Antioxidant and ACE-Inhibition Activities After In Vitro Digestion of a Non-Fermented Dairy Beverage Enriched with Postbiotics of Lactobacillus spp.

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This work studied the antioxidant, ACE-inhibition activities and antimicrobial effect after in vitro digestion of a non-fermented dairy beverage enriched with postbiotics of Lactobacillus acidophilus and Lactobacillus helveticus. However, the postbiotics produced by the two strains was not clear. The substrate and the products in vitro digestion were also not clear. The antioxidant activity was tested only by the in vitro methods, such as ABTS, DPPH, FRAP, and ORAC. It could not indicate the antioxidant activity in vivo scientifically. Besides, how about the relations of antimicrobial effect and antioxidant activity/ACE-inhibition activity. So, this work lacks of depth as well as novelty.

Author Response

Dear reviewer,
My comments are in the attached document.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

This manuscript presents insights into the effects of adding postbiotics to a dairy beverage on antioxidant, ACE inhibitory, and antimicrobial activities. While the manuscript has potential, several areas need to be improved before it can be accepted for publication in this journal. For instance, results on antioxidant activity from multiple methods are presented, but more discussion is needed to connect those results with each other. And promising results regarding ACE inhibitory activity with the postbiotic treatments are included, but further discussion is needed to highlight these results. Please see the attached for more specific comments.

Comments for author File: Comments.pdf

Author Response

Dear reviewer,
My comments are in the attached document.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

The study by Norma Angélica Bolivar-Jacobo et al., explores postbiotic supplementation in non-fermented dairy beverages, which is indeed a highly relevant and emerging topic in functional food research. Researchers have evaluated the antioxidant, antimicrobial, and ACE-inhibition activities, offering a holistic view of the health benefits of postbiotics. Furthermore, the experimental design is quite clear, including in vitro digestion simulations and statistical validation. Overall, the study is beneficial with sufficient novelty and can be accepted for publication after following modifications

1. The manuscript reports that postbiotics showed antimicrobial activity against Bacillus spp. and S. aureus but were ineffective against E. coli before and after digestion​. Were any mechanisms proposed to explain this selectivity? A discussion on why postbiotics lost their antimicrobial activity in the beverage matrix would improve clarity.
2. The manuscript states that postbiotics enhance ACE inhibition, but there is limited discussion on whether these effects are likely to translate into physiological benefits. Could more discussion on peptide stability and potential in vivo relevance be included?
3. The study notes a decrease in ACE inhibition after digestion. Are there strategies to enhance postbiotic stability in future formulations?
4. Some sections, particularly the graphs and tables, could benefit from better annotation. For instance, Figure 5 shows ACE inhibition but does not clearly explain differences between digestion phases​. Adding a brief explanation of key trends in the figure legends would help.
5. The statistical analysis mentions significance (p < 0.05), but a deeper discussion on the variability between trials would strengthen the conclusions.
6. Some sentences are lengthy and could be simplified for better readability.

Comments on the Quality of English Language

Quality of English is good

Author Response

Dear reviewer,
My comments are in the attached document.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

It can be accepted  in present form.

Reviewer 2 Report

Comments and Suggestions for Authors

Thank you. All comments were addressed, and the manuscript has been strengthened.