Salt stress applied to hydroponically cultivated Atriplex portulacoides 2-weeks before harvesting modulates the lipid composition, enhancing their nutritional and bioactive properties

Halophytes are gaining popularity as gourmet plant foods for human consumption due to their attractive organoleptic and nutritional characteristics. They can be sustainably cultivated hydroponically, offering a significant advantage over wild harvesting by allowing the improvement of nutritional and functional qualities through modulated cultivation conditions. This study aimed to determine the optimal harvesting time for hydroponically produced Atriplex portulacoides, cultivated at a reference salinity of 20 and with short-term saline stress (2 and 4-weeks, salinities of 30, 35, and 40). The lipid content, fatty acid (FA), and lipidome profiles of the aerial organs of the plant were evaluated using GC–MS and LC-MS, and antioxidant properties were assessed using DPPH and ABTS assays. The results showed that 4-weeks of saline stress at a salinity of 35 resulted in the highest lipid content. Two weeks of saline stress at a salinity of 30 produced a FA profile with the highest content of the omega-3 polyunsaturated FA C18:3 n-3 and the lowest content of saturated C16:0. Two weeks of saline stress at a salinity of 35 resulted in lipid extracts with the best health-promoting lipid indexes (hypocholesterolemic/hypercholesterolemic, atherogenic, and thrombogenic indexes). The lipidome signature also differed between groups, with samples exposed to 2-weeks of salinity stress at 30 and 35 exhibiting higher content of TG, PL, and GL esterified with polyunsaturated FA. Lipid extracts with higher antioxidant activity were achieved with samples from the 2-week salinity stress at 30 and 35. Overall, A. portulacoides cultivated with a 2-week salinity stress at salinities of 30 and 35 had the best nutritional value and bioactive properties compared to other conditions tested. These results suggest that short-term salt stress applied to hydroponically cultivated A. portulacoides modulates the composition of lipids present on the aerial organs of the plant, enhancing nutritional and bioactive properties, increasing production value, and promoting this halophyte as an alternative and sustainable food ingredient.