Effects of Drying and Extraction Methods on the Quality and Antioxidant Activity of Sea Buckthorn (Hippophae rhamnoides) Berries and Leaves

Abstract

Sea buckthorn is a promising source of bioactive compounds. However, there is limited information on the effect of post harvest drying and extraction of sea buckthorn on its antioxidant capacity. The effect of freeze, air, and solar dryingon the extraction yield of sea buckthorn berries and leaves was evaluated with respect to their bioactive content. Sequential extraction with solvents of different polarity and solvent-free microwave-assisted extraction were applied. Freeze-drying has better performance in the berries’ extracts, while air-drying has better performance in the leaves’ extracts. All data were analyzed by Multi Factor Analysis of Variance (ANOVA) and Duncan's post-hoc tests at a level of α = .05. Although the extraction yield in the sequential extraction of sea buckthorn berries is significantly better, the leaves’ extracts exhibit superior radical scavenging ability. Accelerated solar drying appears to preserve sea buckthorn leaves without degrading their antioxidant content. The components responsible for the high antioxidant activity of leaves’ extracts were found to be several flavonoids and polyphenols. The extract obtained by the microwave extraction of fresh berries exhibits moderate antioxidant activity compared to the polar extracts of freeze-dried berries.

Keywords:

• Air-drying
• Antioxidants
• Drying kinetics
• Freeze-drying
• Hippophae rhamnoides
• Microwave-assisted extraction
• Sea buckthorn
• Solar drying
• Solvent extraction

Notes

t_R : retention time.

[M + H]⁺: molecular ion adduct with H⁺.

CID's: Collision induced detection.

UV λ_max: ultraviolet maximum wave number.

t_R : retention time.

[M + H]⁺: molecular ion adduct with H⁺.

CID's: Collision induced detection.

UV λ_max: ultraviolet maximum wave number.

t_R : retention time.

[M + H]⁺: molecular ion adduct with H⁺.

CID's: collision induced detection.

UV λ_max: ultraviolet maximum wave number.