Post-Cutting Hot Water Treatment of Pepper Fruit: Impact on Quality During Short-Term Storage

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This study evaluates the effects of heat treatment conditions on the quality of fresh-cut peppers. While the manuscript is well-written, the depth of analysis and the level of innovation are somewhat limited. The reliance on visual indicators to assess the effects is potentially insufficient and may be unreliable. More objective, instrument-based measurements should be included to provide a more robust assessment.

For example, browning should be quantified using color parameters such as L*, a*, b*, the browning index, and ΔE, determined with a color meter.

Similarly, the assessment of softening should be further substantiated by data on the count and types of microorganisms present.

The study assesses various quality parameters such as softening, browning, rotting, and marketable value. However, does heat treatment affect the flavor of the product? This quality indicator should be included, as heat treatment commonly causes changes in flavor in fresh-cut produce, both during and after storage.

Finally, the storage time of different pepper varieties is observed to vary. The manuscript should address the reasons for these differences.

Author Response

Thank you very much for taking the time to review this manuscript. Please find the detailed responses below and the corresponding revisions/corrections highlighted/in track changes in the re-submitted files.   Reviewer's comments and authors' responses:

This study evaluates the effects of heat treatment conditions on the quality of fresh-cut peppers. While the manuscript is well-written, the depth of analysis and the level of innovation are somewhat limited. The reliance on visual indicators to assess the effects is potentially insufficient and may be unreliable. More objective, instrument-based measurements should be included to provide a more robust assessment.

1. For example, browning should be quantified using color parameters such as L*, a*, b*, the browning index, and ΔE, determined with a color meter.

 Measurements of L* a* b* color parameters would be very good evidence of differences in the discoloration of the cut surface of peppers, and this is a task to be performed in future tests on cut vegetables. In the presented research, assessments were made based on developed nine-point scales.

2. Similarly, the assessment of softening should be further substantiated by data on the count and types of microorganisms present.

 The microbial load was tested in previous tests (not published) with peppers cut but packed in perforated plastic bags. We were somewhat reassured that there was no Esherichia coli in any of the objects. After one day of storage, in general, the most total bacteria and mold and yeast were in the control samples. After 4 days of storage, an increase in the number of microorganisms was observed, and due to large differences between individual samples within one experimental object, differences between treatments could no longer be determined. In the study presented here, microbiological analyses were no longer performed.

 

3. The study assesses various quality parameters such as softening, browning, rotting, and marketable value. However, does heat treatment affect the flavor of the product? This quality indicator should be included, as heat treatment commonly causes changes in flavor in fresh-cut produce, both during and after storage.

 The taste of a food product is very important to achieve consumer acceptability. In the conducted research, the focus was on the appearance of the commodity and in further stages sensory evaluation should be carried out on taste, smell and other distinguishing features.

 

4. Finally, the storage time of different pepper varieties is observed to vary. The manuscript should address the reasons for these differences.

 

The storage time for both varieties was 6 days at cold temperatures (3, 5 and 8°C). Additional samples from both varieties after 1 and 2 days following 4 days at cold storage. In the tables with quality parameters, is lack of the results after 2 days at cold storage, because for the variety Yecla they were only “1” for softening and “9” for commercial value. In lines 176 -177 there is information that after two days there were no signs of deterioration in quality. In the case of ‘Blondy’ only control peppers, after 2 days at 8°C shown very little browning, which is written about in lines 233 -236.

In the tables with weight loss, there were the results after two days, because they have already been found.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The manuscript by Grzegorzewska and Machlańska evaluated hot water treatment on the quality and durability of two varieties of fresh-cut peppers at three storage temperatures. The manuscript provided very valuable information for the fresh-cut vegetable industry. In my opinion, the manuscript can be accepted after minor revision. Please see my comments to improve the manuscript.
Line 16, please introduce the size of the pepper sticks.
Line 23-24, all the keywords should be re-organized. 'fresh-cut pepper', 'hot water treatment' should be involved.
Line 38, why is Israel mentioned here? The fresh-cut vegetables were invented from there, or what?
Line 59, 'wk' should be revised to 'week'.
Line 98-99, please provide the basic quality parameters of initial peppers, such as firmness, SSC, etc. Deliver to the lab within how many hours?
Line 104, the control group was immersed in room temperature water or without any treatments at all?
Line 105, please provide more details on  
how water treatment, such as how deep the peppers are immersed in the hot water. How was the water mixed to make sure the heat was even?
Line 108, what was the speed of the fans? How was the criteria for peppers dried?
Line 116, what was the relative humidity of the storage?
Figures 3, 4, and 8 should have scales.

