The Effects of Different Postharvest Drying Temperatures on the Volatile Flavor Components and Non-Volatile Metabolites of Morchella sextelata
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsThe manuscript titled “Effects of different postharvest drying temperatures on the volatile flavor components and non-volatile metabolites of Morchella sextelata” has been reviewed.
The current study evaluated the effect of different drying temperatures on the volatile flavorr and non-flavour metabolites. The metabolomic data was collected.
General comments
In general, the study is feasible, and it does have an element of novelty. The document is well written, covered most the common robust methods that are used to characterise the metabolites. To highlight briefly:
- The background is well articulated, giving the importance of drying the true morels on postharvest quality, and sustainability of nutritional value.
- The problem statement is well captured, it is clear why this study was conducted.
- The M & M section is well written, however, there are few areas that need to be clarified. See the specific comments.
- Results and Discussion sections are well written.
- The conclusion is well articulated
Specific comments
M &M
L = Line
L79 – “The surface dust and other impurities were removed” – How were they removed?
Results and Discussion
The visuals are tiny, it is not possible to see the labels on x-axes and y-axes
This comment apply in all figures except Fig 1.
Comments on the Quality of English LanguageThe document is well written.
Author Response
Comments 1: L79 “The surface dust and other impurities were removed” – How were they removed?
Response 1: Thank you for pointing this out. We have added this information in Line 78-79 “The surface dust and other impurities were removed by hand shaking during harvesting.”
Comments 2: The visuals are tiny, it is not possible to see the labels on x-axes and y-axes. This comment apply in all figures except Fig 1.
Response 2: Thanks for the suggestion. The labels on the axes of all the figures have been enlarged and displayed in the form of vector graphs.
Reviewer 2 Report
Comments and Suggestions for AuthorsThe paper deals with the study of dehydration of the edible mushroom morhcella sextelata with emphasis on drying kinetics and flavor analysis.
The paper is interesting and well organized, however there are areas for improvement:
In the abstract the temperatures used could be included.
There is also no mention of the importance of volatiles present in the fungus and that would be lost during drying.
In l37 different drying rates are mentioned, but more than that they are conditions of the drying process that impact the kinetics of drying and sensitive compounds.
In l42 it is mentioned that hot air drying is cost effective and efficient, which, in comparison with other assisted drying processes, is not the case. It is recommended that this statement be revised, idem in l56.
It is important that the introduction clearly states the need to study volatiles, as it is written it is not clear.
Paragraph l67 to l74 needs to be reduced.
l77 Caliber or some other variable to standardize the experiments, category?
in l80 it talks about division in 15 portions, is there any detail about how they were divided? parts etc?
In which equipment the drying was performed, the air velocity and the bed density are not reported.
In l86 it is not specified with what equipment it was ground.
In some parts of materials and methods the equipment is not specified, it is necessary to review and standardize.
Throughout the document it is not clear how many repetitions were made for the different measurements/experiments.
L130 to l134 is not clear for what and how the conversion is performed.
Some of the software used is not adequately identified in relation to the versions of the programs.
In l162 there are two sets of soils? please review.
In reference to the results with the data you obtained you could easily calculate the drying rate, diffusivities and activation energy. On the other hand, it is recommended that the authors review more drying works so that they can improve this part. For example, drying curves are usually expressed in terms of dimensionless humidity and with decreasing curves.
There are some very small figures that do not allow a proper visualization of the data/results (fig 2, fig 5).
The conclusion can be improved in terms of the contribution to the discipline of food drying and preservation of edible mushrooms. In addition to its practical application
Author Response
Comments 1: In the abstract the temperatures used could be included.
Response 1: Thanks for the suggestion. Temperature information has been added to the abstract. See details in Lines 17-18.
Comments 2: There is also no mention of the importance of volatiles present in the fungus and that would be lost during drying.
Response 2: Thank you for pointing this out. The fruiting bodies of edible fungi are rich in soluble sugars, polyols, free amino acids, 5'-nucleotides and organic acids, which give edible fungi an attractive taste and flavor. Different postharvest drying techniques have different effects on the drying kinetics and physicochemical properties of mushrooms, resulting in differences in flavor and nutritional components. It's not only the loss of flavor. This information has been added in Lines 35-38.
Comments 3: In l37 different drying rates are mentioned, but more than that they are conditions of the drying process that impact the kinetics of drying and sensitive compounds.
Response 3: Thank you for pointing this out. Different postharvest drying techniques have different effects on the drying kinetics and physicochemical properties of mushrooms, resulting in differences in flavor and nutritional components. It's not only the loss of flavor. This information has been added in Lines 37-38.
Comments 4: In l42 it is mentioned that hot air drying is cost effective and efficient, which, in comparison with other assisted drying processes, is not the case. It is recommended that this statement be revised, idem in l56.
Response 4: Thank you for pointing this out. This description has been revised to “Hot air drying technology is suitable for drying large quantities of edible fungi and has been widely employed in the industry” in Lines 42-43 and “Hot air dryers are the preferred type of drying equipment among morel mushroom growers, especially for large-scale growers” in Lines 55-57.
Comments 5: It is important that the introduction clearly states the need to study volatiles, as it is written it is not clear.
Response 5: Thanks for the suggestion. True morels (Morchella spp.) are valuable edible mushrooms that are renowned for their unique aroma and taste. Hot air drying promotes the formation of heterocyclic compounds and ketones through thermal reactions in morels, resulting in the flavor and taste of dried morels different from fresh morels. However, the impact of different drying temperatures on the flavor and nutritional components of morel mushrooms, which are key consumer preference indicators, remains unclear. This information have been added in Lines 45-46 and Lines 59-62.
