Some Plant Food Products Present on the Polish Market Are a Source of Vitamin B12
Round 1
Reviewer 1 Report
The authors investigated the amount of B12 contained in some fermented vegetable products. Sea buckthorn jam and pickled parsley juice contain B12, which is useful information. On the other hand, most fermented vegetable products did not contain B12, but the data that B12 is not included is also useful. However, the method of preparing the sample has not been fully shown.
Since B12 in food is often bound to protein, the apparent amount of B12 in unheated samples is low. The authors did not boil samples when measuring B12 in those.
In addition to cyanocobalamin, foods also contain adenosylcobalamin, methyl cobalamin, and hydroxocobalamin. These cannot be measured by our method.
Minor point
There is a typo in the title of Table 1.
All "traces" in Table 1 should be in lowercase
The authors should indicate the SD value.
How many times was each sample measured?
In line 161, the unit is different from Table 2.
The authors should write “Supplemtaru Materials” and “Author contributions” correctly.
Author Response
Adjustments were marked in yellow
Thank you for your interesting remarks concerning methodology. We assumed that Food Chemistry journal (5-year IF = 6.219) is a reliable source of analytical methods and scientific information. Thus, we took HPLC method from Nakos M., Pepelanova I., Beutel S., Krings U., Berger R.G., Scheper T. Isolation and analysis of vitamin B12 from plant samples, Food Chemistry. Since it was published in 2017 and we wanted to compare our results to those obtained in their paper we applied the same method.
As for other remarks:
Ad. 1 and Ad. 2 We have improved the typos, both in the title of Table 1 and in "traces"
Ad. 3 Thank you for pointing out the lack of SD value. They were added to both the amount of vitamin B12 in the sea buckthorn jam (table 1) and the amount of vitamin B12 in the pickled parsley juice (table 2).
Ad. 4 During the analyzes, each of the samples was analysed twice (line 129).
Ad. 5 Thank you for pointing to the typo. The unit has been corrected for the correct one.
Ad. 6 We have accidentally omitted these paragraphs. The paragraph "Supplementary Materials" has been deleted, and the "Author Contributions" has now been properly completed.
Reviewer 2 Report
Jedut et al. investigated whether some plant food products sold on the Polish market (sauerkraut, fermented cucumbers, parsley juice, beetroot juice, and white borscht) are a potential source of Vitamin B12. They detected cyanocobalamin using the HPLC-UV method. The main finding was that Only sea-buckthorn jam and pickled parsley juice could provide the amount of vitamin B12 needed to prevent deficiency. Although others performed previous similar studies, this is an extended version and includes a broader range of potential sources of vitamin B12. While I find this paper interesting, I have some comments and suggestions for the authors:
- The authors mention that Lactic acid bacteria are naturally present in the human digestive system and manifest the ability to synthesize B vitamins. Yet, they did not discuss the possibility of producing pseudo vitamin B12 by, e.g., Lactobacillus reuteri (https://doi.org/10.1016/j.febslet.2007.09.012). Moreover, do you think that the analysis performed is sufficient to differentiate true and pseudo vitamin B12?
- What is the limit of detection in μg·kg-1 (experiment: content of cyanocobalamin in solid samples of fermented vegetable products). It states only the μg·l-1 LOD. In line 161, the units are μg·kg-1, while the table states μg·l-1. Please check the consistency of the units.
- Table 1 (line 152) + Table 2 (line 155): only mean without SD is presented (sea buckthorn jam 100% - Table 1; pickled parsley juice – Table 2).
- This reviewer believes that recommending consuming these products as a good source of vitamin B12 is beyond the scope of this work since no bioavailability test was performed (and also - see comment 1). Is there any work related to the bioavailability of vitamin B12 from plants, and specifically these widely consumed products?
- Line 188 – it was published recently that the vitamin B12 in the Spirulina algae might be mainly pseudo and not a bioavailable form. Other plant sources might be better vitamin B12 sources (https://doi.org/10.3390/nu12103067).
- Line 65: Lactobacillus reuteri should be in Italic
- Line 102: Hippophae rhamnoides L should be in Italic.
- Line 178: Lentinula edodes should be in Italic.
Author Response
Adjustments were marked in green
Ad. 1 Thank you very much for pointing out this aspect. We added the suggested study to Introduction. In our opinion, the analysis carried out is sufficient to distinguish true vitamin B12 from pseudovitamin B12, because the standard that we used to prepare the standard curve was pure cyanocobalamin. The retention time of the analyzed samples was in agreement with that of the standard at the same wavelength of 361 nm.
Ad. 2 The units of Limit of Detection and Limit of Quantitation have been changed to µg · kg-1 (line 148).
Ad. 3 Thank you for pointing out the lack of SD value. Appropriate corrections were made.
Ad. 4 This fragment has been removed. Unfortunately there is a lack of research on the bioavailability of vitamin B12 from fermented plant products analyzed in this study.
Ad. 5 Thank you so much for this information. We added this product in our manuscript as a valuable source of vitamin B12.
Ad. 6, Ad. 7, Ad. 8 Thank you for pointing out the error, the result of text formatting. These names have already been corrected using italic.
Round 2
Reviewer 1 Report
The authors made significant changes and additions to the manuscript, which is now much improved and answered all the questions and remarks to a satisfactory degree.
