Chemical Profiling and Sensory Analysis Reveal Quality Differentiation in Baimudan White Tea Processed from Three Major Fujian Tea Cultivars

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

You must change the temperature units, separating them from the number.
You must explain the statistics used in more detail.

Comments for author File: Comments.pdf

Author Response

We appreciate the reviewer’s careful reading of our manuscript and the constructive comments. Our point-by-point responses are as follows:

Comment 1: "You must change the temperature units, separating them from the number."

Response1: Thank you for pointing this out. We have carefully checked the entire manuscript and have revised all temperature expressions to include a space between the numerical value and the unit (e.g., "25 °C" instead of "25°C"). We apologize for the oversight in the original submission.

Comment 2: "You must explain the statistics used in more detail."

Response2: We appreciate this important suggestion. In the revised manuscript (Materials and Methods section), we have added a detailed explanation of the statistical methods employed, including the rationale for selecting them, the specific tests used, and the criteria for significance. Furthermore, following your earlier recommendation, we have also separated the explanations for equations (1) and (2) (TAV and OAV) to ensure clarity.

Reviewer 2 Report

Comments and Suggestions for Authors

L45-46 What are the global and national production levels of this food? What health benefits does this tea provide?
L75 What sensory attributes have been detected in this food? A more in-depth review is recommended.
Add the problem, research question, and hypothesis to be tested in the introduction. Also, clarify the objective of the work.
As the title indicates, sensory analysis is necessary to include a paragraph detailing the sensory properties and the techniques used for their identification.
In section 2.2, many methodological points need to be clarified. They used the QDA technique but do not mention the panel size (how many women and men, age range, experience in sensory evaluation, what international standards were used), how many evaluation sessions were conducted, and how many repeat sessions? What were the experimental conditions of the samples (temperature, quantity, aerosolization, experimental design used for distributing the samples to each panelist), statistical techniques for validating the panel's performance? How was the sensory vocabulary defined (focus group, ISO 110135:1994 standard, multicriteria techniques?)? I recommend reading and citing the following article (https://doi.org/10.3168/jds.2017-14213).
The beginning of section 31 should include the results of the panel's performance as a measure of validation and reliability of the results.
Include the sensory component in the discussion and provide further explanation of these results.
What were the limitations of the research?

Author Response

We appreciate the reviewer’s careful reading of our manuscript and the constructive comments. Our point-by-point responses are as follows:

Comments 1: L45-46 What are the global and national production levels of this food? What health benefits does this tea provide?

Response 1: Our initial statement was general. We have revised the manuscript to include specific details about white tea production.  Globally, white tea production is primarily concentrated in China, with Fujian province being the leading region, notably Fuding and Zhenghe.  While it represents a niche segment compared to green or black tea, China's white tea output has experienced significant growth, reaching approximately 93,800 tons, accounting for 2.6% of the total tea yield in 2024.Furthermore, white tea possesses various health benefits owing to its rich bioactive compounds such as polyphenols, flavonoids, and polysaccharides, which contribute to its strong antioxidant, anti-inflammatory, neuroprotective, anti-diabetic, anti-obesity, and potential anticancer effects.

We have integrated these expanded details regarding white tea's production and health benefits into the introductory section (L45-52) of the manuscript, aiming to provide readers with a more comprehensive understanding of its industrial landscape and associated health properties.

Comments 2: L75 What sensory attributes have been detected in this food?

Response 2: Thank you for your insightful question regarding the sensory attributes detected in this food. We understand that you are specifically interested in the distinctive quality characteristics of white tea produced from high-aroma Oolong cultivars when compared to white tea made from conventional varieties. Drawing from previous research, it has been observed that white tea processed from high-aroma Oolong cultivars typically exhibits a more pronounced and complex aromatic profile. Specifically, these teas tend to possess richer floral, sweet floral, and honey-like notes, or unique varietal aromas, which are generally less intense in white teas made from traditional cultivars. Regarding taste, however, these high-aroma white teas may present a slightly astringent sensation, in contrast to the often smoother mouthfeel of conventional white teas.

We have clarified and expanded on these specific comparative sensory attributes in the revised manuscript, particularly at L80-81, to provide readers with a comprehensive understanding of the distinct quality characteristics of these innovative white tea products.

Comments 3: A more in-depth review is recommended. Add the problem, research question, and hypothesis to be tested in the introduction. Also, clarify the objective of the work.

