Méndez Daniel Alexander, Fabra María José, Gómez-Mascaraque Laura, López-Rubio Amparo, Martinez-Abad Antonio
Food Safety and Preservation Department, Institute of Agrochemistry and Food Technology (IATA-CSIC), 46980 Valencia, Spain.
Interdisciplinary Platform for Sustainable Plastics towards a Circular Economy-Spanish National Research Council (SusPlast-CSIC), 28006 Madrid, Spain.
Foods. 2021 Mar 31;10(4):738. doi: 10.3390/foods10040738.
Watermelon is the second largest fruit crop worldwide, with great potential to valorise its rind waste. An experimental design was used to model how extraction parameters (temperature, pH, and time) impact on the efficiency of the process, purity, esterification degree, monosaccharide composition and molar mass of watermelon rind pectin (WRP), with an insight on changes in their structural properties (linearity, branching degree and extraction severity). The models for all responses were accurately fitted (R > 90%, lack of fit ≥ 0.05) and experimentally validated. At optimum yield conditions, WRP yield (13.4%), purity (540 µg/g galacturonic acid) and molar mass (106.1 kDa) were comparable to traditional pectin sources but showed a higher branching degree with longer galactan side chains and a higher protein interaction. Harsher conditions (pH 1) generated purer homogalacturonan fractions with average molar masses (80 kDa) at the expense of yield, while mild extraction conditions (pH ≥ 2) produced highly branched entangled pectin structures. This study underlines novel compositional features in WRP and the possibility of producing novel customized pectin ingredients with a wider potential application scope depending on the targeted structure.
西瓜是全球第二大水果作物，其瓜皮废弃物具有很高的利用价值。采用实验设计来模拟提取参数（温度、pH值和时间）对西瓜皮果胶（WRP）提取过程效率、纯度、酯化度、单糖组成和摩尔质量的影响，并深入了解其结构特性（线性、分支度和提取强度）的变化。所有响应模型均拟合良好（R>90%，失拟度≥0.05）并通过实验验证。在最佳产率条件下，WRP的产率（13.4%）、纯度（540µg/g半乳糖醛酸）和摩尔质量（106.1 kDa）与传统果胶来源相当，但具有更高的分支度，半乳聚糖侧链更长，蛋白质相互作用更强。更苛刻的条件（pH 1）会以产率为代价生成纯度更高的同型半乳糖醛酸级分，平均摩尔质量为（80 kDa），而温和的提取条件（pH≥2）会产生高度分支的缠结果胶结构。本研究强调了WRP的新组成特征，以及根据目标结构生产具有更广泛潜在应用范围的新型定制果胶成分的可能性。
