arms are treated and finally combined separately. It means standard deviation of Table 1 means only experimental variation, so variation by drying and other process can not be evaluated. Therefore, discussion should be limited only on specific lots that authors prepared in this research.

 

2. 1H-NMR was conducted for dissolved gelatin without hydrolysis, but there is no discussion of gelatin structure. The authors added determination of Pro and Hyp values determined by amino acid analysis (discussed them between l346 and l354. To discuss other amino acid molecules (like l375-l382), chromatogram of this AA analysis should be used. 
In addition, Pro and Hyp is expressed as mg/100g, but this "100g" is not clear, gelatin powder weight or total protein in gelatin powder computed.

 

Author Response

Thank you for your suggestions and comments.  In the main document, the substantive amendments are indicated in blue. We respond to each comment in the following paragraphs:

Comments to Authors:

• Background and importance of jellyfish resource and its development was revised. However, there are several problem regarding research design and discussion.

ANSWER: We, the authors, are very glad you appreciated our work. Your comments and suggestions mean a lot to us. We tried our best to clarify the points you kindly pointed out.

 

• 40 unbrella and 40 oral arms are treated and finally combined separately. It means standard deviation of Table 1 means only experimental variation, so variation by drying and other process can not be evaluated. Therefore, discussion should be limited only on specific lots that authors prepared in this research.

ANSWER: Thank you for your comments. Using your kind observations, we modified the following paragraphs.

• Lines 227-230, page 5. The knowledge of original composition of any sample is considered critical in the development of any particular food, especially one with functional attributes [11]. As expected, dry-salted umbrella and oral arms had a high content of ash (Table 1). The ash value was significantly higher (p < 0.05) in the umbrella compared with oral arms.

 

• 1H-NMR was conducted for dissolved gelatin without hydrolysis, but there is no discussion of gelatin structure.

 

ANSWER: We agree with your comments. While NRM helped with the partial elucidation of the protein structure, more information was added in order to further establish the nature of the proteins in the samples.

• Lines 379-387. The 1H-NMR analysis of umbrella and oral arms gelatin indicated the presence of water molecules (4.8 ppm), proline (4.47 ppm), histidine (3.1), imino amino acid group of hydroxymerodesmosine (HMD) (3.8 ppm), glutamate (2.1 ppm), isoleucine (1.8 ppm), threonine (1.2 ppm), and lysine (0.7 ppm) according to literature data [46]. Proton alpha-Pro and protons present in HMD chemical displacements were similar in both samples. However, the intensity of this peak varied. More intense peaks were observed in gelatin from in oral arms than in umbrella. These observations are consistent with the above discussed Pro and Hyp content. In addition, the NMR results further help with the partial characterization of the proteins present in the jellyfish samples.

 

• The authors added determination of Pro and Hyp values determined by amino acid analysis (discussed them between l346 and l354. To discuss other amino acid molecules (like l375-l382), chromatogram of this AA analysis should be used.

 

ANSWER: We agree with the reviewer. Information has been modified in order to clarify this point.

• Lines 350-360, page 9. The analysis of the total imino acid (Proline, Pro + hydroxyproline, Hyp) revealed that, gelatin from oral arms had a higher (p < 0.05) Hyp content than umbrella (Table 3). Unlike to Hyp content, no significant differences (p> 0.05) was observed between Pro content of umbrella and oral arms. It is known that glycine, proline and hydroxyproline are the most abundant amino acids found in gelatin composition, but their values depend on the source, as imino acids participated in hydrogen bonds formation [43]. Total amount of imino acids (proline and hydroxyproline) of both anatomical regions are comparable to umbrella of desalted jellyfish (Lobonema smithii) gelatin (30 mg/100 g protein) and the content of oral arms was 40 mg/100 g protein [44]. Under the conditions of this study, this result indicated that the collagen tissue derived from oral arms, possessed a higher degree of crosslinks than umbrella. This behaviour was confirmed by SDS-PAGE.

 

• In addition, Pro and Hyp is expressed as mg/100g, but this "100g" is not clear, gelatin powder weight or total protein in gelatin powder computed.

ANSWER: We apologize for this mistake. It has been modified in the main text.  

• Lines 357-358, page 9. to umbrella of desalted jellyfish (Lobonema smithii) gelatin (30 mg/100 g protein) and the content of oral arms was 40 mg/100 g protein [44].

Reviewer 2 Report

N/A

Author Response

We thank the reviewer for your observations concerning to English language and style are fine/minor spell check required, then the manuscript has been extensively reviewed by an English-language proficient person