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Valorization of Cork Using Subcritical Water.
Mónica Cunha1, Ana Lourenço1, Susana Barreiros1
1LAQV-REQUIMTE, Chemistry Department, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal.
Molecules (Basel, Switzerland)
|October 17, 2020
Summary
Subcritical water extraction of cork yields more phenolics at lower temperatures (up to 120°C) and more carbohydrates at higher temperatures (120-200°C). Suberin structure remained unaffected by this process.
Area of Science:
- Biomass valorization
- Green chemistry
- Sustainable materials
Background:
- Cork is a sustainable raw material with potential applications.
- Subcritical water extraction offers an environmentally friendly method for biomass processing.
- Understanding the impact of temperature on cork extract composition is crucial for targeted applications.
Purpose of the Study:
- To investigate the effect of temperature on subcritical water extraction of granulated cork.
- To analyze the composition (carbohydrates and phenolics) of cork extracts obtained at different temperatures.
- To evaluate the antioxidant activity of the extracts.
Main Methods:
- Granulated cork was treated using subcritical water extraction/hydrolysis in a semi-continuous reactor.
- Extractions were performed at temperatures ranging from 120°C to 200°C at a constant pressure of 100 bar.
- Extract composition, yield, and antioxidant activity were analyzed.
Main Results:
- Extraction yield increased with temperature, attributed to changes in water properties (dielectric constant, ionic product).
- Extracts up to 36% phenolics with notable antioxidant activity were obtained at temperatures up to 120°C.
- Higher temperatures (120-200°C) yielded extracts richer in carbohydrates, with approximately 20% phenolics in larger quantities.
- Suberin content and structure remained unchanged throughout the process.
Conclusions:
- Subcritical water extraction allows tunable extraction of cork components by adjusting temperature.
- Lower temperatures favor phenolic extraction, while higher temperatures enhance carbohydrate recovery.
- This method provides a sustainable route for producing valuable cork-derived compounds without altering suberin integrity.
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