柑橘果胶的酸法提取工艺及其理化性质与应用

Citrus Pectin Acid Extraction Process, Physicochemical Properties, and Applications

摘要:

为了解柑橘果胶的提取工艺-结构特征-应用性能的关系，拓展不同性能果胶的精准应用场景，提高柑橘加工副产物的应用价值。该研究采用酸提法从柑橘加工副产物-果渣中提取果胶，以果胶得率、酯化度、凝胶强度等作为关键评估指标，以优化柑橘果胶的应用品质。结果表明，最优提取温度为72.00 ℃、提取pH值为1.75、提取时间为4.50 h。在此条件下，果胶平均得率为25.70%、平均酯化度为71.97%、平均凝胶强度为253.00 g/cm2。果胶的质构关系分析表明，当果渣分子量在30.0×104 g/mol以上、粘度在7.0 dL/g以上，半乳糖醛酸含量在82%~88%时，柑橘果胶具备更好的酯化度和凝胶性能（酯化度>70.00%，凝胶强度>230.00 g/cm2），这与完整的分子链结构、高酯化度与结晶位点和高半乳糖醛酸含量有关。同时，果胶的低蛋白沉淀率（<0.50%）与分子量、侧链结构和酯化度等有关。提取工艺与原料差异导致了果胶结构特征的变化，又进一步影响了果胶的应用性能和活性功能。因此，深入了解提取工艺和原料性能对果胶产品的影响，对于开发优质果胶成品和筛选果胶原料具有重要意义。

Abstract:

The relationship between the citrus pectin extraction process, its structural characteristics, and performance remain poorly understood. To address this gap in knowledge and enhance the value of citrus processing by-products, precise application scenarios for pectin with varying properties were analyzed. An acid extraction method was used to extract pectin from the citrus processing by-product pomace. Pectin yield, degree of esterification, and gel strength were evaluated as key indicators to optimize the application quality of citrus pectin. The optimal extraction conditions were as follows: 72.00 ℃, pH of 1.75, and an extraction time of 4.50 h. Under these conditions, the average pectin yield was 25.70%, the average esterification degree was 71.97%, and the average gel strength was 253.00 g/cm2. The textural relationship analysis of pectin indicated that when the molecular weight of the pomace was >30.0×104 g/mol, viscosity was >7.0 dL/g, and the galacturonic acid content was 82%~88%, the pectin exhibited a favorable degree of esterification and gel performance (degree of esterification >70.00% and gel strength >230.00 g/cm2), which were associated with a complete molecular chain structure, a higher number of esterification and crystallization sites, and a higher galacturonic acid content. The low protein precipitation rate of the pectin (<0.50%) was related to its molecular weight, side chain structure, and degree of esterification. Variations in the extraction processes and raw materials lead to changes in the structural characteristics of pectin, thereby affecting its application performance and functional activity. Elucidating the influence of extraction processes and raw material properties on pectin products is crucial for developing high-quality pectin products and selecting suitable pectin raw materials.