Microbial Exopolysaccharides in Traditional Mexican Fermented Beverages

Round 1

Reviewer 1 Report

The manuscript refers to traditionally fermented beverages especially in their physicochemical properties, the microorganism performing fermentation as well as their manufacturing technologies. The production of EPS in the majority of cases is linked to the specific fermented beverage through the specific microorganisms (mainly LAB bacteria) that perform the fermentation. The manuscript is well written and could be qualified for publication in Fermentation.

Some minor comments

The authors should check the manuscript for spelling errors for instance sacarose should be replaced by saccharose or sucrose.

The title should contain the words traditional and regional since  the beverages reported are not common bevarages. The title could be “Technofunctional properties of exopolysaccharides in traditionally fermented regional beverages”

Author Response

Some minor comments

The authors should check the manuscript for spelling errors for instance sacarose should be replaced by saccharose or sucrose.

R= Spelling errors have been checked

The title should contain the words traditional and regional since the beverages reported are not common beverages. The title could be “Technofunctional properties of exopolysaccharides in traditionally fermented regional beverages”

R= The title have been change from “Technofunctional properties of exopolysaccharides in fermented beverages” to “Microbial exopolysaccharides in traditional Mexican fermented beverages”

Reviewer 2 Report

Pages 4-12 need to be consolidated. There is no need for an extensive description of the process of each beverage when the focus of the paper is supposed to be on EPS. Authors should focus more on the role of EPS in each of these beverages. 

Not sure why sections 4 and 5 are at the end of the paper. They should be moved to the introduction and need to be consolidated. The focus of the paper should be on EPS.

Author Response

Pages 4-12 need to be consolidated. There is no need for an extensive description of the process of each beverage when the focus of the paper is supposed to be on EPS. Authors should focus more on the role of EPS in each of these beverages. 

R= Pages 4-12 have been modified. We delete sections “3.11 Physicochemical properties”, “3.1.2. Microbiota”, “3.2.1. Physicochemical properties”, “3.2.2. Microbiota”, “3.3.1. Physicochemical properties”, “3.3.2. Microbiota”, “3.4.1. Physicochemical properties” and “3.4.2. Microbiota”. Only the most relevant information in each fermented beverage has been described. Also, sections “3.1.3. Manufacturing technologies”, “3.2.3. Manufacturing technologies” and “3.3.3. Manufacturing technologies” have been deleted since they did not provide essential information in this article.

Not sure why sections 4 and 5 are at the end of the paper. They should be moved to the introduction and need to be consolidated. The focus of the paper should be on EPS.

R= We decided to not move these sections, in order to close/conclude the document, once it has been modified.

Reviewer 3 Report

As the title suggests, the review has to be focused on the exopolysaccharides presented in fermented beverages. The abstract and introduction sections revealed that the review should refer primarily to EPSs produced by LAB. However, in the next section (3. Traditionally fermented regional beverages), a lot of physicochemical, microbiological and production characteristics of four regional beverages are considered, as EPSs and LAB are almost not mentioned. It seems that only one of the listed beverages (Aguamiel) contains organisms, producing EPSs. Sections 4, 5 and 6 again refer to EPSs and EPSs producing LAB, but here they are related to quite different fermented products. It seems that there is no clear connection between the different parts of the paper. If the authors claim that EPS in the described beverages are produced predominantly by the lactic acid bacteria in their content, studies about EPS of LAB isolated from these beverages should be referenced.

Minor remarks:

The authors should use the new taxonomy of Lactobacilaceae family, acquired by the scientific community in 2020 (Zheng et al., 2020), https://www.wincloveprobiotics.com/sites/default/files/downloads/zheng_2020_-_a_taxonomic_note_on_the_genus_lactobacillus.pdf,

Line 33 – incorrect reference (79),

Figure 1: Maybe authors mean “inulin-type” instead of “insulin-type”,

Line 98: Specify the enzyme (“an enzyme”),

Lines 104 and 182 – Contradiction - aculeata or aculata,

Table 1 “This is a table shows” should be rewritten,

Lines 200, 240, 294 – add year or ref. number to the reference.

