Ultrasonic-assisted extraction using a betaine-based natural deep eutectic solvent for resveratrol extraction from melinjo (Gnetum Gnemon) seeds

Objective: Melinjo (Gnetum gnemon L.) seeds are known to contain resveratrol, which are classified as a phenolic compound of the stilbenoid. Melinjo seeds have high water content, making them unstable to be stored for prolonged periods with open packaging at room temperature. The present study aimed to explore the use of ultrasonic-assisted extraction with a betaine-based natural deep eutectic solvent (NADES) for resveratrol extraction from irradiated melinjo seeds. Methods: The best betaine-based NADES component was identified among betaine-urea, betaine-lactic acid, and betaine-malic acid. Optimization of extraction methods was performed using the best NADES and extraction variables such as time of extraction, water percentage, and sample: solvent ratio. The outcome of extraction was evaluated by measuring resveratrol content using high-performance liquid chromatography and the results were analyzed using response surface methodology. Results: The best betaine-based NADES was found to be betaine-lactic acid, yielding a resveratrol content of 0.3344 mg/g powder. The optimum extraction was achieved in 10 min with 60% water and a sample: solvent ratio of 1:10, yielding a resveratrol content of 0.227 mg/g powder Conclusion: Betaine-based NADES can be purposed as an alternative solvent for resveratrol extraction from irradiated melinjo seeds.