Department of Chemical, Environmental and Materials Engineering, Universidad de Jaén, Campus Las Lagunillas, Jaén 23071, Spain.
Department of Chemical, Environmental and Materials Engineering, Universidad de Jaén, Campus Las Lagunillas, Jaén 23071, Spain.
Food Chem. 2020 Jun 1;314:126218. doi: 10.1016/j.foodchem.2020.126218. Epub 2020 Jan 16.
Olive leaves farmed from trees are valuable for the production of functional extracts. Nonetheless, olive leaves (containing thin branches), which are separated during olives cleaning in the mill, have received little attention. In this context, a multiple response optimization was performed to maximize at once the yield, total phenolic content, oleouropein and antioxidant activity obtained by ultrasound-assisted extraction of this low-cost byproduct. The optimum was achieved using the following operational parameters: solid-to-liquid ratio, 5.9%; ethanol concentration, 47%; extraction time, 50 min. This enabled to obtain an extract with both high level of oleuropein and antioxidant activity. Besides oleuropein, other minor phenolic compounds were characterized in the extract, which could contribute to the antioxidant activity as Pearson correlation suggested. After this extraction step, how the phenolic extraction affects the recovery/profile of other constituents was evaluated, looking for the integral valorization of this resource towards the zero-waste.
橄榄叶由树木种植，对于功能性提取物的生产具有重要价值。然而，橄榄叶（含有细枝）在橄榄清洗过程中会被分离，因此很少受到关注。在这种情况下，进行了多次响应优化，以同时最大化超声辅助提取这种低成本副产物的产率、总酚含量、橄榄苦苷和抗氧化活性。最佳条件为：固液比 5.9%，乙醇浓度 47%，提取时间 50 分钟。这使得可以获得具有高橄榄苦苷和抗氧化活性的提取物。除了橄榄苦苷，提取物中还鉴定出了其他一些微量酚类化合物，如皮尔逊相关性分析所示，这些化合物可能有助于抗氧化活性。在这一步提取之后，评估了酚类提取物对其他成分回收/分布的影响，旨在实现对这种资源的整体增值，达到零浪费的目标。
