Extruded Food Pellets with the Addition of Lucerne Sprouts: Selected Physical and Chemical Properties

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The manuscript presents a well-designed experimental study that examines the effect of lucerne sprout addition and processing parameters on the physical, chemical, and antioxidant properties of extruded pellets. The topic is current and relevant for the readers of Applied Sciences, as it connects food extrusion technology with the development of functional products and the sustainable use of plant materials.
The paper has a clear structure, the experimental design is understandable, and the analytical methods used (WAI, WSI, SME, DPPH, TPC) are appropriate. The obtained results are consistent with the literature and confirm the potential of lucerne sprouts as a functional additive.
However, a few minor revisions are needed before publication, mainly related to the precision of presentation, details of statistical analysis, and language clarity. Therefore, the decision Minor Revisions is suggested.

Comments on shortcomings:

1. The study provides useful data on the extrusion of mixtures with the addition of fresh lucerne sprouts. Originality is moderate: similar studies exist, but the use of fresh sprouts and the comparison of die geometry represent a contribution. In the introduction, it is necessary to emphasize more clearly the novelty and research objective and to explain what specific knowledge gap this paper fills.
2. The description of extrusion parameters is detailed but should be supplemented as follows: indicate the temperature profile across the extruder zones, explain the feed rate and die pressure, and add information on instrument calibration and measurement accuracy. Statistical analysis uses one-way ANOVA, but the design includes several factors (moisture, screw speed, lucerne content, die type). A multifactor ANOVA should be considered or at least a justification given for not using it. Abbreviations such as “SM” should be explained at first appearance.
3. Repetition of numerical values in the text should be avoided (and in the tables), with focus placed on trends and relationships among parameters. It is necessary to add mechanistic explanations (for example, how lucerne fiber affects viscosity, expansion, and texture of extrudates). Figures 1 and 2 (DPPH activity) must be clearly presented with legends and statistical significance indicators. In the section on antioxidant results (DPPH, TPC), a quantitative comparison with literature data is desirable to highlight the effect. The discussion should be linked to practical aspects, such as industrial application potential and contribution to sustainable production of functional snacks.
4. All figures should be properly numbered and, if possible, placed after their first mention in the text. References should be unified according to the MDPI format; one reference. Standard deviations (±SD) and/or error bars should be added to the graphs (Figure 1).
5. The conclusions are accurate but too extensive and partially repeat the results. They should be condensed and focused on practical implications, optimal process conditions, and the significance of lucerne addition for the development of functional foods.

Comments on the Quality of English Language

English is understandable but needs minor language editing by a native or professional editor. Typical issues: word order, redundant expressions (“new assortment of functional food”), and inconsistent tense usage. Improve paragraph transitions and remove some overly literal translations from Polish phrasing.

Author Response

We would like to thank the Reviewer for valuable comments. All corrections needed have been done as requested and marked on red colour.

1. The study provides useful data on the extrusion of mixtures with the addition of fresh lucerne sprouts. Originality is moderate: similar studies exist, but the use of fresh sprouts and the comparison of die geometry represent a contribution. In the introduction, it is necessary to emphasize more clearly the novelty and research objective and to explain what specific knowledge gap this paper fills.

It has been corrected. 

2. The description of extrusion parameters is detailed but should be supplemented as follows: indicate the temperature profile across the extruder zones, explain the feed rate and die pressure, and add information on instrument calibration and measurement accuracy.

It has been corrected. 

3. Statistical analysis uses one-way ANOVA, but the design includes several factors (moisture, screw speed, lucerne content, die type). A multifactor ANOVA should be considered or at least a justification given for not using it. Abbreviations such as “SM” should be explained at first appearance.

The description and statistical analysis were rechecked. The description at section 2.12 was incorrect, and a multi-factor ANOVA was used. The text has been corrected.

4. Repetition of numerical values in the text should be avoided (and in the tables), with focus placed on trends and relationships among parameters. It is necessary to add mechanistic explanations (for example, how lucerne fiber affects viscosity, expansion, and texture of extrudates). Figures 1 and 2 (DPPH activity) must be clearly presented with legends and statistical significance indicators. In the section on antioxidant results (DPPH, TPC), a quantitative comparison with literature data is desirable to highlight the effect. The discussion should be linked to practical aspects, such as industrial application potential and contribution to sustainable production of functional snacks.

