The physical and chemical properties of pectin extracts obtained from different white and pink/red varieties of grapefruit [Citrus paradisi (Macf.)], using both conventional heating (CHE) and thermosonication (TS), were investigated. The content of galacturonic acid (GalA), degree of esterification (%DM), color and antioxidant capacity were analyzed. Fourier-Transform Infrared Spectroscopy (FTIR) associated with multivariate analysis enabled a structural comparison among the pectin extracts, and differential scanning calorimetry (DSC) completed a full landscape of the investigated extracts. Pectin extracts obtained by CHE showed mostly higher GalA than those obtained by TS. All the extracts had a high antioxidant capacity, as determined by 2,2 diphenyl 1-picrylhydrazyl (DPPH* ) and 2,2'-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS* +) assays, and a high correlation with the GalA content. The main differences observed in the FTIR spectra occurred in the 1200 to 900 cm-1 region (differences in GalA). The glass transition temperatures (Tgs) of all extracts were above 85 °C, making them interesting as stabilizing agents for the food industry. PRACTICAL APPLICATION A wide database for the characterization of pectin extracts from grapefruits was obtained. The relationship between the extraction method and the source of pectins, with the physicochemical and antioxidant properties provided great support for their application in the food industry.

中文翻译：

---

通过热处理和热超声表征从不同品种的粉红色/红色和白色葡萄柚 [Citrus Paradisi (Macf.)] 中提取的果胶

研究了使用常规加热 (CHE) 和热超声处理 (TS) 从不同的白色和粉红色/红色葡萄柚品种 [Citrus paradisi (Macf.)] 中获得的果胶提取物的物理和化学性质。分析了半乳糖醛酸(GalA)的含量、酯化度(%DM)、颜色和抗氧化能力。与多变量分析相关的傅里​​叶变换红外光谱 (FTIR) 使果胶提取物之间的结构比较成为可能，而差示扫描量热法 (DSC) 完成了所研究提取物的全貌。CHE获得的果胶提取物显示出比TS获得的大多更高的GalA。根据 2,2 二苯基 1-苦基肼 (DPPH* ) 和 2,2' 测定，所有提取物都具有高抗氧化能力 -Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) 二铵盐 (ABTS* +) 测定，与 GalA 含量高度相关。在 FTIR 光谱中观察到的主要差异发生在 1200 至 900 cm-1 区域（GalA 中的差异）。所有提取物的玻璃化转变温度 (Tgs) 均高于 85 °C，使其成为食品工业的稳定剂。实际应用 获得了用于表征葡萄柚果胶提取物的广泛数据库。提取方法与果胶来源、理化和抗氧化特性的关系为其在食品工业中的应用提供了很大的支持。在 FTIR 光谱中观察到的主要差异发生在 1200 至 900 cm-1 区域（GalA 中的差异）。所有提取物的玻璃化转变温度 (Tgs) 均高于 85 °C，使其成为食品工业的稳定剂。实际应用 获得了用于表征葡萄柚果胶提取物的广泛数据库。提取方法与果胶来源、理化和抗氧化特性的关系为其在食品工业中的应用提供了很大的支持。在 FTIR 光谱中观察到的主要差异发生在 1200 至 900 cm-1 区域（GalA 中的差异）。所有提取物的玻璃化转变温度 (Tgs) 均高于 85 °C，使其成为食品工业的稳定剂。实际应用 获得了用于表征葡萄柚果胶提取物的广泛数据库。提取方法与果胶来源、理化和抗氧化特性的关系为其在食品工业中的应用提供了很大的支持。