CO₂-responsive deep eutectic solvents for the enhanced extraction of hesperidin from Fertile orange peel

Hesperidin, also known as vitamin P, is widely studied for its distinctive potential in food and pharmaceutical industries. This work focuses on the research of CO₂-responsive deep eutectic solvents (DESs) used as recyclable extractants for efficient extraction of hesperidin from Fertile orange peel. Reversible phase transformation of DES solution was achieved by bubbling CO₂/N₂. The maximum extraction yield of 22.39 mg/g was obtained for hesperidin under the following conditions: DES-6 (triethanolamine: 4-methoxyphenol = 1:1) used as extractant, water content of 35 wt%, solid-liquid ratio of 1:60 g/mL, extraction temperature of 25 °C, and ultrasonic time of 25 min, which was much higher than that extracted by methanol. Hesperidin of 74.38% was recovered in top phase after CO₂ triggering. Density function theory (DFT) results indicated that hydrogen and π-π bonds were the main factors affecting hesperidin extraction. This study provides a new idea for extracting natural bioactive compounds using recyclable extractants.