In conclusion, authors may decide first what exactly the review should be about – about EPSs (producing by LAB or any), or about the healthy characteristics of the traditional regional beverages. The relationship between them is not clearly shown in the present submission.

Author Response

Comments and Suggestions for Authors

As the title suggests, the review has to be focused on the exopolysaccharides presented in fermented beverages. The abstract and introduction sections revealed that the review should refer primarily to EPSs produced by LAB. However, in the next section (3. Traditionally fermented regional beverages), a lot of physicochemical, microbiological and production characteristics of four regional beverages are considered, as EPSs and LAB are almost not mentioned. It seems that only one of the listed beverages (Aguamiel) contains organisms, producing EPSs. Sections 4, 5 and 6 again refer to EPSs and EPSs producing LAB, but here they are related to quite different fermented products. It seems that there is no clear connection between the different parts of the paper. If the authors claim that EPS in the described beverages are produced predominantly by the lactic acid bacteria in their content, studies about EPS of LAB isolated from these beverages should be referenced.

R= According to the reviewers' comments, the document has been structured to show a clearer relationship between the EPS present in the different traditional fermented beverages and the microorganisms present in the process. Pages 4 to 21 involve these modifications

Minor remarks:

The authors should use the new taxonomy of Lactobacilaceae family, acquired by the scientific community in 2020 (Zheng et al., 2020), https://www.wincloveprobiotics.com/sites/default/files/downloads/zheng_2020_-_a_taxonomic_note_on_the_genus_lactobacillus.pdf,

R= Taxonomy for this microorganism and others has been changed in the manuscript:

Arthroascus spp

Hanseniaspora uctum

Kloeckera spp

Lactobacillus fementum

Liquorilactobacillus sucicola

Lactiplantibacillus plantarum

Bradysia difformis

Line 33 – incorrect reference (79),

R= reference number have been corrected.

Figure 1: Maybe authors mean “inulin-type” instead of “insulin-type”

R= Text in Figure 1 have been changed from “insulin-type” to “inulin-type”

Line 98: Specify the enzyme (“an enzyme”),

R= this line could not be modified due to it have not been detailed in the article.

10. Xu et al., “Exopolysaccharides produced by lactic acid bacteria and Bifidobacteria: Structures, physiochemical functions and applications in the food industry,” Food Hydrocoll., vol. 94, no. July 2018, pp. 475–499, 2019, doi: 10.1016/j.foodhyd.2019.03.032.

Subtitle “2.1. Biosynthesis and chemical classification EPSs” page 477.

However, the synthesis of EPS has been reestructured.

Lines 104 and 182 – Contradiction - aculeata or aculata,

R= these lines have been attended and changed to aculeata.

Table 1 “This is a table shows” should be rewritten,

R= This have been changed from “This is a table shows” to “Species of the genera: Saccharomyces, Candida, Pichia, and Acetobacter present in tavern”

Lines 200, 240, 294 – add year or ref. number to the reference.

R= Year have been added to those lines. Moreover, the reference numbers is at the end of each paragraph.

Reviewer 4 Report

Overall, the title of the manuscript covers an important aspect; however, the manuscript lacks the objective and proper structure of a review article. Next, the manuscript requires proofreading to improve its clarity. Therefore, I have several concerns regarding this manuscript before recommending acceptance.

• The manuscript lacks objective and does not explain what will be reviewed in the manuscript.
• The authors focus on fermented regional beverages, their physicochemical properties, microbiota, manufacturing technologies but do not describe EPS present in detail.
• As per the title, the manuscript needs to focus on EPS rather than fermentation technologies.
• Figure 2 does provide a synopsis of how EPSs are synthesized. It should have further details.
• Not all LABs are GRAS. Therefore, a detailed explanation of safe and unsafe LABs is required here.

