# Effect of Cooking Methods on Bioactive Pigments in Purple Carrots (_Daucus carota_ L.)
## 4 Conclusions  
The procedure used during cooking had a deep impact on the content of the beneficial-to-health pigments and free radical scavenging activity of purple carrots. Freeze-drying resulted in the increase of polyphenols including anthocyanins, but it led to the loss of carotenoids. On the contrary, both boiling and steaming caused an increase of carotenoids, although only boiling resulted in significant losses of polyphenols. Roasted carrots, however, exhibited a more balanced result. On the one hand, roasting did not result in particularly high contents of either carotenoids or polyphenols, but on the other hand, no relevant losses of any of the studied pigments were observed. This fact has also been reported in other purple-pigmented foods [31]. The content of polyphenols correlated directly with the free radical scavenging activity of purple carrots, while a direct correlation between carotenoids and the antioxidant capacity was not observed. This reveals that polyphenols, mainly anthocyanins, are the main contributors to the AA of purple carrots, whatever the cooking method used. Overall, freeze-dried and roasted purple carrots exhibited higher AA than carrots subjected to boiling and/or steaming. However, each cooking method possesses advantages and drawbacks in such a way that the selection of one or another will depend, to a great extent, on the sought objective.  
In view of the results of this work, the purpose now is to study in depth the effect of roasting on purple carrots. For that purpose, new variables such as the influence of moisture and type of oven, together with heating time and temperature, will be considered. In addition, vitamins, aroma compounds and sensorial evaluation will also be included. Future studies estimating the antioxidant and anti-inflammatory properties of the digested fractions after cooking are also scheduled.  
Conceptualization, G.P.B. and M.L.R.d.C.; methodology, L.S.-E., G.P.B. and M.L.R.d.C.; formal analysis, L.S.-E. and G.P.B.; investigation, L.S.-E., G.P.B. and M.L.R.d.C.; data interpretation, L.S.-E., G.P.B. and M.L.R.d.C.; bibliographic search, L.S.-E., G.P.B. and M.L.R.d.C.; writing--original draft, M.L.R.d.C.; writing--review and editing, L.S.-E., G.P.B. and M.L.R.d.C.; supervision, M.L.R.d.C.; funding acquisition, G.P.B. All authors have read and agreed to the published version of the manuscript.  
This work was supported by the Comunidad of Madrid and European funding from FSE and FEDER programs (project S2018/BAA-4393, AVANSECAL-II-CM).  
Not applicable.  
The data that support the findings of this study are available from the corresponding author upon reasonable request.  
We are grateful to [PERSON] for his help in performing the heat treatment of the samples and the Analysis Service Unit facilities of ICTAN for the use of the common equipment.  
The authors declare no conflict of interest.  
\begin{table}
\begin{tabular}{c c c} \hline
**Total Pigment Content/AA Assay** & **Linear Regression Equation** & **Coefficient (r2)** \\ \hline TCC/DPPH & y = \(-218.41\)x +1857.6 & 0.3457 \\ \hline TCC/ABTS & y = \(-266.86\)x + 1855.8 & 0.3449 \\ \hline TPC/DPPH & y = \(456.76\)x \(-29.47\) & 0.9994 \\ \hline TPC/ABTS & y = \(558.78\)x \(-26.36\) & 0.9995 \\ \hline TAC/DPPH & y = \(58.089\)x \(-11.85\) & 0.9936 \\ \hline TAC/ABTS & y = \(71.012\)x \(-11.47\) & 0.9940 \\ \hline \end{tabular}
\end{table}
Table 5: Correlation by linear regression between total pigment contents and AA.