Impact of Drying Processes on the Nutritional Composition, Volatile Profile, Phytochemical Content and Bioactivity of Salicornia ramosissima J. Woods

Abstract

Salicornia ramosissima J. Woods is a halophyte plant recognized as a promising natural ingredient and will eventually be recognized a salt substitute (NaCl). However, its shelf-life and applicability in several food matrices requires the use of drying processes, which may have an impact on its nutritional and functional value. The objective of this study was to evaluate the effect of oven and freeze-drying processes on the nutritional composition, volatile profile, phytochemical content, and bioactivity of S. ramosissima using several analytical tools (LC-DAD-ESI-MS/MS and SPME-GC-MS) and bioactivity assays (ORAC, HOSC, and ACE inhibition and antiproliferative effect on HT29 cells). Overall, results show that the drying process changes the chemical composition of the plant. When compared to freeze-drying, the oven-drying process had a lower impact on the nutritional composition but the phytochemical content and antioxidant capacity were significantly reduced. Despite this, oven-dried and freeze-dried samples demonstrated similar antiproliferative (17.56 mg/mL and 17.24 mg/mL, respectively) and antihypertensive (24.56 mg/mL and 18.96 mg/mL, respectively) activities. The volatile composition was also affected when comparing fresh and dried plants and between both drying processes: while for the freeze-dried sample, terpenes corresponded to 57% of the total peak area, a decrease to 17% was observed for the oven-dried sample. The oven-dried S. ramosissima was selected to formulate a ketchup and the product formulated with 2.2% (w/w) of the oven-dried plant showed a good consumer acceptance score. These findings support the use of dried S. ramosissima as a promising functional ingredient that can eventually replace the use of salt.

Keywords: antioxidants; flavonoids; hypertension; minerals; volatile compounds.

Figure 1

Scheme of the analyses and bioactivity assays of the fresh, oven, and freeze-dried S. ramosissima.

Figure 2

Pie charts showing the chemical classes profile of volatile compounds of the S. ramosissima. (a) Volatile compounds profile of fresh plant; (b) volatile compounds profile of oven-dried plant; and (c) volatile compounds profile of freeze-dried plant.

Figure 3

Fresh, oven-dried, and freeze-dried extracts from S. ramosissima exerted antiproliferative effects in a dose-dependent manner after exposition for 24 h. Dose-response curves of the antiproliferative effect induced by the (a) freeze-dried extract, (b) oven-dried extract, and (c) fresh extract. (d) EC₅₀ values of the antiproliferative response induced by the fresh (EC₅₀ =15.82 ± 2.65 mg/mL), oven-dried (EC₅₀ = 17.56 ± 1.05 mg/mL), and freeze-dried (EC₅₀ = 17.24 ± 1.36 mg/mL) extracts in HT29 cells (cell model of CRC) did not show significant differences. Results shown are means of at least three independent experiments performed in triplicates ± SD. (*)represent the existence of statistical difference between that dose and the previous one, using one-way ANOVA for multiple comparisons by Tukey’s test (p < 0.05).

Figure 4

Evaluation mean scores for sensory attributes of the ketchups with 2.2% oven-dried S. ramosissima (2.2DS%) and 3.0% oven-dried S. ramosissima (3.0DS%) (n = 102 consumers). Each sensory attribute was evaluated using a nine-point hedonic scale where 1 = “disliked extremely” and 9 = “liked extremely”. The letters (a and b) correspond to the statistical analysis performed to calculate the existence of a significant difference (p < 0.05) between each sample according to the unpaired t-test.