该研究建立了苹果皮多酚超声辅助天然低共熔溶剂（Natural Deep Eutectic Solvent, NADES）提取工艺，分析了NADES作用机理。对比六种NADES与φ=80%甲醇提取的苹果皮多酚含量、抗氧化活性确定氯化胆碱-乙二醇（Choline Chloride-Ethylene Glycol, ChCl-EG, 1:4）为最佳提取溶剂，单因素结合正交优化其工艺为料液比1:50（g/mL），含水率30%，提取时间50 min，提取温度60 ℃，所得提取物总酚含量和DPPH、ABTS+自由基清除活性及铁离子还原能力分别为33.16 mg GAE/g DW、52.60、38.30和30.76 mg TE/g，均显著高于80%甲醇提取物，且较优化前分别提高了160.69%、122.41%、138.04%、102.37%，表明ChCl-EG可高效提取苹果皮多酚。采用UPLC-MS/MS从ChCl-EG和甲醇提取物共鉴定17个酚类化合物，二者主要成分一致。NMR氢谱表明ChCl和EG分子间形成了氢键，FT-IR分析显示ChCl-EG与提取物分子间氢键作用力强于甲醇。真实溶剂类导体屏蔽模型分析显示ChCl-EG与多酚分子结合性能更佳，溶解能力和相互作用能分别是甲醇的1.39和1.12倍，从分子层面阐释了ChCl-EG高效作用机理。该研究结果为苹果皮多酚绿色提取工艺及NADES高效作用机理研究提供了科学参考。

The extraction process of polyphenols from apple peels by ultrasound-assisted natural deep eutectic solvent (NADES) was established, and the mechanism of NADES was analyzed. After evaluating the polyphenol content of apple peel and antioxidant activity extracted with six NADES and 80% methanol, choline chloride-ethylene glycol (ChCl-EG, 1:4) was identified as the optimal extraction solvent. The process was optimized using single factor and orthogonal experiments, resulting in a solid-liquid ratio of 1:50, a water content of 30%, an extraction duration of 50 min, and an extraction temperature of 60 °C. The extract exhibited significantly higher levels of total phenolic content (TPC), DPPH, ABTS+ free radical scavenging activity, and the ferric ion reducing antioxidant power at 33.16 ± 0.43 mg GAE/g DW and 52.60, 38.30, and 30.76 mg TE/g, respectively, compared to the 80% methanol extracts. These values experienced significant increases of 160.69%, 122.41%, 138.04%, and 102.37%, respectively, following the optimization process. These results indicate that ChCl-EG can extract polyphenols efficiently from apple peels. A total of 17 phenolic compounds were identified from ChCl-EG and methanol extracts using UPLC-MS/MS, with the primary components being consistent. NMR hydrogen spectrum revealed the formation of hydrogen bonds between ChCl and EG molecules. FT-IR analysis indicated that the hydrogen bonding interactions between ChCl-EG and extract molecules was stronger compared to that of the methanol extracts. The analysis of the conductor-like screening model for real solvents (COSMO-RS) revealed that ChCl-EG exhibited superior binding properties with apple polyphenols, with the solubility and interaction energy being 1.39 and 1.12 times those of methanol, respectively. This elucidates the efficient mechanism of ChCl-EG at the molecular level. The results of this study provide a scientific basis for the green extraction technology of polyphenols from apple peel and the efficient mechanism of NADES.

民族地区生态环境国家民委重点实验室自主课题（中央民族大学）（KLEEMA202205）