Yogurt Enriched with Isochrysis galbana: An Innovative Functional Food

Round 1

Reviewer 1 Report

This manuscript contains data and findings which are worthy of publication, particularly with regard to the use of ethyl acetate and impact on profile of lipid classes and the effects on  bioaccessibility compared to the use of whole microalgal biomass. However the style of writing is 'long-winded' and the manuscript   will be greatly improved when the style of English is improved throughout and results and discussion are presented in a more succinct and direct manner, and over-repetition of certain phrases, such as those beginning "Concerning....   

The introduction is otherwise sufficient in content and methods used by the authors are clearly described. However information on the culture conditions and production methods used in providing the biomass tested should be supplied to back up the results and discussion regarding the lipid classes and fatty acid profiles. This is important because the authors discuss how culture conditions etc will change the biomass composition and profile of lipids. Absence of this information is a weakness.

Results and Discussion should be reduced in length, by both reducing the extent of repetition of data in the text which is already presented in tables and figures and using a much more succinct writing style.  

P10: the authors incorrectly cite [32] to rationalise the high content of FFA they observed, stating "The same author suggests that FFA accumulation may be a way for the cell to prevent the reduction of molecular oxygen and consequent generation of ROS".  In [32] Li et al demonstrate nicely and conclude correctly that "a function of TAG synthesis following N deprivation ...is to relieve "a detrimental overreduction of the photosynthetic electron transport chain." This is in fact a well-known phenomenon.  Li et al refer to TAG, not FFA. Discussion of the high levels of observed FFA needs to be reconsidered in light of both the culture conditions and production methods used to provide the biomass tested in the manuscript.  

Author Response

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Author Response File: Author Response.docx

Reviewer 2 Report

            The aim of the research falls within the thematic scope of the journal.

            The purpose of this study was to formulate a functional food by the incorporation of the microalga Isochrysis galbana (in form of freeze-dried biomass or its ethyl acetate lipidic extract), as value-added food ingredients in the yoghurt in order to increase ω3 LC-PUFAs content, but also investigate the bioaccessibility of ω3 LC-PUFAs from the functional yogurts using an in vitro model of human digestion.

The topic seems to be interesting. The manuscript is generally well prepared but requires some adjustments.

Below are some comments and suggestions for changes that came after reading the manuscript submitted for review.

Basic objections and comments:

1. In this type of research, the sensory evaluation of new products should be carried out and its results presented in the manuscript
2. Why the Authors decided to add 2% and not another - was it due to nutritional reasons? from sensory reasons? from the reasons of the relevant literature data?
3. The statistical analysis in which the Authors compared the results which, in my opinion, should not be compared, raises reservations; the results for biomass yoghurt versus yoghurt with extract versus control yoghurt should be analyzed.

All remarks (including minor ones which are not mentioned here) are marked in the text of manuscript in the review mode.

Comments for author File: Comments.pdf

Author Response

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Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

The authors took into account most of my comments, others - commented. The only change that they could introduce is the one contained in Point 2 - in the Authors' response to the review there is a fragment that can be introduced into the manuscript in the appropriate place, that is:

"The microalga incorporation level of 2 % (w/w) was chosen based on the literature available over microalgal biomass incorporation into food products (Gouveia et al., 2008; Fradique et al., 2013; Batista et al., 2017)."

In its current form, the manuscript may be subject to further processing. 

Author Response

Please see the attachment.

Author Response File: Author Response.docx