Structural Characterization and In Vitro Antioxidant Activity of a Novel Polysaccharide from Summer-Autumn Tea

Area of Science:

• Food Science
• Biochemistry
• Phytochemistry

Background:

• Summer-autumn tea is underutilized.
• Polysaccharides are known for their health benefits.
• Investigating tea polysaccharides can reveal new functional ingredients.

Purpose of the Study:

• To isolate and characterize a water-soluble polysaccharide (D1N1) from summer-autumn tea.
• To evaluate the antioxidant activity of D1N1.
• To explore the potential of D1N1 as a functional food ingredient.

Main Methods:

• Hot water extraction, ethanol precipitation, and column chromatography for isolation.
• Spectroscopic and chromatographic techniques (UV, FTIR, HPAEC, GC-MS, NMR) for structural elucidation.
• In vitro antioxidant assays (DPPH, superoxide anion radical, ABTS+ radical scavenging).

Main Results:

• A water-soluble polysaccharide, D1N1, was successfully isolated.
• D1N1 is predominantly composed of glucose (95%), with minor amounts of galactose, arabinose, and rhamnose.
• The molecular weight of D1N1 was determined to be 224.71 kDa, with a specific linkage pattern and branching.
• D1N1 exhibited significant free radical scavenging activity.

Conclusions:

• The structural characterization of D1N1 provides insights into its composition and linkage.
• D1N1 possesses notable antioxidant properties.
• These findings support the application of summer-autumn tea polysaccharide as a functional food ingredient.