Thank you for the valuable comment. The text, including the results and discussion section, was edited based on comments from all reviewers. Information was added, for example, on the effect of the lucerne additive on selected physical properties of the extrudates. Both figures have been improved. Additional information about antioxidant activity of lucerne sprouts have been added. Unfortunately, due to the limited number of studies based on lucerne sprouts, we referred to the most important studies that could be used for comparison with our own results. We wanted to avoid comparing the results of the studies with the properties specified for the plant itself, as we wanted to emphasise the value of the sprouts.

5. All figures should be properly numbered and, if possible, placed after their first mention in the text. References should be unified according to the MDPI format; one reference. Standard deviations (±SD) and/or error bars should be added to the graphs (Figure 1).

Standard deviations have been added to the graphs. The references have been unified.

6. The conclusions are accurate but too extensive and partially repeat the results. They should be condensed and focused on practical implications, optimal process conditions, and the significance of lucerne addition for the development of functional foods.

The entire section has been checked and rebuilt based on all reviewers comments.

7. English is understandable but needs minor language editing by a native or professional editor. Typical issues: word order, redundant expressions (“new assortment of functional food”), and inconsistent tense usage. Improve paragraph transitions and remove some overly literal translations from Polish phrasing.

The English language has been checked by Native Speaker and corrected.

Reviewer 2 Report

Comments and Suggestions for Authors

The manuscript presents an interesting and well-structured experimental study on the use of lucerne sprouts as a functional additive in extruded food pellets. The topic is relevant to the field of food processing and functional food development. The experimental design is systematic, and the results are clearly tabulated. However, several areas require improvement in writing clarity, data interpretation, and scientific depth to meet the publication standards of Applied Sciences after major revision.

1. The abstract is overly detailed; it should emphasize the key findings while shortening the process description
2. Please quantify key outcomes (e.g., % increase in TPC, DPPH values) and avoid repetition of known trends such as “lucerne enrichment increased antioxidant potential”.
3. The introduction provides a good background but is too lengthy and somewhat repetitive. Condense the general information on functional foods (lines 40–70) and emphasize the research gap and clarify the novelty compared with previous studies
4. End the introduction with a clear objective statement e.g., “This study aimed to evaluate how lucerne inclusion and process parameters affect extrusion efficiency, product texture, and antioxidant potential.
5. The material and method section is detailed and several procedural descriptions are unnecessarily long. Condense these while retaining essential parameters.
6. Provide replication details (biological vs. technical replicates). Currently, “each measurement was repeated three times” is stated repeatedly but not linked to sample batches.
7. Clarify whether fresh sprouts were used as-is or pre-dried for compositional uniformity; moisture variation in fresh sprouts may bias extrusion stability
8. Include the extruder temperature profile more precisely (actual zone temperatures), since this is critical for reproducibility
9. Add the particle size distribution of the lucerne paste or the mixed flour after sieving
10. The formula numbering and symbols (e.g., Q = m/t) should be double-checked for consistency with MDPI formatting
11. 10. in formula, write DPPH (%) instead of only %.
12. Please double check the sub-script A₀−A₁ instead of A0−A1 throughout the manuscript
13. In results: Provide statistical comparisons (letters a–i are included but not explicitly discussed in the text). Mention which differences were significant.
14. Please strengthen the discussion by mechanistic reasoning e.g., “Fiber from lucerne likely increased melt viscosity and decreased expansion by limiting starch gelatinization
15. Please improve visual interpretation of figures showing interaction plots (e.g., SME vs. lucerne level at different moisture contents)
16. Figures 1–2 should include statistical error bars and labels showing significant differences (p < 0.05)
17. Provide units and replication (n = 3 ± SD) directly in figure captions
18. Discuss why TPC decreased in one condition (30% LS, 36% SM, 60 RPM = 66 µg GAE/g). Possible degradation or phenolic binding to matrix should be considered.
19. The discussion becomes somewhat review-like in lines 493–535; shorten this by citing key papers and keeping focus on your own findings
20. The conclusions are appropriate but mostly restate results. Please improve it by indicating practical implications, such as: Lucerne inclusion up to 10% yields acceptable physical quality with enhanced antioxidant activity. Higher levels (30%) require process optimization to mitigate densification. Add 1–2 sentences on future work, e.g., “Sensory evaluation and shelf-life studies are recommended to assess consumer acceptance.”
21. The manuscript contains grammatical and redundancies; professional English editing is recommended to enhance readability.