Response 3: We appreciate the reviewer’s suggestion. In the revised Introduction, we have expanded the literature review to provide a more in-depth synthesis of current research progress, highlighting both achievements and knowledge gaps in the study of white tea cultivar-dependent flavor characteristics. Specifically, we now (i) identify the existing problem — the lack of systematic comparative analysis of sensory attributes and key metabolites among Baimudan white teas made from Fujian’s three dominant cultivars; (ii) explicitly state our research question — how differences in volatile compounds, amino acids, and sugars among these cultivars contribute to their distinctive sensory profiles; and (iii) present our working hypothesis — that each cultivar possesses a unique metabolite composition that drives characteristic sensory attributes, particularly in floral aroma, freshness, and umami intensity. Furthermore, we have clarified the specific objective of this work — to integrate targeted metabolomics and quantitative descriptive analysis to establish the biochemical basis for flavor differentiation, thereby providing a theoretical reference for cultivar selection and quality optimization in white tea production. These revisions are reflected in the last paragraph of the Introduction (Lines 92–103).

Comments 4: As the title indicates, sensory analysis is necessary to include a paragraph detailing the sensory properties and the techniques used for their identification.

Response 4: In the revised manuscript, we have added a paragraph in the Materials and Methods section to describe the sensory evaluation procedure, including the panel composition, evaluation environment, and reference standards. We have also provided a detailed characterization of the five aroma attributes—fresh, floral, fruity, sweet, and tip—as perceived in Baimudan white tea. Specifically, “fresh” was described as having a light grassy scent with a faint cucumber-like freshness; “floral” referred to a subtle orchid fragrance; “fruity” corresponded to a green-apple-like aroma; “sweet” was characterized by honey-like and sweet-fat notes; and “tip” denoted the distinctive, delicate aroma of tea buds. The identification of these attributes was based on consensus among trained panelists, using a quantitative descriptive analysis approach (QDA) with reference standards to calibrate perceptions. These additions can be found in Section 2.2 of the revised manuscript.

 

Comments 5: In section 2.2, many methodological points need to be clarified. They used the QDA technique but do not mention the panel size (how many women and men, age range, experience in sensory evaluation, what international standards were used), how many evaluation sessions were conducted, and how many repeat sessions? What were the experimental conditions of the samples (temperature, quantity, aerosolization, experimental design used for distributing the samples to each panelist), statistical techniques for validating the panel's performance? How was the sensory vocabulary defined (focus group, ISO 110135:1994 standard, multicriteria techniques?)? I recommend reading and citing the following article (https://doi.org/10.3168/jds.2017-14213).

Response 5: We thank the reviewer for the constructive comments. We have now substantially expanded Section 2.2 to provide a detailed description of the QDA methodology. Specifically, we have added:（1）Panel composition (number of panelists, gender ratio, age range, sensory evaluation experience, selection criteria).（2）International and national standards followed for panel selection and evaluation (GB/T 16291.1-2012, GB/T 23776-2018）（3）Number of evaluation sessions and repetitions per sample（4）Experimental conditions for sample preparation and presentation (temperature, infusion volume, brewing time).

We have also cited the recommended reference (JDS 2017, https://doi.org/10.3168/jds.2017-14213) in this section.

These modifications can be found in the revised manuscript (Section 2.2, Lines 145–173).

Comments 6: The beginning of section 31 should include the results of the panel's performance as a measure of validation and reliability of the results.

Response 6:We appreciate the reviewer’s suggestion to include the panel performance results at the beginning of Section 3.1. In the present study, we did not repeat the PanelCheck software analysis. However, the same trained sensory panel was used in our previous study (Zheng et al. 2025), where their performance (discrimination ability, repeatability, and consensus) was validated using PanelCheck software. The results of that study confirmed that the panel met the acceptable criteria for sensory evaluation of tea. In the current work, we further ensured reliability by using the same trained panelists, evaluating each sample in duplicate across independent sessions, and finding no significant differences between repeated evaluations. In the revised manuscript, we have added this information at the beginning of Section 3.1 to demonstrate the robustness and reliability of the sensory data.

Comments 7: Include the sensory component in the discussion and provide further explanation of these results.

Response 7: We thank the reviewer for the valuable suggestion to incorporate the sensory evaluation component into the Discussion and to provide further interpretation of these results. In the revised manuscript, we have added explicit discussion linking the sensory profiles of the three cultivars with their corresponding chemical compositions. Specifically, we now explain how the higher levels of umami-related amino acids (theanine, glutamic acid, aspartic acid) in ZHDB and FADB correspond to their higher umami scores, and how elevated concentrations of floral volatiles (methyl salicylate, linalool, β-ionone) in these cultivars underpin their stronger fresh–floral aroma. Similarly, we relate the higher sucrose content  in FDDH to its stronger sweetness scores. These additions are highlighted in the Discussion section ( lines 523–532 in the revised manuscript) to provide a more integrated interpretation of sensory and metabolomic data.