Author Response

Comments and Suggestions for Authors

Overall, the title of the manuscript covers an important aspect; however, the manuscript lacks the objective and proper structure of a review article. Next, the manuscript requires proofreading to improve its clarity. Therefore, I have several concerns regarding this manuscript before recommending acceptance.

• The manuscript lacks objective and does not explain what will be reviewed in the manuscript.
• The authors focus on fermented regional beverages, their physicochemical properties, microbiota, manufacturing technologies but do not describe EPS present in detail.

R= The manuscript has been restructured and also the abstract

Abstract: Exopolysaccharides (EPS) are metabolites produced by many microorganisms. These extracellular metabolites are responsible for conferring some specific characteristics to fermented products, such as modifying their organoleptic properties or conferring biological activities. EPS can be easily found in the dairy industry, where they confer rheological properties in products such as yogurt or cheese, among others. Over the years, LAB have been recognized as good starter strains in spontaneous fermentations, as they can contribute beneficial properties to the final product, in conjunction with yeasts. To our knowledge, several articles have reported that EPS produced by LAB and yeasts possess many both biological and technological properties that can be influenced by many factors in which fermentation occurs. Therefore, this review presents some traditional Mexican fermented beverages and relates them to the microbial EPS that can be found in them, which confer biological and techno-functional activities.

• As per the title, the manuscript needs to focus on EPS rather than fermentation technologies.

R= Title have been modified

• Figure 2 does provide a synopsis of how EPSs are synthesized. It should have further details.

R= Figure 2 has been changed to provide more details

• Not all LABs are GRAS. Therefore, a detailed explanation of safe and unsafe LABs is required here.

R= Lines 31-37 have been modified as follows: “In addition to their status, since a large number of species of this genera are considered with the tag of “Generally Recognized as Safe” (GRAS) according to the U.S. Food and Drug Administration (FDA), where we can find Carnobacterium, Lactococcus, Leuconostoc, Oenococcus, Pediococcus, Streptococcus and Lactobacillus genus, recently reclassified [2].LAB also play an important role in the improvement of physical properties of fermented food products, since . In fact, many of these enhancements have been attributed to the presence of exopolysaccharides (EPS) in LAB [3], [4], which contribute to the texture, mouthfeel perception and stability of fermented products [5], [6].

Round 2

Reviewer 3 Report

There is some improvement in the article, but it is far from enough to be published.
Most importantly, it is still not clear what exactly is considered in this review: all microbial EPSs or only those of lactic acid bacteria, which causes serious confusion in the reader. However, since a lot of information has been gathered about other bacterial species outside LAB, as well as yeast, I assume that all microbial producers of EPS are considered.
The main disadvantages of the text are the following:
The abstract does not match the content. It should show: (1) which are the traditional Mexican drinks that are considered in the review, (2) which are the microorganisms in them, and (3) what EPSs they produce. Instead, we see general talk about LAB and EPS, which does not provide any information on review content.
EPS can not be called "metabolites", please, use "biopolymers" or "glycans".

Another major drawback: many terms are used incorrectly, e.g. page 2, line 42 - pectin and gelatin are none of the three (fats, sugars, proteins) listed, line 69 - HEPS cannot be divided into these 3 types, etc.
Figure 1 - Many EPSs that are not produced microbially are presented, this should be edited.
Table 2 can not remain in this form! Specific examples should be given in the EPS column, rather than details of the bacteria that produce them. This column could be moved to the main text, and the table should return to normal dimensions, similar to Tables 1 and 3.

Please shorten Table 2 drastically, as it contains meaningless long descriptive texts that are completely unsuitable for a Table.

In Table 3, add column №1 - "Beverage" and the examples related to that specific beverage, instead of giving examples of bacteria isolated from other sources, such as kefir.
A serious drawback of the paper is the severely confused microbial taxonomy. Many species' names are still misspelled. The following are the correct: Limosilactobacillus fermentum, Lacticaseibacillus casei, Fructilactobacillus fructosus, Saccharomyces guilliermondii. I ask the authors to take the time to check all the names of microorganisms on the Internet, as many of them are wrong.
Section 4.1 is redundant. Sections 4 to 6 are devoted only to lactic acid bacteria. They can be combined in one section - "lactic acid bacteria and their influence on the functional qualities of traditional Mexican drinks". Then in this section, you can include everything you want, but let it be clear that it only applies to LAB.

