Nutritional Composition and Bioactive Properties of Salicornia brachiata: A Comparison of Drying Methods

Abstract

Objective Salicornia brachiata, an euhalophyte thriving in saline environments, can be processed into a dried powder (termed bio-salt) from its tender aerial parts. This study aimed to evaluate how three distinct drying methods; freeze-drying (FD), microwave-vacuum drying (MVD) as low temperature drying methods, and heat pump oven drying (HPOD) as a high temperature drying method, affect nutritional composition and bioactivities of S. brachiata. Ultimately, this research aims to identify the most suitable drying approach that retains bioactive and nutritional properties to preserve the health benefits of bio-salt. Methods The aerial parts of S. brachiata were washed, air-dried overnight, and then subjected to various drying methods. The proximate composition, colour measurements, mineral composition, and microbial quality of the dried powders were evaluated. The lipid extracts were analyzed using GC-MS and the total phenolic content and antioxidant activity of the resulting powders were assessed. Results Among the methods, FD best preserved the plant's color and yielded the highest levels of carbohydrates (42.64%), crude fat (0.88%), and dietary fibers (29.72%). Methanolic extracts of FD powders exhibited the highest phenolic content (43.68 ± 0.04 mg GAE/g DW) and superior antioxidant activity, with IC50 values of 8.72 ± 0.50 µg/mL for the DPPH assay and 19.49 ± 0.76 µg/mL for the ABTS assay, outperforming both MVD and HPOD. The FD extracts contained a higher proportion of unsaturated fatty acids compared to saturated fatty acids. In vitro antibacterial assays revealed that the FD extract at 100 mg/mL demonstrated the strongest inhibition against test bacteria. In an anti-inflammatory assay, FD was identified as the most effective drying method, yielding the lowest IC50 value of 314.78 ± 1.55 µg/mL. Conclusion These results suggest that freeze-drying is the most suitable drying method for preserving the bioactive properties and health benefits of bio-salt derived from the aerial parts of S. brachiata.