Effect of Supplied Salt Concentrations in the Nutrient Solution during Hydroponic Production on Phytochemicals and Antioxidant Activity of Ice Plants (Mesembryanthemum crystallinum L.)

Abstract

The research aimed to evaluate the effects of different salt concentrations (0, 10, 30, 50, 70, and 100mM NaCl) applied during the cultivation process on the levels of phytochemical components (polyphenols, flavonoids, tannins, saponins, and alkaloids), color compounds (chlorophyll a, chlorophyll b, total chlorophyll, and carotenoids), and antioxidant activity (DPPH and FRAP) in ice plants. The monitoring showed that ice plants grew well at salt concentrations between 30 and 100mM NaCl, without any visible negative effect. As salt concentration increased, the levels of bioactive compounds, color compounds, and antioxidant activity also increased. However, the appropriate salt concentration should be selected based on the intended use of the ice plant; For pharmaceutical or cosmetic applications, a concentration of 100mM NaCl is recommended, as it maximizes the accumulation of bioactive compounds, color compounds, and antioxidant capacity. Specifically, the ice plant contained polyphenols at 205.22mgGAE/100g FW, flavonoids at 32.02mgQE/100g FW, tannins at 62.74mgTAE/100g FW, saponins at 162.34mgSE/100g FW, and alkaloids at 234.02mgCE/100g FW. The total chlorophyll and carotenoids content were 11.74mg/g FW and 0.57mg/g FW. The antioxidant activities measured by DPPH and FRAP were 75.74% and 73.72mM FeSO4/100g FW, respectively. If the ice plant is intended for consumption as a food vegetable, a lower salt concentration of 30-70mM NaCl is recommended, as excessive salt accumulation in the plant could affect its taste and consumer health.