However, the final words should take us back to all the microorganisms that produce EPS in traditional Mexican drinks, as this is the main thesis of the work - i.e. the last section should be revised.

The references are not arranged according to the requirements of the journal. Please, see in the recent papers how they have to appear: [5,6] instead [5], [6]; [7-9] instead [7]-[9], etc. The reference list is completely wrong, please refer to the journal's site. 
And finally, the article must be checked by a translator or an English-speaking colleague, as there are too many mistakes and illogical expressions.

Author Response

Thank you for the valuable comments on the manuscript, below is how they were addressed.

There is some improvement in the article, but it is far from enough to be published.
Most importantly, it is still not clear what exactly is considered in this review: all microbial EPSs or only those of lactic acid bacteria, which causes serious confusion in the reader. However, since a lot of information has been gathered about other bacterial species outside LAB, as well as yeast, I assume that all microbial producers of EPS are considered.

R= The introduction section has been modified so that it is clearer what the manuscript seeks to address. While more information is presented about EPS produced by LAB, EPs produced by other microorganisms are also of interest to the authors.

1. Introduction

Currently, a large amount of microorganisms such as bacteria, yeasts, fungi and algae are well known for producing exopolysaccharides (EPS); in nature, these biopolymers confers protection, adhesion and biofilm formation to the microorganism helping it to adapt and survive in the environment in which is proliferating. This biofilm consists of a population of microbial cells which exhibit better resistance against nutrient reduction, temperature, pH changes, effect of reactive by-products of oxygen (superoxide anion radical, among others), antiseptics and antibiotics in comparison to individual microbial cells [1,2]. EPS produced by microorganisms are important because of their functional and biological properties. Nevertheless, the EPS synthetized by lactic acid bacteria (LAB) are prominent within the food, cosmetic and pharmaceutical industry due to consumer demand [3], since a large number of species of this genera are considered with the tag of “Generally Recognized as Safe” (GRAS) according to the U.S. Food and Drug Administration (FDA), where we can find Carnobacterium, Lactococcus, Leuconostoc, Oenococcus, Pediococcus, Streptococcus and Lactobacillus genus, recently reclassified [4]. LAB’s EPS have been related with the improvement of physical properties of fermented food products, like the texture, mouthfeel perception and stability of fermented products [5,6].

For example, the commercial use of EPSs from LAB in the area of fermented dairy foods has conventionally been aimed at producing unique physical characteristics such as enhanced viscosity and water-binding; the result of this is that the consumer enjoys an improved "mouthfeel". Consumers have been attracted to smooth and creamy textures, which are conventionally achieved through the addition of fats, sugars and proteins such as glycan [7]. Several articles have reported EPS with potential health and nutritional benefits from LAB. These EPS have also been associated with different biological properties, such as anti-tumoral, anti-hypertensive, anti-ulcer, immunomodulating, or cholesterol-lowering activity [5,7].

Although the EPS produced by LAB have been considered by the literature as the most important, in this review it is not intended to focus only on them, but on all the microorganisms found within the fermentation process of each one of the traditional Mexican fermented beverages that are presented in this document and how some of these are related to their biological and technological properties."

The main disadvantages of the text are the following:
The abstract does not match the content. It should show: (1) which are the traditional Mexican drinks that are considered in the review, (2) which are the microorganisms in them, and (3) what EPSs they produce. Instead, we see general talk about LAB and EPS, which does not provide any information on review content.
EPS can not be called "metabolites", please, use "biopolymers" or "glycans".

