Effects of Dairy Cows Management Systems on the Physicochemical and Nutritional Quality of Milk and Yogurt, in a North-Eastern Romanian Farm

Round 1

Reviewer 1 Report

Title: Effects of Dairy Cows Management Systems on the Physicochemical and Nutritional Quality of Milk and Yogurt, in a North-Eastern Romanian Farm

Journal: Agriculture

Manuscript ID: agriculture-2451190

The given information in this manuscript is useful for researchers and academia and the article would be a good contribution to the discipline of food technology and especially the dairy industry. However, I think the room for improvement is always there and I have suggested some major revisions;

-      Lines 211 and 217: The time needed for milk pasteurization in order to yogurt preparation is incorrect. In addition, the isoelectric point of caseins is pH=4.6 and the inoculated milk must keep at 43-44 °C until reaches the mentioned pH.

-      Lines 237 and 241: The methods for determining pH and titratable acidity of yogurt samples must be modified. The equation for the calculation of titratable acidity is incorrect. The correct equation for the calculation of titratable acidity (% LA) is as follows:

Titratable acidity (%) = vol. 0.1 NaOH (mL) × 0.1 × 0.09 × 100 / mass of sample (g)

I recommend the following article for correction of the methods for yogurt preparation and pH and titratable acidity analysis:

Say, D., Soltani, M., & Guzeler, N. (2019). Physical, chemical, and microstructural properties of nonfat yogurts fortified with the addition of tara gum alone or in combination with buttermilk powder. Journal of Food Processing and Preservation, 43(11), e14217.

-      Lines 490-491: The sentence is incomprehensible. Please rewrite.

-      Line 490-497: The level of starter culture is the same for different yogurt samples. Please identify the reason for the difference between the yogurts in terms of hardness based on the differences in the compositions of milks.  

-      Line 498: Please provide the reason for the cohesiveness difference between yogurt samples using relevant references.

-      Line 500-501: Use relevant references for the definition of cohesiveness.

-      Lines 524-525: Use relevant reference/s.

 

 

 

·       Please improve the English language for a better flow of literature.

 

·       Please recheck the manuscript and remove grammatical mistakes.

Author Response

Honorable reviewer,

 

First of all I want to thank you for the time allocated to the work. I also thank you for the remarks made and I want to let you know that I have taken everything into account, making the changes in the work.

 

Lines 211 and 217: The time needed for milk pasteurization in order to yogurt preparation is incorrect. In addition, the isoelectric point of caseins is pH=4.6 and the inoculated milk must keep at 43-44 °C until reaches the mentioned pH. 

 

Pasteurization of the milk was done at a temperature of 85 - 90°C for 20 - 30 minutes after which the milk was cooled to a temperature of 43°C at which time the cultures were added. The milk was then homogenized and then dosed in plastic cups and placed in the thermostat. With the thermostat, the times and temperature are set automatically, the parameters we used were: 43°C for 360 min, 20°C for 90 minutes, 15°C for 60 minutes and at 6°C for 100 minutes. Storage was done at 4-5°C.

 

Lines 237 and 241: The methods for determining pH and titratable acidity of yogurt samples must be modified. The equation for the calculation of titratable acidity is incorrect. The correct equation for the calculation of titratable acidity (% LA) is as follows:

 

Titratable acidity (%) = vol. 0.1 NaOH (mL) × 0.1 × 0.09 × 100 / mass of sample (g) 

I recommend the following article for correction of the methods for yogurt preparation and pH and titratable acidity analysis:

Say, D., Soltani, M., & Guzeler, N. (2019). Physical, chemical, and microstructural properties of nonfat yogurts fortified with the addition of tara gum alone or in combination with buttermilk powder. Journal of Food Processing and Preservation, 43(11), e14217.

 

I have changed the method used for both pH and acidity to your recommendation.

 

Lines 490-491: The sentence is incomprehensible. Please rewrite.

 

Proteins, mainly casein, interact with cultures of lactic acid bacteria to form a gel-like structure, giving yogurt its characteristic texture. When the milk has a higher protein content, the value recorded for hardness is higher.

 

Line 490-497: The level of starter culture is the same for different yogurt samples. Please identify the reason for the difference between the yogurts in terms of hardness based on the differences in the compositions of milks.

The samples' YGC hardness levels were therefore greater than YCS due to the fact that the protein level was higher in the milk used for its manufacture.

 

Line 498: Please provide the reason for the cohesiveness difference between yogurt samples using relevant references.

 

This might be associated to the higher levels of protein content, which result in denser sample structures. Our findings support previous studies that have been reported by Lucatto et al., (2019)

and Al-Bedrani et al., (2023).

 

 

Bibliography

 

(1)      Lucatto, J. N.; Silva-Buzanello, R. A.; Mendonça, S. N. T. G.; Lazarotto, T. C.; Sanchez, J. L.; Bona, E.; Drunkler, D. A. Performance of Different Microbial Cultures in Potentially Probiotic and Prebiotic Yoghurts from Cow and Goat Milks. Int. J. Dairy Technol. 2020, 73 (1), 144–156. https://doi.org/10.1111/1471-0307.12655.

