Development of a Quantitative Colour-Based Software Method to Evaluate the Effectiveness of Active Antioxidant Packaging on Fresh Sliced Mushrooms

Round 1

Reviewer 1 Report

The article entitled Development of a quantitative colour-based software method to evaluate the effectiveness of active antioxidant packaging on fresh sliced mushrooms proposes new method for distinguishing changes in appearance of mushroom after they were treated with different substances in order to prolong their shelf life.  In the introduction, authors claim that the usual colorimetric apparatus is not sensitive enough which I strongly disagree. Can you explain why those methods are not sensitive enough. In the text you speak about the colour difference whereas you measured only lightness cannot say anything about the colour but measuring only lightness. How was the visual comparison test performed? What were the viewing conditions? In Fig 2 there are only lightness values after 8 days. Where are the initial values?

Figure 3: How were the images captured (digital camera, smartphone?) Why mixing blank and protected samples in various time frames. There is no use in comparing those pictures.

The authors have to address these issues, and accordingly rewrite the article.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

Must include some results in the abstract section.

There must be problem statement and objectives modules under the heading of the Introduction for a better understanding of the proposed research.

Please include the Discussion by comparing the proposed and existing approaches along with their reference.

Please elaborate conclusion and must be relevant to the proposed research.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

The authors made some changes, but major points are still questionable. Again, there is a statement that spectrophotometers are not sensitive enough which is not true. Also, authors still speak about the colour difference whereas they measured only lightness.  Colour difference implies all three coordinates, L, a and b. And the calculated value between original and treated mushrooms, dE.

Figure 3: Why mixing blank and protected samples in various time frames. There is no use in comparing those pictures.

The authors have to address these issues, and accordingly rewrite the article.

Author Response

NOTE: in addition to the track changes, to improve the readability and localization of the modifications, they have been highlighted in green background in the revised version of the manuscript.

Point 1: The authors made some changes, but major points are still questionable. Again, there is a statement that spectrophotometers are not sensitive enough which is not true. Also, authors still speak about the colour difference whereas they measured only lightness. Colour difference implies all three coordinates, L, a and b. And the calculated value between original and treated mushrooms, dE.

Response 1: We regret that the first revision was not completely satisfactory. On this occasion, any reference to limitations in terms of spectrophotometer sensitivity has been removed. Only the limitations of other simpler techniques, such as digital cameras, are mentioned. The text has been modified as follows:

“The more sophisticated methods described in the literature, such as imaging spectrographs, acousto-optical tunable filters (AOTF), 3CCD cameras, or liquid crystal tunable filters (LCTF) can provide excellent results, but expensive and complex apparatus are required [16–19]. On the other hand, cheaper and simpler approaches, like the use of digital cameras have been considered [20] but in the case of mushrooms, limited capabilities for determining subtle changes of colour have been reported.”

Regarding the three color coordinates and the final CIELAB based on L* only, the reviewer is correct and the statement has been clarified. The following text, as well as a new reference [22] (the rest of them has been updated accordingly, including the number of pages that was accidentally omitted in the previous version) has been added in section 2.4:

“In particular, only the lightness value, L*, was considered, since this colour coordinate has been reported as the most relevant one [22], when assessing mushroom browning.”

In addition, to eliminate any doubt, the paragraph corresponding to section 2.5.1 CIE L*a*b*, has been reworded as follows:

“As previously mentioned, despite all the colour coordinates were measured, only the lightness value (L*) of the surface of mushrooms excluding the area of gills was considered for each sample.”

Finally, the former title of section 3.1. CIE L*a*b* has been changed to “L* measurements” and the paragraph begins now with “The obtained results of L* are shown…”.

Note: According to the changes made, and the elimination of a* and b* from the equation, the calculation of DE commented by the reviewer, which considers the three coordinates, is now meaningless, so it has not been included in the article.

Point 2: Figure 3: Why mixing blank and protected samples in various time frames. There is no use in comparing those pictures.

Response 2: According to the reviewer's comment, the figure has been modified, presenting now all images corresponding to samples at 8 days from the beginning of the experiment. In particular, images c) and e), initially corresponding to 1-day blank samples, have been replaced by active packaging samples (green tea + a-tocopherol) after 8 days, thus effectively eliminating comparisons between different time frames.

Consequently, the beginning of the caption has been changed to:

“Figure 3. Comparison of different mushroom samples, all of them collected after 8 days: a) image of a sample protected with green tea + a-tocopherol; b) image of a blank sample; c) scan of a sample protected with green tea + a-tocopherol; d) scan of a blank sample after 8 days; e) segmenta-tion of a sample protected with green tea + a-tocopherol; f) segmentation of a blank sample.”

We appreciate the suggestion, and hope that it will now be more useful and clearer for the readers and will be perceived in this way by the reviewer.

Point 3: The authors have to address these issues, and accordingly rewrite the article.

Response 3: We greatly appreciate the reviewer’s comments and hope that, this time, the changes introduced and the explanations will be satisfactory.

Author Response File: Author Response.pdf