Experimental Study of Combined Fluidized Bed and Microwave Drying Applied to Soybeans and Pumpkin Seeds^†

Response to Reviewer Comments

1. Summary

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

3. Point-by-point response to Comments and Suggestions for Authors

Comment 1: Keywords on line 20, you should add experimental materials (soybeans, pumpkin seeds).

Answer: Soybeans and pumpkin seeds were included in the keywords

Comment 2: Line 23 mentions hot air drying, but hot air drying is not related to this paper, so I hope to delete it.

Answer: The opening sentence has been revised. Nevertheless, the reference to hot-air drying as the most widely used technique, along with the quality degradation it may induce, has been intentionally maintained, as it constitutes a key justification for the development and evaluation of alternative drying approaches, such as microwave-based methods.

Comment 3: The title of the paper is soybeans and line 62 is soybean grains. The form is not uniform. I hope it can be unified.

Answer: The term soybeans is used consistently throughout the revised version of the manuscript.

Comment 4: There is no literature support for lines 63-66, please supplement the literature.

Answer: An additional reference addressing the pre-soaking step prior to drying has been incorporated into the revised manuscript.

Comment 5: Lines 68-69 state that until a constant final weight was reached. What the final weight needs to be supported by data? please explain clearly.

Answer: The AOAC method indicates that the moisture content of the samples can be determined by oven drying, which is the procedure applied in this study. Further details can be found in the following reference:

-A.O.A.C. (1980). Official Methods of Analysis of the Association of Official Analytical Chemists, 17th ed., William Horwitz Ed.; Gaithersburg.

Comment 6: Line 80 states that it's 3.4 m/s for pumpkin seeds and 4.0 m/s for soybeans. Why use these two values? Is it compared with other data? If it is a comparison, please add the comparison data and references.

Answer: These values correspond to twice the minimum fluidization velocity for each of the selected food materials. The minimum fluidization velocity was estimated using the Ergun equation. The procedure can be found in the following reference:

-Kunii, D., & Levenspiel, O. (1991). Fluidization Engineering (2nd ed.). Butterworth-Heinemann.

This reference was added in the new version of the manuscript.

Comment 7: Is line 86 stating that 0 W is the control group? Please specify the control group of this paper.

Answer: The word control has been added in line 87

Comment 8: Soaked soybeans were used by line 91, the latter lacks literature support.

Answer: In order to operate the equipment using wet samples, a soaking step was applied as a pre-treatment. This approach has been previously reported in the literature.

- Ella ES, Dionisio-Sese ML, Ismail AM. Seed pre-treatment in rice reduces damage, enhances carbohydrate mobilization and improves emergence and seedling establishment under flooded conditions. AoB Plants. 2011; doi:10.1093/aobpla/plr007.

This reference was added in the new version of the manuscript

Comment 9: Line 111 (p > 0.05) can be written as (p> 0.05), and the rest of the paper also needs to be modified accordingly.

Answer: This was modified in the new version of the manuscript.

Comment 10: Please use lines of different colors to show differences between each group, such as Figure 2(a), Figure 3(a), etc.

Answer: The figures were modified following this suggestion.

Comment 11: Line 119 only mentions that pumpkin seeds go through a soaking step before drying, what about soybeans? The pretreatment of both materials before drying should be consistent.

Answer: Both samples were subjected to a soaking step prior to drying. The text in line 119 explains the observations shown in Figure 2, which corresponds to pumpkin seeds; therefore, it begins with this explanation.

Comment 12: Lines from139-160 say "soybeans", then say "pumpkin seeds", logic is unreasonable, please summarize and conclude again, placing reference [10] in its corresponding position at line147.

Answer: A new order has been adopted in this section to improve clarity. First, the behavior of pumpkin seeds is described, followed by that of soybeans.

Comment 13: Lines162-163 are suggested in previous statistical analysis.

Answer: These lines were improved in the new version of the manuscript (red color).

Comment 14: Line168 suggests using IRsoft v5 .2 software should be placed in previous statistical analysis.

Answer: IRsoft v5 .2 war removed from this line.

Comment 15: The moreover part of line183 suggests referring back to previous research methods.

Answer: this line was improved in the new version of the manuscript (red color).

Comment 16:  Please re-edit lines209 -231to make them concise and clear.

Answer: Conclusions section was improved following the suggestion of the revisor.

Comment 17: There are too few literatures in this paper, thus adding some excellent recent literatures would be necessary.

Answer: New references were added in the new version of the manuscript (red color).

Comment 18. Is this paper just experimental? What technical/economic challenges need addressing if scaling up industrial processing for soybeans and pumpkin seeds?

Answer: This work was previously presented at the 6^th Electronic Conference on Foods and reports the experimental results obtained during the drying of pumpkin seeds and soybeans. As correctly pointed out by the reviewer, the manuscript is strongly experimental in nature, with the primary objective of evaluating the performance of the prototype system and analyzing the combined effects of fluidization and microwave assistance on the drying process.

From a technical standpoint, scaling up the system will require a dedicated analysis of both the number and spatial arrangement of magnetrons. This is a non-trivial task, since microwave field distributions within a cavity are not random but depend strongly on cavity geometry and electromagnetic boundary conditions. The research group has prior experience in this type of electromagnetic modeling and calculation, which will allow this aspect to be addressed in future development stages.

Regarding fluidization, the results demonstrate that it plays a key role in preventing excessive temperature increases in the product, which is a highly desirable feature when drying heat-sensitive food materials. However, the level of fluidization must be carefully optimized in subsequent studies to limit the economic impact of the operation while preserving thermal stability.

Finally, the major forthcoming improvement of the prototype will be its automation and the implementation of real-time data acquisition systems. We consider these developments to be a crucial step toward the design and construction of industrial-scale equipment, enabling enhanced process control and facilitating future industrial implementation.

5. Additional clarifications:

The authors thank to the Revisor for the comments and suggestions to improve the manuscript.