Key Laboratory of Food Processing Technology and Quality Control in Shandong Province, College of Food Science and Engineering, Shandong Agricultural University, Tai'an, 271018, China; School of Engineering, University of Guelph, Guelph, ON N1G 2W1, Canada.
School of Engineering, University of Guelph, Guelph, ON N1G 2W1, Canada.
Carbohydr Polym. 2020 Aug 1;241:116272. doi: 10.1016/j.carbpol.2020.116272. Epub 2020 Apr 26.
This work investigates the effect of drying okra pods by different techniques [freeze-drying (FD), sun-drying (SD), oven-drying (OD) and microwave-drying (MD)] on the molecular structure, physicochemical and antioxidant properties of the subsequently extracted OP. Remarkably, although the degree of methyl esterification (∼41.1 %) remained similar among samples, the content of galacturonic acid (62.67-68.77 %), average number molecular weight (MnI: 758.8-808.5 kDa, MnII: 20.9-24.2 kDa), and to a greater extent the apparent viscosity of an aqueous solution of pectin molecules, water holding capacity (0.21-10.71 g/g) and emulsifying activity (42.3-72.7 %) and stability (38.6-53.5 %), decreased with the drying temperature in the order of FD-OP > SD-OP > OD-OP > MD-OP. On the other hand, only FD-OP presented a higher proportion of galactan and/or arabinan side chains [(Ara + Gal) / Rha = 12.37%] compared to the rest of the samples, with values ranging from 7.79 to 9.17%. FD-OP and SD-OP resulted in lower DPPH and ABTS radical scavenging activities.
这项工作研究了不同干燥技术（冷冻干燥（FD）、晒干（SD）、烘培干燥（OD）和微波干燥（MD））对随后提取的 OP 分子结构、物理化学和抗氧化特性的影响。值得注意的是，尽管样品之间的甲酯化程度（~41.1%）相似，但半乳糖醛酸（62.67-68.77%）、平均分子量（MnI：758.8-808.5 kDa，MnII：20.9-24.2 kDa）的含量，以及更大程度上的果胶分子水溶液的表观粘度、持水能力（0.21-10.71 g/g）和乳化活性（42.3-72.7%）和稳定性（38.6-53.5%），随着干燥温度的升高而降低，顺序为 FD-OP > SD-OP > OD-OP > MD-OP。另一方面，与其余样品相比，只有 FD-OP 具有更高比例的半乳糖和/或阿拉伯聚糖侧链[(Ara + Gal) / Rha = 12.37%]，其值范围为 7.79%至 9.17%。FD-OP 和 SD-OP 的 DPPH 和 ABTS 自由基清除活性较低。