Author Response

Thank you very much for taking the time to review this manuscript. Please find the detailed responses below and the corresponding revisions/corrections highlighted/in track changes in the re-submitted files.   Reviewer's comments and authors' responses:

The manuscript by Grzegorzewska and Machlańska evaluated hot water treatment on the quality and durability of two varieties of fresh-cut peppers at three storage temperatures. The manuscript provided very valuable information for the fresh-cut vegetable industry. In my opinion, the manuscript can be accepted after minor revision. Please see my comments to improve the manuscript.

 

1. Line 16, please introduce the size of the pepper sticks.

 

Bell pepper fruits, after being cut in half and removing the placenta with seeds and inner sepals, were cut into strips 0.5-1.0 cm wide and equal in length to the length of the fruit. Information added, L: 103 – 105

 

2. Line 23-24, all the keywords should be re-organized. 'fresh-cut pepper', 'hot water treatment' should be involved.

 

Suggested words have been included in key words

 

3. Line 38, why is Israel mentioned here? The fresh-cut vegetables were invented from there, or what?

 

The Introduction section cites a report from the literature on the widespread practical use of HWT to treat whole fruits and vegetables, especially those being prepared for export shipment. We add in the text that “whole” fruit and vegetables.

 

4. Line 59, 'wk' should be revised to 'week'.

 

amendment has been made, L: 60

 

5. Line 98-99, please provide the basic quality parameters of initial peppers, such as firmness, SSC, etc. Deliver to the lab within how many hours?

 

The fruits purchased were freshly picked, firm and shiny. SSC was not measured. Deliver to lab took about 1.5. Information added, L: 101, 102

 

6. Line 104, the control group was immersed in room temperature water or without any treatments at all?

 

All whole fruits were washed, dried, then cut and divided into 5 groups. The control group was not treated with water. Information added, L: 109

 

7. Line 105, please provide more details on how water treatment, such as how deep the peppers are immersed in the hot water. How was the water mixed to make sure the heat was even?

 

The water temperature was measured all the time with two thermometers. While the water was being heated, two plastic openwork crates measuring 600 mm x 400 mm x 135 mm (L x W x H) were placed in a vessel and heated together with the water. Portions of cut peppers were placed in one crate and covered with another crate so that the sticks were completely submerged all the time (they did not float to the surface of the water). In a large volume of water (150 l), thermometers indicated an even temperature and no additional water mixing was performed. Information added, L: 113 – 119

 

8. Line 108, what was the speed of the fans? How was the criteria for peppers dried?

 

Immediately after treatment, the sticks were spread on 900 mm x 800 mm flat sieves. After draining the water, they were spread on other dry sieves lined with tissue paper. On these sieves, they were dried in a stream of air supplied by two SEVERIN VL 8620 fans, set to the lowest speed level (1 - low), until dry surfaces were obtained. Information added, L: 130 – 123

 

9. Line 116, what was the relative humidity of the storage?

 

The relative humidity in the storage room was 80 %. Trays of peppers in crates were covered with PE film to protect the peppers from wilting and drying out. Information added, L: 132

10. Figures 3, 4, and 8 should have scales.

 

The line scales were added to the figures.

 

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

I have reviewed the manuscript titled “The Post-Cutting Hot Water Treatment of Pepper Fruit: Impact on Quality During Short-Term Storage”. The authors should address the following issues to improve the manuscript:

There are many published HWT studies, what is the novel insight of this manuscript? Is it cultivar specificity?

The experiments were conducted in 2014–2015, which makes concerns about the novelty of data unless justified by a compelling reason or new analysis. Please explain the delay in manuscript preparation and submission. Are the findings still relevant to current industry practices or technologies?

Lack of biochemical mechanism testing to support the results of the study. The authors discussed enzymes like PAL, PPO, POD, …, but did not directly measure them.

How were hot water treatment parameters chosen (for examples, 55 °C for 12 s, 45 °C for 10 min,…)? Were these based on preliminary studies or previous publications? If they were from previous studies, please add the citations. A rationale for these specific durations and temperatures should be better clarified.

Did authors conduct microbiological parameters (for example, total plate count or fungal incidence) assessed in this study? Given that rotting was scored visually, the addition of quantitative microbiological data would strengthen the findings.

Was a randomized block design used for tray storage, and how were replicates handled spatially in the chamber?

Positional effects in cold rooms can affect temperature and humidity; So please clarify how these were controlled during experiments.

