In this study, eco-friendly deep eutectic solvents (DESs) were used as extracting agents for the first time in the extraction of pectins from mango peel. Two novel green solvents including betaine-citric acid (Bet-CA) and choline chloride-malic acid (ChCl-MaA) were screened, and the extraction conditions were further optimized by full factor design experimental along with RSM. In addition, ultrasound treatment also had an influence on extraction yield, structural and physicochemical properties of extracted pectins. Two DES-extracted pectins had significantly higher yield, larger molecular weight and particles size than HCl-extracted pectin. High intensity ultrasound power enhanced the yield of low-ester pectins, but decreased the molecular weight and particles size of the pectins extracted. Monosaccharide compositions analysis showed that higher content of galacturonic acid (GalA) and larger HG region were observed in two DESs-extracted pectins. Fourier transform infrared spectra (FT-IR) of all pectins extracted were similar, with slight differences. Two DESs-extracted pectins exhibited higher DE values than HCl-extracted pectin. Thermal analysis and zeta potential results showed that HCl-extracted pectin had better stability than ChCl-MaA-extracted pectin. Additionally, HCl-extracted pectin had higher viscosity properties than two DESs-extracted pectins or commercial pectin (CP). Moreover, it was found that HCl-extracted pectin was in a colloid state, while two DESs-extracted pectins or CP were in a flow state. Ultrasound treatment significantly improved the yields of pectin/low-ester pectin. Additionally, ultrasound treatment remarkably decreased the viscosity and viscoelastic properties of the pectins extracted. The results were conducive to our understanding of the relationship between extraction conditions and physicochemical properties of the pectins extracted, which provides theoretical basis for the functional application of mango peel pectins in the food and pharmaceutical industry.

本研究首次使用环保型深共熔溶剂（DESs）作为萃取剂从芒果皮中提取果胶。筛选出甜菜碱-柠檬酸（Bet-CA）和氯化胆碱-苹果酸（ChCl-MaA）两种新型绿色溶剂，通过全因子设计实验和RSM进一步优化提取条件。此外，超声处理对提取果胶的提取率、结构和理化性质也有影响。与 HCl 提取的果胶相比，两种 DES 提取的果胶具有显着更高的产率、更大的分子量和更大的粒径。高强度超声功率提高了低酯果胶的产量，但降低了提取果胶的分子量和粒径。单糖成分分析表明，在两种 DESs 提取的果胶中观察到较高含量的半乳糖醛酸 (GalA) 和较大的 HG 区域。提取的所有果胶的傅里叶变换红外光谱 (FT-IR) 相似，略有差异。两种 DESs 提取的果胶表现出比 HCl 提取的果胶更高的 DE 值。热分析和zeta电位结果表明，HCl提取的果胶比ChCl-MaA提取的果胶具有更好的稳定性。此外，HCl 提取的果胶比两种 DES 提取的果胶或商业果胶 (CP) 具有更高的粘度特性。此外，发现 HCl 提取的果胶处于胶体状态，而两种 DES 提取的果胶或 CP 处于流动状态。超声处理显着提高了果胶/低酯果胶的产量。此外，超声处理显着降低了提取的果胶的粘度和粘弹性。研究结果有助于我们了解提取条件与提取的果胶理化性质的关系，为芒果皮果胶在食品和医药行业的功能应用提供理论依据。