Author Response

We would like to thank the Reviewer for valuable comments. All corrections needed have been done as requested and marked on a red colour.

1. The abstract is overly detailed; it should emphasize the key findings while shortening the process description

It has been corrected.

2. Please quantify key outcomes (e.g., % increase in TPC, DPPH values) and avoid repetition of known trends such as “lucerne enrichment increased antioxidant potential”.

Addiitonal information have been provided in section 3.3

3. The introduction provides a good background but is too lengthy and somewhat repetitive. Condense the general information on functional foods (lines 40–70) and emphasize the research gap and clarify the novelty compared with previous studies

It has been corrected.

4. End the introduction with a clear objective statement e.g., “This study aimed to evaluate how lucerne inclusion and process parameters affect extrusion efficiency, product texture, and antioxidant potential.

It has been added.

5. The material and method section is detailed and several procedural descriptions are unnecessarily long. Condense these while retaining essential parameters.

This section has been reviewed and revised based on feedback from all reviewers. Some information has been shortened.

6. Provide replication details (biological vs. technical replicates). Currently, “each measurement was repeated three times” is stated repeatedly but not linked to sample batches.

It has been corrected and added at the end of methodology section.

7. Clarify whether fresh sprouts were used as-is or pre-dried for compositional uniformity; moisture variation in fresh sprouts may bias extrusion stability

Information has been added. Fresh lucerne sprouts were used. Before ground and added to final mixture sprouts were packed in hermetically sealed packages under a controlled atmosphere.

8. Include the extruder temperature profile more precisely (actual zone temperatures), since this is critical for reproducibility

It has been added.

9. Add the particle size distribution of the lucerne paste or the mixed flour after sieving

This information was included in the first version of the manuscript in section 2.2

10. The formula numbering and symbols (e.g., Q = m/t) should be double-checked for consistency with MDPI formatting.

All formulas have been checked and changed according suggestion and MDPI formatting style.

11. in formula, write DPPH (%) instead of only %.

It has been corrected.

12. Please double check the sub-script A0−A1 instead of A0−A1 throughout the manuscript

It has been corrected.

13. In results: Provide statistical comparisons (letters a–i are included but not explicitly discussed in the text). Mention which differences were significant.

It has been corrected and added in the Results section.

14. Please strengthen the discussion by mechanistic reasoning e.g., “Fiber from lucerne likely increased melt viscosity and decreased expansion by limiting starch gelatinization”

The text, including the results and discussion section, was edited based on comments from all reviewers. Information was added, for example, on the effect of the lucerne additive on selected physical properties of the extrudates.

15. Please improve visual interpretation of figures showing interaction plots (e.g., SME vs. lucerne level at different moisture contents)

Thank you for your valuable comment regarding the visual interpretation of the results. In the analysis of the interactions (e.g., SME level depending on the alfalfa level and moisture content), the results were presented in tabular form, accompanied by a complete statistical analysis and a detailed discussion in the text. We chose this format as it allows for precise presentation of numerical values and interaction effects, which might be less clear in a graphical form. It is worth noting that the other reviewers did not suggest any changes to the above method of visualizing the results.

16. Figures 1–2 should include statistical error bars and labels showing significant differences (p < 0.05).

Errors bars have been added to the charts. Significant differences have been provided in the form of descriptions below the relevant graphs. We wanted to avoid reducing the clarity of the graphs.

17. Provide units and replication (n = 3 ± SD) directly in figure captions

It has been corrected.

18. Discuss why TPC decreased in one condition (30% LS, 36% SM, 60 RPM = 66 µg GAE/g). Possible degradation or phenolic binding to matrix should be considered.

