**4. Conclusions**

The results of the present study showed a significant effect of plant parts and harvesting stages on the nutritional value and chemical composition of purslane. Leaves contained higher amounts of macronutrients than stems, especially at 52 DAS, while α-tocopherol was the main vitamin E isoform, which increased at 52 DAS resulting in the highest overall tocopherol content. Glucose and fructose were the main sugars in stems and leaves, respectively, while stems contained higher amounts of total sugars in comparison to leaves. Regarding oxalic acid as well as total organic acids, the highest contents were recorded in leaves, especially at the last harvesting stage (52 DAS). The edible plant parts contained both omega-6 and omega-3 fatty acids, although leaves were more abundant in α-linolenic acid than stems, which contained mostly palmitic and linoleic acids. Phenolic compounds and oleracein derivatives were also detected in plant parts, with oleraceins A and C being the main compounds detected in leaves, regardless of harvesting stage. In conclusion, early harvesting and the separation of plant parts could increase the nutritional value of the final product through increasing the content of valuable compounds, such as omega-3 fatty acids, phenolic compounds and oleracein derivatives, while at the same time, the contents of anti-nutritional compounds such as oxalic acid are reduced.

**Author Contributions:** S.A.P. conceived and designed the research, administered and supervised the project, carried out the cultivation, wrote the original draft and reviewed and edited the final manuscript; Â.F. performed chemical analyses, data curation, and methodology; M.I.D performed chemical analyses, data curation, and methodology; I.B.V. carried out the cultivation and prepared the original draft; K.P. carried out the cultivation and prepared the original draft; L.B. performed chemical analyses, data curation, and methodology, wrote the original draft and reviewed and edited the final manuscript; I.C.F.R.R. administered the project, obtained funding, administered and supervised the project, reviewed and edited the final manuscript.

**Funding:** The authors are grateful to the Foundation for Science and Technology FCT, Portugal and FEDER under Programme PT2020 for financial support to CIMO (UID/AGR/00690/2019). Â.F., M.I.D., and L.B. thank the national funding by FCT, P.I., through the institutional scientific employment program-contract for their contracts. The authors are also grateful to the FEDER-Interreg España-Portugal program for financial support through the project 0377\_Iberphenol\_6\_E.

**Conflicts of Interest:** The authors declare no conflict of interest.