R= Abstract was modified as follows:

"Abstract: Exopolysaccharides (EPS) are biopolymers produced by many microorganisms, including some species of the genus Acetobacter, Bacillus, fructobacillus, Leuconostoc, Lactobacillus, Lactiplantobacillus, Pediococcus, Pichia, Rhodotorula, saccharomycodes, Schizosaccharomyces and Sphingomonas, which have been reported in the microbiota of traditional fermented beverages. Dextran, levan, glucan, gellan and cellulose among others, are some EPS that have been found within these genera. Extracellular biopolymers are responsible for conferring some specific characteristics to fermented products, such as modifying their organoleptic properties or conferring biological activities. However, EPS can be easily found in the dairy industry, where they confer rheological properties in products such as yogurt or cheese, among others. Over the years, LAB have been recognized as good starter strains in spontaneous fermentations, as they can contribute beneficial properties to the final product, in conjunction with yeasts. To our knowledge, several articles have reported that EPS produced by LAB and yeasts possess many both biological and technological properties that can be influenced by many factors in which fermentation occurs. Therefore, this review presents some traditional Mexican fermented beverages (tavern, tuba, sotol and aguamiel) and relates them to the microbial EPS that can be found in them, which confer biological and techno-functional activities."

Another major drawback: many terms are used incorrectly, e.g. page 2, line 42 - pectin and gelatin are none of the three (fats, sugars, proteins) listed, line 69 - HEPS cannot be divided into these 3 types, etc.

R= Phrases were corrected

"HEPS are comprised of different varieties of monosaccharides, these being D-glucose, D-galactose, L-rhamnose, and their derivatives."

Figure 1 - Many EPSs that are not produced microbially are presented, this should be edited.

R= Figure 1 was edited

Table 2 can not remain in this form! Specific examples should be given in the EPS column, rather than details of the bacteria that produce them. This column could be moved to the main text, and the table should return to normal dimensions, similar to Tables 1 and 3.

R= Table 2 was corrected

In Table 3, add column №1 - "Beverage" and the examples related to that specific beverage, instead of giving examples of bacteria isolated from other sources, such as kefir.

R= Table 3 was corrected, however the suggested column "beverage" was not added. This is because the purpose of the Table 3 is to show punctually the EPS produced by each of the microorganisms presented, and not to establish a relationship of the microbiota with the beverage and EPS produced, because this is addressed in Table 2.

A serious drawback of the paper is the severely confused microbial taxonomy. Many species' names are still misspelled. The following are the correct: Limosilactobacillus fermentum, Lacticaseibacillus casei, Fructilactobacillus fructosus, Saccharomyces guilliermondii. I ask the authors to take the time to check all the names of microorganisms on the Internet, as many of them are wrong.

R= Microbial taxonomy was corrected

Section 4.1 is redundant. Sections 4 to 6 are devoted only to lactic acid bacteria. They can be combined in one section - "lactic acid bacteria and their influence on the functional qualities of traditional Mexican drinks". Then in this section, you can include everything you want, but let it be clear that it only applies to LAB.

R= Section 4-6 were combined and corrected as follows:

"4. Lactic acid bacteria and their influence on the functional qualities of traditional Mexican drinks

LABs have a long history as fermentation initiators, contributing to a higher rate of hygienic safety, storage stability, improved rheology, and attractive sensory properties [11]. However, the EPS produced by LAB are regularly used as thickeners, stabilizers, and gelling agents due to their unique physicochemical properties in the food industry. At the same time, in some investigations, it is considered as a sustainable agent since the absorption of heavy metals through the use of these polysaccharides has been reported [70].

In recent years, reported studies have shown that EPS confers potential benefits to making healthy products, maintaining stability in the gastrointestinal environment, and improving the colonization of other probiotics. Due to, EPS have tolerance to conditions that occur in the gastrointestinal tract (gastric acid and bile acids) which allows its permanence in the intestinal tract and the generation of short-chain fatty acids through the degradation of the colon [6,48]. The EPS that precede the LAB, also show several beneficial activities for health, the most apparent health attribute imparted by EPSs is that of reducing the inclusion of sugars and fats associated with obesity. However, it has another important attributes such as antioxidant activity, cholesterol level reduction, antimicrobial, antitumor, immunomodulation, antibiofilm and antidiabetic formation[71].Therefore, EPS from LAB could be used not only as a functional additive in food production, but also have great potential for application in the cosmetic and pharmaceutical industry due to their biological activities [71‒73].

