# Sea Purslane as an Emerging Food Crop: Nutritional and Biological Studies
## 3 Results and Discussion
### Mineral and Heavy Metal Composition  
Due to the saline environment, halophytes, in general, have higher contents in minerals than other edible plants [41]. The mineral content of _H. portulacoides_ leaves, obtained by atomic absorption spectrometry, is shown in Table 2.  
The intake of minerals provided by 100 g of fresh leaves of _H. portulacoides_ was estimated from the average RNIs (Recommended Nutrient Intakes) for adult females and males in the European Union (when applicable) (adapted from [42; 43; 44; 45]). The most abundant minerals were sodium, potassium, calcium, magnesium, and phosphorus, followed by iron, manganese, zinc, copper, and iodine with minor concentration. Phosphorus, calcium, magnesium, sodium, potassium, and iron are essential minerals for human health [37]. Zinc, copper, manganese, chromium, and nickel are necessary in residual concentrations in the human diet [37]. In general, a distinctive property of the halophyte plant is its exceptionally high sodium content. In fact, the amount of sodium in fresh leaves of _H. portulacoides_ is around 1.8% (raw matter). The sodium consumption per day should not exceed 2300 mg [46] and, consequently, the intake of 100 g of fresh _H. portulacoides_ corresponds to 78% of the daily value recommended for sodium. Sodium is considered an essential nutrient, but its excessive consumption is associated with several pathologies such as hypertension and cardiovascular disease [4]. Hence, the sodium concentration in leaves is acceptable for human intake, but special care must be taken to not exceed the daily dose recommended by the FDA [46]. The content of sodium (8.19 g/100 g, dry matter) was similar to the value 7.82 g/100 g (dry matter) found by [PERSON] et al. [9] for leaves of _H. portulacoides_ and _Salicornia_ species (Table 3), which are succulent shoots highly appreciated in gourmet cuisine due to their salty taste. The level of sodium accumulation in plant tissues depends on the availability of elemental nutrients concentrations, namely nitrogen, in saline environments [22; 47]. Potassium and calcium are other minerals in high concentration in this plant, respectively, 1433.64 and 764.77 mg/100 g (dry matter). In dry matter, the potassium concentration in leaves of _H. portulacoides_ was similar to that in _Salicornia bigelowii_ but much higher than _Sarcocornia perennis alipini_ or _Salicornia ranossissima_[48]. Leaves of _H. portulacoides_ presented much higher calcium contents than _Sarcocornia_ and _Salicornia_ species (Table 3). Amongst the halophyte plants, the _H. portulacoides_ plant is a good source of calcium and potassium. Copper, zinc, and iron are essential micronutrients necessary in chloroplast reactions, enzyme systems, protein synthesis, and hormone growth [49]. Iron is an essential mineral and cofactor in the synthesis of neurotransmitters, as well as an important constituent of proteins involved in oxygen transport and metabolism [19]. Concentrations of iron (9.92 mg/100 g of dried matter) in leaves of sea purslane are similar to the halophyte _Salicornia bigelowii_ Torr [48]. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Composition** & **Raw Matter** & **Intake Provided by 100 Fresh** \\  & **mg/100 g** & **Leaves (\%)** \\ \hline Sodium, Na & 1799.38 \(\pm\) 13.98 & 78.0 \\ Potassium, K & 314.97 \(\pm\) 0.89 & 9.5 \\ Calcium, Ca & 168.02 \(\pm\) 0.63 & 24.0 \\ Magnesium, Mg & 67.24 \(\pm\) 0.29 & 28.0 \\ Phosphorus, P & 40.41 \(\pm\) 1.58 & 7.3 \\ Iron, Fe & 2.18 \(\pm\) 0.15 & 7.6 \\ Manganese, Mn & 1.51 \(\pm\) 0.04 & 73.7 \\ Zinc, Zn & 0.64 \(\pm\) 0.05 & 7.8 \\ Copper, Cu & 0.21 \(\pm\) 0.02 & 16.8 \\ lodine, I & 0.011 \(\pm\) 0.004 & 7.3 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Mineral composition (mg/100 g raw matter) and the mineral intake (%) provided by 100 g of fresh leaves of _H. portulacoides_. Zinc concentration in _H. portulacoides_ leaves (2.93 mg/100 g in dry matter) is higher than the value reported by [PERSON] et al. (1.94 mg/100 g in dry matter) [50].