Aroma Compounds Are Responsible for an Herbaceous Off-Flavor in the Sweet Cherry (Prunus avium L.) cv. Regina during Fruit Development

Round 1

Reviewer 1 Report

The manuscript includes very interesting original data that can be of great practical importance. However, several issues should be corrected and explained:

lines 71-73: It has been written: "accumulation of volatile compounds in sweet cherry Regina during fruit ripening correlates with the development of herbaceous off-flavors, and that there is an environmental effect due to microclimate and growing conditions". However, the Authors did not provide detailed information about the microclimate and growing conditions for each orchard separately.

2.2. Sensory analysis
The description is not understandable. 
Are sweet cherries from one orchard tasted by panelists at one sitting? What about fruit from other orchards? Are the samples from all orchards were tasted one day at once?

2.3. Volatile extraction

Was one repetition for each half of sweet cherry examined?
How was the sample of twenty grams of fresh sweet cherry flesh and peel prepared? Was this sample randomly extracted from half of the sweet cherry?

2.6. Statistical analysis

Have the assumptions for ANOVA been checked? What tests were used?

Some of the analyzes included in the Supplementary material are not described in section 2. Materials and Methods. 

3. Results
The results of the sensory analysis are not explained and discussed sufficiently. 

line 412: It has been written: "the off-flavor could be the results of soil, microclimate, sun exposure, as well as preharvest practices altering the rate of ripening, and less strongly influenced by the geographical location". Why did the authors not consider these all factors in detail? 

Was an herbaceous flavor reported only for sweet cherry "Regina"? I think that would be very valuable to perform a similar experiment for other cultivars. 

 

 

Author Response

RESPONSE TO THE REVIEWER

REVIEWER 1

The manuscript includes very interesting original data that can be of great practical importance. However, several issues should be corrected and explained:

lines 71-73: It has been written: "accumulation of volatile compounds in sweet cherry Regina during fruit ripening correlates with the development of herbaceous off-flavors, and that there is an environmental effect due to microclimate and growing conditions". However, the Authors did not provide detailed information about the microclimate and growing conditions for each orchard separately.

Answer: We re-wrote the lines 71-73 in order to correctly express what we studied and what is presented in the paper. The last sentence of the hypothesis ‘and that there is an environmental effect due to microclimate and growing conditions’ was changed to ‘and that there is an environmental effect due to climate and geographical zone’(L72-75).

2.2. Sensory analysis.

The description is not understandable. Are sweet cherries from one orchard tasted by panelists at one sitting? What about fruit from other orchards? Are the samples from all orchards were tasted one day at once?

Answer: We thank the reviewer for this comment, the requested information was added to the sensory analysis sub-section in L117-122. We hope it is now more clear.

2.3. Volatile extraction

Was one repetition for each half of sweet cherry examined? How was the sample of twenty grams of fresh sweet cherry flesh and peel prepared? Was this sample randomly extracted from half of the sweet cherry?

Answer: The Volatile extraction sub-section was modified to include the preparation procedure of the twenty grams composite sample L127-130.

2.6. Statistical analysis

Have the assumptions for ANOVA been checked? What tests were used?

Answer: We are aware of the possible inconveniences when applying parametric analyses to percentage data, we re-run the ANOVA using the angular transformation (arcsin) and tested normality by the Shapiro-Wilk and Kolmogorov-Smirnov tests, also Q-Q plot and homoscedasticity plot were carried out. The ‘angular transformation’ is now specified in L162-163.

Some of the analyzes included in the Supplementary material are not described in section 2. Materials and Methods. 

Answer: The Materials and Methods section were modified to mention the methodology of the Supplementary material results where is appropriate in the text for each Table/Figure.

3. Results

The results of the sensory analysis are not explained and discussed sufficiently. 

Answer: We are aware of the need of more formal sensory analysis related to the study and further characterization of the off-flavor occurrence, however, in this work the goal of the sensory analysis was only for classification purposes. For this reason, we modified the “Sensory analysis” subtitle in the Materials and Methods and changed it to “Fruit classification by sensory evaluation” (L107).

Likewise, we modified the “Sensory analysis” subtitle under Results to “Off flavor occurrence by sensory evaluation”.

line 412: It has been written: "the off-flavor could be the results of soil, microclimate, sun exposure, as well as preharvest practices altering the rate of ripening, and less strongly influenced by the geographical location". Why did the authors not consider these all factors in detail? 

Answer: There are many possible causes which can produce variation in the volatile profile and the final perception of flavor that were not fully studied. During previous seasons we did study the sun exposure and shade effects on the development of the herbaceous flavor, but these findings alone did not show light on the ontogeny of the off-flavor. Later, we realized that possibly it was a ‘volatile’ being implicated, therefore, we decided to take the sensory, volatile, and geographical approach. The sentence in line 412 (L426-428 in the new document) was written only to mention some of the variables that may be involved in the different volatile profiles between two production zones which are near from each other such as the case of orchards 2 and 3.

Was an herbaceous flavor reported only for sweet cherry "Regina"? I think that would be very valuable to perform a similar experiment for other cultivars.

Answer: This is the first mention of the off-flavor reported in a formal study. During our initial investigation, other sweet cherry varieties (such as Bing, Sentenial and Skeena) were tested, but the off-flavor was only perceived in Regina, in agreement with the producers and receivers complaints. However, we do not rule out the possibility that other varieties in other countries may present the same problem.

 

 

Reviewer 2 Report

The manuscript entitled "Aroma compounds are responsible for an herbaceous off flavor in the sweet cherry (Prunus avium L.) cv. Regina during fruit development" is well-written and conducted. I have few comments to improve its quality:

 

Introduction

L67-70: in my opinion this part does not belong to the Introduction section: "In this work we ... of sweet cherry in Chile." The aim should be stated, it is a conclusion of study.

 

Results

Table 2. can be removed, no makes sense mentioning such a table in a research article

 

Reference

they are not styled in accordance with the journal's guideline

Author Response

REVIEWER 2

Comments and Suggestions for Authors

The manuscript entitled "Aroma compounds are responsible for an herbaceous off flavor in the sweet cherry (Prunus avium L.) cv. Regina during fruit development" is well-written and conducted. I have few comments to improve its quality:

 

Introduction

L67-70: in my opinion this part does not belong to the Introduction section: "In this work we ... of sweet cherry in Chile." The aim should be stated, it is a conclusion of study.

Answer: We re-phrase the mentioned Lines in order to better reflect the intention of the research (Lines 67-72).

Results

Table 2. can be removed, no makes sense mentioning such a table in a research article

Answer: We believe Table 2 is important to the correct interpretation of the PCA (Figure 6B) and the discussion. Also, we believe it is a good tool for the reader to have a comprehensive understanding of the results. However, if the reviewer feels strongly it should be removed, we would agree to place this table in the supplemental materials.

Reference

they are not styled in accordance with the journal's guideline

Answer: The references are now showed with the appropriate style.

 

Round 2

Reviewer 1 Report

The manuscript has been significantly improved. I recommend accepting the manuscript in its present form.