Traditionally, when talking about probiotics, most people refer to dairy products such as yogurt or cheese; however, the high demand of vegetarian and/or lactose intolerant consumers in search of healthy products has given rise to the production of functional food. According to what was reported by Heo et al., apple is a representative fruit tested in various processed foods, whether in jam, juice or raw fruit. These had functional substances such as food fibers, vitamins and polyphenols, placing them as specific in improving antioxidants, anticancer, antidiabetics and good against cardiovascular diseases [74]. Given all the benefits that the apple can contribute, Heo et al.,  used this product as raw material for the elaboration of a fermented apple juice, where an isolated strain of a traditional fermented food from Korea is obtained: “Meju”. This strain, belonging to the LAB, was identified as L. plantarum [74]. The author used this LAB based on some of the bacteria of this genus are acidophilic and can proliferate in the low pH that apple juice presents. In addition, LAB have been reported as probiotic strains that promote health, as well as in the in the production of a variety of metabolites that improve taste and reduce malic acid. At the end of the experiment, it was shown that the fermentation process that was carried out with apple juice together with L. plantarum presented synergistic activity since this achievement increases antidiabetic activity by more than 200% and almost 40% in antioxidant activity, comparing the juice before and after fermentation. Heo et al., attribute antidiabetic activity to the presence of EPS since they can inhibit α-glucosidase [74]. Thus, they can reduce blood sugar and delay the absorption of carbohydrates. This was demonstrated since in the experiment producers and non-producers of EPS were used, being the producing strain in the presentation with the highest inhibitory activity [75].

On the other hand, Bancalari et al., worked on the elaboration of functional juices, from the direct fermentation of orange and celery juices through the use of LAB with a prebiotic effect. The use of juices from fruits and vegetables are good alternatives since they meet dietary requirements and improve cardiovascular health [76]. However, in order to obtain safe juices with a long shelf life, it is necessary to use procedures to stabilize them, the most frequent being thermal treatments. Otherwise, the use of these technologies affects the nutritional value that these drinks offer by degrading the micronutrients and decreasing the content of vitamin C, provitamin A and other nutritional factors such as antioxidants and phytochemicals [77]. The solution that these authors found was the use of lactic fermentation since it maintains or can even improve the nutritional and sensory properties of the product, the safety and shelf life. In addition to the fact that LABs are widely known for the great contribution of functional properties confer to fermented products, the presence of EPS is reported in the case of Lactobacillus casei strains, so it can confer probiotic activity to the product and thus obtain a functional drink.

Bancalari et al. [76] evaluated fifty strains of LAB isolated from different dairy products, 10 out of 50 strains were selected because they were able to grow in non-dairy products identifying among those ten strains as Lactobacillus casei, Lactobacillus rhamnosus, and Lactobacillus paracasei. The resistance to bile salts, acidification performance as well as its EPS production were evaluated. Each of these strains was evaluated with both juices (orange and celery). As a result, it was found that no strain was able to produce EPS in orange juice. On the other hand, in celery juice they presented good results, where L.rhamnosus strain showed the best values for EPS production. Nevertheless, it should be noted that L. casei and L. rhamnosus strains obtained a good fermentation in both juices, opening a new perspective for dairy isolated strains, as a starter in plant-derived juice fermentation, demonstrating the idea that adding probiotic strains to carry out the juice fermentation processes can be a good idea for obtaining a probiotic product, thus avoiding the use of heat treatments and maintaining its nutritional values [78‒81].