In the discussion part, please discuss scalability, commercial applicability, and environmental/safety considerations of applying HWT to fresh-cut produce.

In lines 124-132, the authors should use a table to summarize the scales that are used for evaluating fruit quality.

There are many typo errors in the manuscript, for example, lines 100, 275, (18-–20 °C), 165, 175, 180,….

Please add scale bars for Figures 1, 2, 3, 4, and 8.

Unify the terms used in the manuscript, for example “Control-not treated” was used in tables but “Control” was used in figure legends.

Author Response

Thank you very much for taking the time to review this manuscript. Please find the detailed responses below and the corresponding revisions/corrections highlighted/in track changes in the re-submitted files.   Reviewer's comments and authors' responses:

I have reviewed the manuscript titled “The Post-Cutting Hot Water Treatment of Pepper Fruit: Impact on Quality During Short-Term Storage”. The authors should address the following issues to improve the manuscript:

1. There are many published HWT studies, what is the novel insight of this manuscript? Is it cultivar specificity?

Most of the studies refer to HWT of whole vegetables and fruits. Reviewing the literature, I did not come across a report showing differences in the response of different varieties to HWT. Other studies were conducted on red-fruited varieties while in the study presented here, a cream-fruited variety was also tested and showed a different response to HWT than red-fruited pepper.

2. The experiments were conducted in 2014–2015, which makes concerns about the novelty of data unless justified by a compelling reason or new analysis. Please explain the delay in manuscript preparation and submission. Are the findings still relevant to current industry practices or technologies?

The study was conducted a few years ago, and due to other obligations, the writing of the publication was started but not finished. After conducting other studies with cut vegetables (Chinese cabbage, crisp lettuce) and performing a literature review on the subject, we assessed that the results obtained are valuable and can make some contribution to science in this field, or encourage other scientists to further penetrate these issues. Fresh-cut vegetables are a significant branch in fresh vegetable production, so any technology that affects their better shelf life contributes to reducing losses and thus improving economic viability.

3. Lack of biochemical mechanism testing to support the results of the study. The authors discussed enzymes like PAL, PPO, POD, …, but did not directly measure them.

Enzymes were not measured in the presented study, but this is a task for future research as well as other analyses should be performed, such as sensory evaluation of taste and smell.

4. How were hot water treatment parameters chosen (for examples, 55 °C for 12 s, 45 °C for 10 min,…)? Were these based on preliminary studies or previous publications? If they were from previous studies, please add the citations. A rationale for these specific durations and temperatures should be better clarified.

The HW parameters was chosen based on literature report for whole pepper fruit (Fallik et al. 1996, 1999 and 2004; Sgroppo et al. 2009). Preliminary tests were also conducted with the same varieties and promising results were obtained regarding the use of HW. Preliminary results have not been published, the samples in these tests were packed in plastic bags with perforations, but evaluation during storage and shelf life was hampered because the packages became foggy from the inside and accurate evaluation could only be made after the packages were unpacked. The test was repeated in a similar arrangement, but using styrofoam trays for packaging, which did not hinder evaluations during the experiment.

5. Did authors conduct microbiological parameters (for example, total plate count or fungal incidence) assessed in this study? Given that rotting was scored visually, the addition of quantitative microbiological data would strengthen the findings.

Microbiological analyses were performed in preliminary tests and after both one and four days of storage, no Esherichia coli was found in both treated and untreated samples. After one day of storage, in general, the most total bacteria and mold and yeast were in the control samples. After 4 days of storage, an increase in the number of microorganisms was observed, and due to large differences between individual samples within one experimental object, differences between treatments could no longer be determined. In the study presented here, microbiological analyses were no longer performed.

6. Was a randomized block design used for tray storage, and how were replicates handled spatially in the chamber?
7. Positional effects in cold rooms can affect temperature and humidity; So please clarify how these were controlled during experiments.

Answer questions 6 and 7. At each temperature, samples for storage tests were packed into 10 crates.  Four samples from each combination for storage for 6 days were packed into one crate and 2 samples for refrigerated storage for 4 days and further storage at 18-20°C were packed into another crate. The size of the sample packing crates were: 600 x 400 x 135mm (L x W x H). The crates were arranged in two columns, 5 boxes per columns and the height of the column was 65.5 cm ((13.5 + (13 x 4)). This arrangement made it easier to make observations, which had to be done quickly to keep the peppers from heating up. Weighing samples in refrigerated chambers is impossible due to the reaction of the scales to air circulation.  Uniformity of temperature and humidity conditions was ensured by setting the crates in the following way: the crates were placed on 5 cm slats, free spaces (about 10 cm) were left between the wall of the chamber and the crates, and 10 cm free space between the columns of the crates. Such an arrangement of crates provides good air circulation and maintains uniform conditions throughout the chamber. Samples for microscopic observation were packed into separate crate.