Comments 8: What were the limitations of the research?

Response 8: We thank the reviewer for pointing out the importance of discussing the limitations of our study. In the revised manuscript, we have added a statement at the end of the Conclusion section to explicitly acknowledge the main limitations. Specifically, we note that (1) the number of tea samples analyzed was relatively small, which may limit the generalizability of the findings to broader production areas and harvest years, and (2) although we identified key metabolites potentially responsible for sweetness, umami, and floral aroma, their causal roles in sensory perception were not validated by aroma recombination experiments. We also indicate that future work will expand the sampling scope and employ such confirmatory sensory experiments to further substantiate the links between specific compounds and flavor attributes in white tea. These additions have been incorporated into the Conclusion section.

Reviewer 3 Report

Comments and Suggestions for Authors

The article provides a detailed chemical and sensory analysis of Baimudan white tea produced from three main tea cultivars from Fujian Province, China. The main objective was to understand why these white teas, even though they are of the same type (Baimudan), differ in flavor and aroma, despite being processed under the same conditions. To this end, the study evaluated the chemical composition (amino acids, sugars, and volatile compounds) and sensory profile of each cultivar.

 

- In food chemistry, it's important to mention whether the replicates are biological, technical, or both. It's mentioned that they were performed in triplicate, but I think it's important to clarify this in the article.

- The authors are encouraged to elaborate on sensory evaluations such as training, panel validation, and the scale used.

- Authors are encouraged to justify the statistical approach they used, i.e., explain why certain multivariate techniques were chosen in each of the analyses.

- The results section presents too many extensive tables. Some (such as the one on 380 volatiles) could perhaps be modified as supplementary material.

- The results show a lack of clear correlations between chemical compounds and sensory attributes, except for the qualitative comments. The authors are encouraged to perform a statistical correlation analysis (e.g., PLSR).

- Authors are encouraged to improve the resolution of the PCA figure.

- The discussion is limited, and the practical impact on the tea industry is not observed. How can these results guide cultivar selection or marketing strategies?

- The discussion notes little comparison with reports in the existing literature. Only general studies are cited; specific comparisons with other research on white tea or with the same cultivars are lacking. Improved discussions of the results are recommended.

Comments on the Quality of English Language

The manuscript demonstrates acceptable scientific English, but contains frequent grammatical errors. The authors are encouraged to review the entire manuscript and correct any errors.

Author Response

We appreciate the reviewer’s careful reading of our manuscript and the constructive comments. Our point-by-point responses are as follows:

Comments 1:In food chemistry, it's important to mention whether the replicates are biological, technical, or both. It's mentioned that they were performed in triplicate, but I think it's important to clarify this in the article.

Response 1: We thank the reviewer for highlighting the importance of clarifying the type of replicates used. In all experiments of this study, three independent biological replicates were performed. The revised text can be found in Section 2.1.

Comments 2:The authors are encouraged to elaborate on sensory evaluations such as training, panel validation, and the scale used.

Response 2: We thank the reviewer for the constructive comments. We have now substantially expanded Section 2.2 to provide a detailed description of the QDA methodology. Specifically, we have added:（1）Panel composition (number of panelists, gender ratio, age range, sensory evaluation experience, selection criteria).（2）International and national standards followed for panel selection and evaluation （3）Number of evaluation sessions and repetitions per sample（4）Experimental conditions for sample preparation and presentation (temperature, infusion volume, brewing time, serving order, randomization).These modifications can be found in the revised manuscript (Section 2.2).

Comments 3:Authors are encouraged to justify the statistical approach they used, i.e., explain why certain multivariate techniques were chosen in each of the analyses.

Response 3:We thank the reviewer for the insightful comment regarding the justification of our statistical approach. In this study, we compared the concentrations of aroma compounds, amino acids, and carbohydrates among three tea cultivars. Since each compound was measured across more than two groups (three cultivars) with three independent biological replicates, we first conducted a one-way analysis of variance (ANOVA) to determine whether there were significant differences among the cultivars. When the ANOVA indicated significance (p < 0.05), Duncan’s multiple range test (DMRT) was applied as a post-hoc comparison to identify which specific cultivar pairs differed.

Duncan’s test was chosen because it is widely used in food chemistry and agricultural product quality evaluation, offering a balance between statistical power and control of type I error in multiple comparisons. Moreover, it allows results to be presented in an intuitive grouping format (e.g., a, b, c), which is clear and informative for readers interpreting compositional differences. This clarification has been added to the Materials and Methods section 2.7 of the revised manuscript.