Comments 6: Paragraph l67 to l74 needs to be reduced.
Response 6: Thanks for the suggestion. This paragraph has been reduced to “The differences in the volatile flavor components and non-volatile metabolic components of dried morel mushrooms produced at various drying temperatures were analyzed using gas chromatography–ion mobility spectrometry (GC–IMS) and liquid chromatography–tandem mass spectrometry (LC-MS/MS), respectively. This provides theoretical support for establishing a standardized morel mushroom postharvest drying process.” See details in Lines 68-73.
Comments 7: l77 Caliber or some other variable to standardize the experiments, category?
Response 7: Thanks for the suggestion. Fresh morels (M. sextelata) with an ascocarp length of 9-11 cm, free from pests and diseases, and exhibited plump shapes were harvested from a farm located in Yangma Town (30.4°N, 104.5°E), Chengdu, China. This information has been added in Lines 76-77.
Comments 8: In l80 it talks about division in 15 portions, is there any detail about how they were divided? parts etc?
Response 8: Thanks for the suggestion. The harvested morels were divided into 15 portions weighing 1 kg each. A total of three treatments were set, with five replicates per treatment. Three different drying temperature treatments were set: 45°C (low temperature, LT), 55°C (medium temperature, MT), and 65°C (high temperature, HT). This information has been added in Lines 80-83.
Comments 9: In which equipment the drying was performed, the air velocity and the bed density are not reported.
Response 9: Thank you for pointing this out. The samples were dried in Electro-thermostatic blast oven (101–2-BS-II, Yuejin Medical Apparatus Factory, Shanghai, China) with the air velocity of 0.45m/s and the bed density of 0.44g/cm2.This formation has been added in Line 83-86.
Comments 10: In l86 it is not specified with what equipment it was ground.
Response 10: Thank you for pointing this out. The samples were ground were using a food processer (TW100, Beijing Grinder Instrument Co., Ltd., Beijing, China). This formation has been added in Lines 83-86.
Comments 11: In some parts of materials and methods the equipment is not specified, it is necessary to review and standardize.
Response 11: Thank you for pointing this out. The equipment in the Materials and Methods section has been standardized with highlighted in yellow.
Comments 12: Throughout the document it is not clear how many repetitions were made for the different measurements/experiments.
Response 12: Thank you for pointing this out. A total of three treatments were set, with five replicates per treatment. This formation has been added in Lines 81-82.
Comments 13: L130 to l134 is not clear for what and how the conversion is performed.
Response 13: Thank you for pointing this out. We have revised this part as “The raw mass spectrometry (MS) data were acquired using Xcalibur 4.1 software on the Q-Exactive instrument (Thermo Scientific). Subsequent processing was conducted using Progenesis QI software (Waters Corporation, Milford, USA) for data preprocessing, which included peak detection, extraction, alignment, normalization, and integration. Metabolite information was matched against both a local database and commercial databases (https://www. hmdb.ca/, https://metlin.scripps.edu/). After this preprocessing, an assessment was made: if more than 70% of the potential peaks in the QC samples had a relative standard deviation (RSD) of less than 30%, it indicated that the detection system was robustly stable and confirmed the reliability of the generated data”. See details in Lines 132-140.
Comments 14: Some of the software used is not adequately identified in relation to the versions of the programs.
Response 14: Thank you for pointing this out. The analysis of variance (ANOVA) was performed for comparisons among three treatments using PASW Statistics version 22 software (IBM SPSS Inc., Chicago, IL, USA). This formation has been revised in Lines 163-164.
Comments 15: In l162 there are two sets of soils? please review.
Response 15: Thank you for pointing this out. It was our negligence that led to this obvious mistake. And it has been revised as “The analysis of variance (ANOVA) was performed for comparisons among three treatments using PASW Statistics version 22 software (IBM SPSS Inc., Chicago, IL, USA).” See details in Lines 163-164.
Comments 16: In reference to the results with the data you obtained you could easily calculate the drying rate, diffusivities and activation energy. On the other hand, it is recommended that the authors review more drying works so that they can improve this part. For example, drying curves are usually expressed in terms of dimensionless humidity and with decreasing curves.
Response 16: Thank you for pointing this out. We adjusted the expression of the drying curve. See details in Figure 1. The corresponding text revisions were also highlighted in yellow in the Results and Discussion section. See details in Lines 171-173.
Comments 17: There are some very small figures that do not allow a proper visualization of the data/results (fig 2, fig 5).
Response 17: Thanks for the suggestion. The labels on Figure 2 and Figure 5 have been enlarged and displayed in the form of vector graphs.
Comments 18: The conclusion can be improved in terms of the contribution to the discipline of food drying and preservation of edible mushrooms. In addition to its practical application
Response 18: This study found that morels dried at different temperatures exhibited unique characteristics in terms of their volatile flavor components. It provides guidance for optimizing the drying technique of mushrooms after harvest. However, The standardized postharvest drying processes for morels can be optimized on the basis of this temperature in the future. The conclusion has been revised, see details in Line 308-309.
Round 2
Reviewer 2 Report
Comments and Suggestions for AuthorsI have revised the new version of the article and it has improved considerably. The only thing that should be improved is figure 1, they should represent the dimensionless moisture (moisture rate MR) and add error bars for each of the points.
Author Response
Comment 1: The only thing that should be improved is figure 1, they should represent the dimensionless moisture (moisture rate MR) and add error bars for each of the points.
Response 1: Thanks for this careful review. Figure 1 has been represented by moisture ratio (MR), and error bars have been added for each point. The corresponding text has also been revised. See details in Lines 90-93 and 174-175.