The additional analysis has been provided.

19. The discussion becomes somewhat review-like in lines 493–535; shorten this by citing key papers and keeping focus on your own findings.

Thank you for valuable comment. We removed unnecessary information, but the Reviewer 1. suggested adding research results found in the literature (focusing on specific activity values and active compound contents), which is why this section has been expanded with additional data.

20. The conclusions are appropriate but mostly restate results. Please improve it by indicating practical implications, such as: Lucerne inclusion up to 10% yields acceptable physical quality with enhanced antioxidant activity. Higher levels (30%) require process optimization to mitigate densification. Add 1–2 sentences on future work, e.g., “Sensory evaluation and shelf-life studies are recommended to assess consumer acceptance.”

The entire section has been checked and rebuilt based on all reviewers comments.

21. The manuscript contains grammatical and redundancies; professional English editing is recommended to enhance readability

The English language has been checked by Native Speaker and corrected.

Reviewer 3 Report

Comments and Suggestions for Authors

1. The duplication rate of the manuscript is too high, exceeding 15% for a single article.
2. Authors state using one-way ANOVA (Section 2.12), but the experimental design clearly contains multiple factors (lucerne%  × screw speed × moisture × die geometry). A multi-factor ANOVA is required to properly evaluate main effects and interactions.
3. Authors state lucerne causes denser pellets (Conclusion lines 549–550), but in the flat-die results at 100 rpm/36% moisture, 30% lucerne produces lower bulk density vs. 0% (Table 2).
4. Table 1 shows that some high-moisture conditions increase SME (e.g., 10% lucerne with a flat die at 60 rpm). It is the opposite of typical extrusion effects.
5. Missing Methodological Details. Please include: 1. Feed mass flow rate (constant? how controlled?) 2. Replicate number for each process run in Table 1. 3. Exact storage duration before antioxidant assays.

Author Response

We would like to thank the Reviewer for valuable comments. All corrections needed have been done as requested and marked on red colour.

1. The duplication rate of the manuscript is too high, exceeding 15% for a single article.

The manuscript has been changed. It’s duplication rate should be lower.

2. 
   Authors state using one-way ANOVA (Section 2.12), but the experimental design clearly contains multiple factors (lucerne% × screw speed × moisture × die geometry). A multi-factor ANOVA is required to properly evaluate main effects and interactions.

The description and statistical analysis were rechecked. The description at section 2.12 was incorrect, and a multi-factor ANOVA was used. The text has been corrected.

3. 
   Authors state lucerne causes denser pellets (Conclusion lines 549–550), but in the flat-die results at 100 rpm/36% moisture, 30% lucerne produces lower bulk density vs. 0% (Table 2).

The entire section has been checked and rebuilt based on all reviewers comments.

4. Table 1 shows that some high-moisture conditions increase SME (e.g., 10% lucerne with a flat die at 60 rpm). It is the opposite of typical extrusion effects.

Thank you for your valuable comment. The study found that, specifically for the case of 0% lucerne sprouts addition with a flat die and processing at 60 rpm, higher SME values ​​can be obtained when processing blends have higher moisture content. These observations are also consistent with the conclusions from other studies (e.g., da Silva et al. 2014. Physical characteristics of extrudates from corn flour and dehulled carioca bean flour blend. LWT-Food Science and Technology, 58, 620–626. DOI: 10.1016/j.lwt.2014.03.031; Meng et al. 2010. Effects of extrusion conditions on system parameters and physical properties of a chickpea flour-based snack. Food Research International, 43, 650–658. DOI: 10.1016/j.foodres.2009.07.016). Mentioned authors stated that, among other conditions, the moisture content of the mixture may not have a significant effect on the SME values ​​obtained during the extrusion cooking process.

5. 
   Missing Methodological Details. Please include: 1. Feed mass flow rate (constant? how controlled?) 2. Replicate number for each process run in Table 1. 3. Exact storage duration before antioxidant assays.

Information added.

 

 

 

 

 

 

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

accept

Reviewer 3 Report

Comments and Suggestions for Authors

It is OK.