Comments 4:The results section presents too many extensive tables. Some (such as the one on 380 volatiles) could perhaps be modified as supplementary material.

Response 4:We sincerely appreciate the reviewer’s suggestion regarding the extensive tables presented in the Results section. We understand the concern about the length of the results and the potential benefit of moving certain large datasets to the supplementary material.

However, we would like to note that the volatile compounds table is considered an essential part of this study. It directly presents the screening outcomes for the key aroma-active compounds, which are central to the interpretation of our findings and the conclusions drawn. In research related to tea quality, such a comprehensive volatile profile table is commonly included in the main text to allow readers immediate access to critical data without needing to consult supplementary files. We believe that keeping this table in the main text will help maintain clarity and completeness for readers, and will support transparency and reproducibility of the results.

If the reviewer was instead referring to the “full volatile profile” table containing all 380 compounds, this dataset has already been provided as Supplementary File 2. We apologize for not marking this clearly in the Results section in the previous version — it was only mentioned in the Materials and Methods section. We have now revised the Results section to clearly indicate that the complete volatile dataset is available in Supplementary File 2, while the main text presents only the key aroma-active compounds.

If the reviewer and editor consider it necessary for manuscript length or readability, we are willing to move this table to the supplementary material while ensuring that the main text still contains a condensed summary of the core results.

Comments 5:The results show a lack of clear correlations between chemical compounds and sensory attributes, except for the qualitative comments. The authors are encouraged to perform a statistical correlation analysis (e.g., PLSR).

Response 5: Thank you for your insightful feedback and valuable suggestion regarding the statistical correlation analysis, particularly the use of Partial Least Squares Regression (PLSR). We fully agree that establishing quantitative links between chemical compounds and sensory attributes is a crucial aspect of this research.

However, we have decided not to employ PLSR for this analysis. The primary reason for this decision is the extremely limited sample size in our study (N=3). PLSR, while a powerful multivariate technique for handling multicollinearity and multiple responses, relies on a sufficient number of samples for robust model building, reliable inference, and stable cross-validation. With N=3, the maximum number of latent components that can be extracted is severely restricted (N-1 = 2 components). Furthermore, performing cross-validation for model selection and performance evaluation (e.g., RMSEP) becomes highly unstable and unreliable with such a small dataset. This limitation significantly increases the risk of overfitting, compromises the generalizability and statistical power of any PLSR model, and makes any derived statistical significances or predictive outcomes highly questionable and potentially misleading. Therefore, we believe that forcing a PLSR analysis under these conditions would not yield stable or meaningful statistical insights.

To address your valuable suggestion in a statistically appropriate manner given our small sample size, we have calculated pairwise correlations between chemical compounds and sensory attributes using Spearman's rank correlation coefficients. This non-parametric approach is well-suited to small datasets and does not require the strict assumptions inherent in PLSR. The detailed correlation matrices for amino acids, carbohydrates, and key aroma compounds with their corresponding sensory attributes have been provided in the Supplementary Materials (Tables S3–S4). In addition, we have incorporated the most relevant and statistically significant correlation results into the revised Results section to strengthen the quantitative linkage between chemical composition and sensory perception in Baimudan white tea.

Comments 6:Authors are encouraged to improve the resolution of the PCA figure.

Response 6:We thank the reviewer for the valuable suggestion. In the revised manuscript, the PCA figure has been replaced with a higher-resolution version. The Fig.4 (5290 × 3000 pixels, 762 DPI) meets and exceeds the journal’s image quality requirements. We believe the improved figure will enhance the clarity and readability of the results.

Comments 7:The discussion is limited, and the practical impact on the tea industry is not observed. How can these results guide cultivar selection or marketing strategies?

Response 7:We thank the reviewer for pointing out the need to strengthen the discussion regarding the practical implications of our findings for the tea industry. In the revised Discussion section ( L 529–535), we have added a new paragraph that links our chemical and sensory analysis results to cultivar selection and marketing strategies.

Comments 8:The discussion notes little comparison with reports in the existing literature. Only general studies are cited; specific comparisons with other research on white tea or with the same cultivars are lacking. Improved discussions of the results are recommended.

Response 8:Thank you for the reviewers' suggestions,we have thoroughly revised and expanded the discussion paragraphs pertaining to the formation of white tea aroma quality. We have now incorporated specific comparisons with other white tea studies. In particular, the contributions of some key aroma substances in other white tea research were focused on, and the similarities and differences with our research results were discussed.

Comments 9:The English could be improved to more clearly express the research.

