Gluten-Free Brewing: Issues and Perspectives

Round 1

Reviewer 1 Report

This is a well written manuscript on gluten-free brewing. I did not see any problem in the manuscript.

only one thing

l254 in order to activate alpha amylase II-4 isoform reference needed

Author Response

"Please see the attachment"

Author Response File: Author Response.docx

Reviewer 2 Report

The authors proposed a detailed review of the existing strategies to produce gluten-free beers

-) In my opinion, it is always better, in case of a review paper, to find some references of the authors in order to understand how authoritative is the review. At least in the introductory parts, I suggest you to cite a few references from your team demonstrating that you have considerable expertise in the field.

-) Too often you started a new sub-paragraph (e.g. in the section 2., lines: 77, 86, 101, 106, 111). In this way, the writing appears fragmentary. Please revise the whole manuscript avoiding this style.

-) Punctual revisions up to the section 4 (minor points) underlined the need a further critical reading of the manuscript. Please also revise the rest of the manuscript. I would be please do revise the resting parts in the next round of revisions.

Line 17: This review aims to provide

Line 22: A survey on 185 GF-producing breweries (both industrial and craft)

Line 29: Beer is one of the most ancient and consumed beverages worldwide (https://www.mdpi.com/2306-5710/5/3/51/htm).

Line 31: each gives its indications

Line 34: ingredient for beer only later [1], but specific starter cultures are included in the product specification of traditional beers such as ‘Münchener Bier’ (https://www.sciencedirect.com/science/article/abs/pii/S0172219012000555).

Line 41: “increased in the last years”…you already talk of growth in the recent years…please eliminate and rewrite

Line 43: organic ingredients and free from GMO, since

Line 44: avoiding undesired chemicals

Line 46: aspect, artisanal products, and by a

Line 47: gluten-free (GF) beers

Line 48: but also drank by consumer

Line 49: It is just

Line 49: Common beer is not

Line 55: Mucosal negative changes

Line 56: did not show

Line 56: Thus, the value

Line 64: for example, Stout

Line 70: has different sensory attributes and a higher cost than conventional beer (ref needed). https://www.sciencedirect.com/science/article/abs/pii/S092422441400003X ?

Line 83: Also,

Line 93: gastroesophageal reflux

Line 98: anti-tissue

Line 107: for example, vitamin

Line 108: These macro- and micro-nutrients

Line 109: , GF cereals

Line 117: is essential to guarantee

Line 123: However, this technique

Line 127: In these cases,

Line 131: expensive equipment and expertise

Line 136: Also, Tanner

Line 137: near-zero gluten 

Line 139: Besides, DNA-based

Line 142: real-time PCR

Line 143: Given the above

Line 145: the matrix

Line 148: it does not contain

Line 149: example, triticale

Line 150: to remain under the level

Line 163: GF products trade

Line 167: portfolio. Nevertheless, higher

Line 170: as a case study

Line 179: “Most of the 46 Italian GF beers reviewed on web are craft.”…what about this survey…are you anticipating the survey reported at line 187? Please clarify…

Line 180: on the web are

Line 170-183: this long part on the Italian situation has to be adequately introduced/justified…please modify

Line 187: how did you select this list of 185 breweries? Randomly, with given criteria…please specify…

Author Response

"Please see the attachment"

Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

-) Please, where appropriate in the manuscript, discuss also the following articles:

https://www.mdpi.com/2311-5637/4/4/103

https://www.mdpi.com/1420-3049/24/8/1568/htm (especially the final part of the second section)

Line 199: in the final beer

Line 220: labelled

Line 222: <20 ppm, too (https://www.mdpi.com/2076-3271/4/4/21/htm).

Line 222: This cereal has a lower

Line 227: Nevertheless, also

Line 229: unsaturated fatty

Line 242: in the world

Line 243: Poaceae family

Line 245: process,

Line 257: unsaturated

Line 264: flat sensory characteristics (ref needed).

Line 268: in the brewing

Line 269: Besides, the prize of

Line 284: as a source

Line 287: Poaceae

Line 304: Africa, both as malted sorghum and as adjunct (https://www.mdpi.com/1420-3049/23/5/1203, https://www.mdpi.com/2306-5710/3/3/43).

Line 306: literature (ref needed)

Line 310: a high

Line 311: a relevant content

Line 313: the brewing

Line 330: Usually,

Line 331: it is difficulty in managing.

Line 338: a positive

Line 344: Brettanomyces

Line 346: than? Please verify the meaning

Line 346: more similar than barley (ref needed). Please verify that what reported in the reference coincides with what you reported in the sentence.

Line 349: Besides, millet

Line 354: to compensate for this

Line 385: in the brewing

Line 394: a possible

Line 403: a high

Line 405: in the final product

Lines 405-6: “Brewing characteristics of amaranth are not yet well known” it seems a repetition of what you reported at line

Line 412: as a substitute

Line 420: of the final

Line 423: from a plurality

Line 429: of the final

Line 453: Nevertheless, Taylor

Line 456: A. oryzae

Line 456: in the food

Line 461: Also, lactic acid bacteria (LAB)

Line 463: use in brewing [112]. However, tailored solutions can be transferred from the sourdough technology (https://www.mdpi.com/2304-8158/5/3/65/htm), as already done for other cereal-based products such as pasta (https://www.frontiersin.org/articles/10.3389/fmicb.2012.00094/full).  PEP from Sphaerobacter

Line 469: in the food industry

Line 474: in Europe, the

Line 476: However, they

Line 481: the extraction of the following enzyme

Line 484: could also be

Line 487: for example,

-) among the different strategies you propose, could be interesting introduce the fact that some are promising for Celiac Disease other for Gluten sensitivity, as it is the case (probably) of the precipitation treatment. Probably the best place for this part could be the introduction of section 5. (lines 196-203).

Line 500: a great

Line 503: filtration, but,

Line 519: of the final beer

Line 545: nevertheless, it allows

Line 547: evaluation is challenging.

Line 554: yoghurt-like flavour

Line 556: off-flavours

Line 558: generally has

Line 561: unsaturated

Line 564: relatively low

Line 584: the conventional one

Line 587: for example,

Lines 587-88: I suggest you to move this part on the microorganisms to the next section

Line 589: the conventional product.

Lines 595-96: “because of a low amount of  important aroma compounds produced  [129]. They are  bitter, probably because of  bitter-tasting  molecules,”…unclear…please rewrite…

Line 598: obtained a lower

Line 610: of the main disadvantages

Line 615: The other

Line 619: but unsuitable foam stability (ref needed). 

Line 621: the sample

Line 623: the sample

Line 628: In Table 4, 

Line 628: sensory  issues. The high number of variables to be monitored suggest the importance of a tailored analytical approach in order to screen diverse experimental modalities (e.g. https://www.ncbi.nlm.nih.gov/pubmed/28518086,https://www.sciencedirect.com/science/article/abs/pii/S0963996918304241).

Line 631: principal strengths and weaknesses

-) If I well understand, Table 4 includes strengths and weaknesses not only related to sensory properties. Giving the general nature of the table, I suggest you to move it in the section. In effect it can be of help in concluding and in shaping future perspectives.

Line 635: the final beer

Line 636: is crucial for an efficient

Line 644: repitching

Line 656-59: Are you sure? Please provide references

Line 664: them to identify  

Line 679: challenge…challenge…

-) ‘Conclusions and future trends’ appeared confused. This is a crucial part of your work. Please summarize and clarify as much as possible

Author Response

Please see the attachment

Author Response File: Author Response.docx

Round 3

Reviewer 2 Report

The authors revised the manuscript according to my suggestion.