Equally important, Pérez-Cataluña et al. [82], talks about sour atole which is a Mexican acidic drink, this is a non-alcoholic drink and is derived from fermented corn. The sour atole is prepared by spontaneous fermentation for 24 h, and bacteria like LABs are commonly found at the end of this process. The author's objective was to analyze the microbial diversity present in this fermented drink, where strains from Pediococcus, Weisella, Lactobacillus, and Leuconostoc genera were found. Genera such as Enterobacteriaceae, Lactobacillaceae, Leuconostocaceae and Steptococcaceae with Acetobacteraceae for solid fermentation may be related to the high manual handling that the dough receives, while Enterobacteriaceae are found in the highest provide for the initial phase. LABs such as Lactobacillus are almost replaced after 12 h by the Streptococcus, Lactococcus and Weisella genera in liquid fermentation. On the other hand, in solid fermentation, the microorganisms that prevails throughout the whole process was Weisella, a dextran-producing homopolysaccharide, which helps to improve the rheology of the beverage. Spontaneous fermentation, as has been mentioned throughout this review, helps improve technological functions because they confer organoleptic properties, in many cases attributing it to the production of EPS. Besides, spontaneous fermentation helps to give functionality to the food due to all the biological activities that it can present thanks to the microbiota present during the entire process [83,84]."

However, the final words should take us back to all the microorganisms that produce EPS in traditional Mexican drinks, as this is the main thesis of the work - i.e. the last section should be revised.

R= Final remarks were corrected

"Final remarks

Some species present in the microbiota described for each traditional mexican beverage have demonstrated to be able to produce EPS, acording to reported literature [85,86]. These species were obtained through the fermentation process of each fermented beverage, it should be mentioned that most of them occur through a spontaneous fermentation where the proliferation of the microbiota present naturally is influenced by the geographical area in which the plant is located, factors like humidity, temperature, soil are important. Even so, the fauna and insects present in the area could interact with the fermentation process of the drink, providing different microorganisms which could contribute to other properties. The presence of these microorganisms results in a good source of beneficial effects to human health since it has been demonstrated that some EPS-producer strains possess biological effects such as antioxidant, prebiotic and inmmodulatory activity, among others. However, there exists several articles which report the use of EPS-producing LABs as starter strains, due to their technological properties, that can be exploited in the food industry, since they can avoid the use of certain treatments (physical and/or chemical) that are used to extend the shelf-life of product, like thickeners, stabilizers, and emulsifiers (this last one can also helps reducing the fat in food), with the plus that these can help maintain the nutritional properties of the products, without the need to subject them to sudden treatments that increase the loss of these. In particular, the organoleptic properties of some fermented beverages are related to the presence of EPS, for example, the viscosity texture in aguamiel is attribuited to the presence of dextran and levan polymers from Leuconostoc [1,51,87]."

The references are not arranged according to the requirements of the journal. Please, see in the recent papers how they have to appear: [5,6] instead [5], [6]; [7-9] instead [7]-[9], etc. The reference list is completely wrong, please refer to the journal's site. 

R= References were corrected

And finally, the article must be checked by a translator or an English-speaking colleague, as there are too many mistakes and illogical expressions.

R= The article was checked by an English-speaking colleague

Reviewer 4 Report

The authors did an excellent job revising the manuscript.

Author Response

Thank you for your feedback, which has allowed us to generate a higher quality manuscript.

Round 3

Reviewer 3 Report

The manuscript is substantially improved and is fully suitable for publication in its current form.

Some minor changes are needed before final publishing: Line 17: change "are some EPS found within these genera" to "are EPS produced by these genera".

Please, change the word "confer" with synonyms, as it is used 4 times in the abstract. For instance, Line 19: "conferring" change to "contributing to", line 20: "confer" change to "affect".

Figure 2 title: change "This figure explains the synthesis of EPS described by [16‒19]" to "Scheme of exopolysaccharides (EPS) synthesis"

All Tables contain the Table title below the table. Please, omit this, the Table title above the table is enough.

Lines 400-401, please, check the text and correct the words "Zymomonas" and "species".