Response 9: We sincerely appreciate your suggestion regarding the language quality of our manuscript. The manuscript has been professionally edited by a certified language editing service, and we have the corresponding certificate available upon request. In addition, in response to your comment, we have carefully re-read the revised manuscript and made further minor adjustments to wording and sentence structure where necessary, to ensure clarity, accuracy, and readability. We believe the current version is now polished and meets the standard for publication.

 

Reviewer 4 Report

Comments and Suggestions for Authors

The manuscript presents the chemical and sensory characterization of three varieties of white tea. The methodology used is noteworthy and provides an in-depth understanding of the composition. The manuscript's structure is appropriate and well-systematized. The results obtained allow for the accumulation of scientific data on this product.

However, there are some aspects that should be taken into account to present the manuscript adequately.

The details are as follows:

1. Indicate the scientific name.
2. L32-33. Does it refer to two or three?
3. Indicate the boiling point.
4. In 2.7. Indicate the statistical techniques used.
5. The term "bright" could be better explained.
6. The authors could include an integrative paragraph of the results, since these are isolated, meaning the results should be connected and interacted.
7. The authors could conclude by considering each variety of tea and indicate the most notable values. They could also indicate the challenges to be overcome.

Author Response

We appreciate the reviewer’s careful reading of our manuscript and the constructive comments. Our point-by-point responses are as follows:

Comments 1: Indicate the scientific name.

Response 1: Thank you for your valuable suggestion. Due to the word limit constraints of the abstract, we have provided the full scientific name of the tea plant, Camellia sinensis cv.‘Zhenghedabaicha’ (ZHDB), Camellia sinensis cv.Fuandabaicha (FADB), and Camellia sinensis cv.Fudingdahaocha (FDDH), in the Materials and Methods section.

Comments 2: L32-33. Does it refer to two or three?

Response 2: Thank you for pointing out the ambiguity. We intended to convey that sweetness differences were primarily due to two main categories of compounds: sucrose and sweet-tasting amino acids. Serine and asparagine were highlighted as notable examples within the sweet-tasting amino acid group. We have revised the sentence for clarity as follows: Sweetness differences were largely due to sucrose, serine, and asparagine.

Comments 3: Indicate the boiling point.

Response 3:  we have now supplemented the boiling points for the key substances mentioned. This information is now provided in Supplementary Table 5.

Comments 4: In 2.7. Indicate the statistical techniques used.

Response 4: We sincerely apologize for this oversight. Thank you for pointing out the omission. We have now  revised Section 2.7 (Statistical Analysis) to include a detailed description of all statistical techniques employed in this study.

Comments 5:  The term "bright" could be better explained.

Response 5: Thank you for seeking clarification on the term 'bright' in our description of liquor color. We understand that this term might be perceived as subjective in a general context. In the field of tea sensory evaluation, however, 'bright' (or 'brilliant') is a widely recognized and standardized descriptor for liquor clarity and luster, indicating that the infusion is transparent, clear, and vibrant, rather than dull, cloudy, or turbid. It implies a high degree of transparency and a lively appearance, which is a key quality indicator for tea infusions. To ensure better understanding for a broader scientific audience, we have revised the description in the manuscript to clarify this term. We have changed 'bright apricot-yellow infusions' to 'bright (clear and vibrant) apricot-yellow infusions'.

Comments 6:  The authors could include an integrative paragraph of the results, since these are isolated, meaning the results should be connected and interacted.

Response 6:Thank you for this insightful comment. We agree that a more integrative discussion of the results is crucial for enhancing the clarity and impact of our findings. Our initial presentation might have appeared somewhat isolated.

To address this, we have revised the Discussion section and expanded existing paragraphs to provide a more comprehensive and integrative discussion（L523-539）. We have focused on connecting the sensory evaluation results with the biochemical component analyses, explaining how specific biochemical compounds may influence the observed sensory attributes (e.g., aroma, taste). This integration aims to highlight the interactions between different aspects of our results and offer a more holistic understanding of the tea quality characteristics.

Comments 7: The authors could conclude by considering each variety of tea and indicate the most notable values. They could also indicate the challenges to be overcome.

Response 7:Thank you for this insightful comment. In the discussion section, we have explicitly summarized the significant implications of our findings for the tea industry and their potential reference value for the classification of white tea product grades, directly addressing the practical relevance of our results. we fully agree on the importance of acknowledging limitations and future directions. We have added a dedicated paragraph in the Conclusion section that clearly outlines the limitations of the current study and the challenges to be overcome in future research.

Round 2

Reviewer 3 Report

Comments and Suggestions for Authors

No commets

Reviewer 4 Report

Comments and Suggestions for Authors

The authors have taken the suggestions into account in each case. I have no further questions. Congratulations to the researchers.