(2)      Al-Bedrani, D. I. J.; ALKaisy, Q. H.; Rahi, A. K.; Saadi, A. M. Evaluation of Milk Source on Physicochemical, Texture, Rheological and Sensory Properties of Yogurts. J. Appl. Nat. Sci. 2023, 15 (1), 128–136. https://doi.org/10.31018/jans.v15i1.4269.

 

Line 500-501: Use relevant references for the definition of cohesiveness.

 

Cohesiveness measures how effectively a product resists a second deformation in comparison to its resistance under the first deformation (Bourne, 2002).

 

Bourne, M. C. (2002). Food texture and viscosity: Concept and measurement. In Academic

Press ((2end ed.).). Elsevier Science & Technology Books. https://doi.org/10.1016/B978-0-12-417044-5.00058-5.

 

 

Lines 524-525: Use relevant reference/s.

 

Author Response File: Author Response.docx

Reviewer 2 Report

I have reviewed the manuscript entitled "Effects of Dairy Cows Management Systems on the Physicochemical and Nutritional Quality of Milk and Yogurt, in a North-Eastern Romanian Farm", submitted to Agriculture Special Issue "Animal Nutrition and Productions: Series II". The manuscript aimed to investigate changes in the fatty acid composition of cow milk of Romanian Spotted cows' husbandry and feeding systems. Also, the influence of raw milk quality on yogurt quality was evaluated.

 

I believe that the manuscript is very interesting but needs some minor revisions.

 

L161: Was microbiological quality (TBC) and hygienic quality (SCC) tested in the milk? Has the condition of the udder been checked?

 

L163-165: In what temperature and how long was the milk stored before

transport?

 

L212: Please correct and write "bulgaricus" with a lowercase letter.

 

L215: What was the capacity or dimensions of the plastic cups? Please

complete this data. Were texture measurements taken directly in these cups?

 

L219: What was the temperature of the yogurts when the texture was measured? Please complete.

 

Table 2-6: In each table, "Moment of analysis" would be worth replacing with another wording, such as the research date, the experimental period, or the season.

 

L316-319, and other captions below tables: Wasn't it better to use the notation that "averages with different letters in the rows/columns indicate statistically significant differences..."?

 

L429, 525: Please add a period at the end of the sentence.

 

Most of the cited literature sources are more recent than the last five years, but their choice is appropriate.

Author Response

Honorable reviewer,

 

First of all I want to thank you for the time allocated to the work. I also thank you for the remarks made and I want to let you know that I have taken everything into account, making the changes in the work.

 

L161: Was microbiological quality (TBC) and hygienic quality (SCC) tested in the milk? Has the condition of the udder been checked?

The milk is checked regularly for total germs count by the company that collects milk for processing, for total germs count and was found below 50000 germs / ml and also for somatic cells count and was found always below 160000 SC / ml, while the en force regulations states a maximal threshold of 100000 germs/ml and 400000/ml for somatic cells. We did not run ourselves the checks to have sufficient repetitions in order to present them as statistical data. Udder health status was right, as the SCC was below the threshold. If these thresholds are exceeded the milk is confiscated by the veterinary authority and it was not the case.

 

L163-165: In what temperature and how long was the milk stored before transport?

          The milk was stored in storage tanks secured with a homogenizing paddle at a temperature of 4°C. There are maximum 14 hours between milk collections. Separate tanks were used for each type of milk. The yogurt was processed from the milk collected at the evening milking and that from the morning milking being transported in a car equipped with a milk tank. The temperature of the milk during the transport was 5°C.

 

L212: Please correct and write "bulgaricus" with a lowercase letter.

I made the change

 

L215: What was the capacity or dimensions of the plastic cups? Please complete this data. Were texture measurements taken directly in these cups?

The capacity of the glasses used for yogurt was 250 ml (diameter 65 mm and height 108 mm). The determinations were performed directly in the glass in order not to destroy the clot. The cylindrical probe used for texture was matched to the diameter of the glass so that the distance from the probe to the wall of the glass was 13 mm.

 

L219: What was the temperature of the yogurts when the texture was measured? Please complete.

The storage temperature was 4 degrees, they were analyzed for texture immediately after they were taken out of the refrigerator. For all analyzed samples, the temperature was 4±1°C. 

 

Table 2-6: In each table, "Moment of analysis" would be worth replacing with another wording, such as the research date, the experimental period, or the season.

I made the change

 

L316-319, and other captions below tables: Wasn't it better to use the notation that "averages with different letters in the rows/columns indicate statistically significant differences..."?

I made the change

 

L429, 525: Please add a period at the end of the sentence.

I made the change

 

Most of the cited literature sources are more recent than the last five years, but their choice is appropriate.

 

 

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

Dear authors

Thank you for implementing the requested corrections.

Sincerely...