8. In the discussion part, please discuss scalability, commercial applicability, and environmental/safety considerations of applying HWT to fresh-cut produce.

HWT is a technology that is safe for the environment and human health and has the potential to improve the storage life of cut vegetables, including fresh-cut peppers. However, it is necessary to strictly follow the recommended rules and especially the water temperature and treatment time. The ability to store fresh-cut peppers under refrigeration for extended periods of time should help significantly reduce losses of both commodities prepared for trade and for use in mass catering facilities: schools, hospitals, military units and others. For products with a longer shelf life, their individual deliveries can be enlarged in favor of reducing their frequency, which also means savings on transportation. On the other hand, it becomes possible to transport it over longer distances, and in this way the market can be expanded. The ability to store longer at 18–20°C is important for retail sales. Goods can maintain good quality longer both on store shelves and in consumers' homes. Information added, L:455 - 466

9. In lines 124 -132 the authors should use a table to summarize the scales that are used for evaluating fruit quality.

The quality assessment scales are given in the table. L: 141

10. There are many typo errors in the manuscript, for example, lines 100, 275, (18-–20 °C), 165, 175, 180,….

The typo errors indicated, have been corrected.

11. Please add scale bars for Figures 1, 2, 3, 4, and 8.

Scale lines to the figures listed, have been added.

12. Unify the terms used in the manuscript, for example “Control-not treated” was used in tables but “Control” was used in figure legends.

“Control – not treated” was used also for figures.

 

 

 

 

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

I do not have additional comments or suggestions.

Author Response

Thank you very much again for taking the time to re-review this manuscript. We apologize for the ambiguity in the previous answer.   Comment 2. Information was added in the manuscript in the lines: 415 - 420 Comment 4. The information is in the manuscript in the lines: 166 – 167 and 223 – 225   Previous Comments and Responses.

1. For example, browning should be quantified using color parameters such as L*, a*, b*, the browning index, and ΔE, determined with a color meter.

 Measurements of L* a* b* color parameters would be very good evidence of differences in the discoloration of the cut surface of peppers, and this is a task to be performed in future tests on cut vegetables. In the presented research, assessments were made based on developed nine-point scales.

2. Similarly, the assessment of softening should be further substantiated by data on the count and types of microorganisms present.

 The microbial load was tested in previous tests (not published) with peppers cut but packed in perforated plastic bags. We were somewhat reassured that there was no Esherichia coli in any of the objects. After one day of storage, in general, the most total bacteria and mold and yeast were in the control samples. After 4 days of storage, an increase in the number of microorganisms was observed, and due to large differences between individual samples within one experimental object, differences between treatments could no longer be determined. In the study presented here, microbiological analyses were no longer performed. Information added L: 415 - 420

 

3. The study assesses various quality parameters such as softening, browning, rotting, and marketable value. However, does heat treatment affect the flavor of the product? This quality indicator should be included, as heat treatment commonly causes changes in flavor in fresh-cut produce, both during and after storage.

 The taste of a food product is very important to achieve consumer acceptability. In the conducted research, the focus was on the appearance of the commodity and in further stages sensory evaluation should be carried out on taste, smell and other distinguishing features.

 

4. Finally, the storage time of different pepper varieties is observed to vary. The manuscript should address the reasons for these differences.

 

The storage time for both varieties was 6 days at cold temperatures (3, 5 and 8°C). Additional samples from both varieties after 1 and 2 days following 4 days at cold storage. In the tables with quality parameters, is lack of the results after 2 days at cold storage, because for the variety Yecla they were only “1” for softening and “9” for commercial value. In lines 166 -167 there is information that after two days there were no signs of deterioration in quality. In the case of ‘Blondy’ only control peppers, after 2 days at 8°C shown very little browning, which is written about in lines 223 -225.

In the tables with weight loss, there were the results after two days, because they have already been found.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

Thank you for providing the revised manuscript. The authors responded positively to almost all the comments. However, they answered the questions without taking action on comments 4 and 5. The authors should add the interpretation of comment 4 in the Materials and Methods section, and that of comment 5 in the Results or Discussion section.

Author Response

Thank you very much again for taking the time to re-review this manuscript.

Information for comment 4 has been added to the text in L: 108 – 111. Information for comment 5 has been added to the text in L: 415 - 420.

Author Response File: Author Response.pdf