Department of Chemical Engineering, Faculty of Sciences, University of Vigo, Edificio Politécnico, As Lagoas s/n, 32004 Ourense, Spain.
EPF-School of Engineering, 21 Boulevard Berthelot, 34000 Montpellier, France.
Molecules. 2021 Oct 23;26(21):6402. doi: 10.3390/molecules26216402.
is a plant rich in phenolics and other bioactive compounds. Their leaves are discarded as waste in the maqui berry industry. A new application of these wastes is intended by the recovery of bioactive compounds using pressurized hot water extraction with conventional or microwave heating. Both technologies have been selected for their green character regarding the type of solvent and the high efficiency in shorter operation times. Extractions were performed in the temperature range 140-200 °C with a solid/liquid ratio of 1:15 (). The extracts' total phenolic content, antioxidant capacity, and saccharides content obtained with both heating methods were measured. Additionally, the thermo-rheological properties of the gelling matrix enriched with these extracts were analyzed. Optimum conditions for lyophilized extracts were found with conventional heating, at 140 °C and 20 min extraction; 250.0 mg GAE/g dry extract and 1321.5 mg Trolox/g dry extract. Close to optimum performance was achieved with microwave heating in a fraction of the time (5 min) at 160 °C (extraction), yielding extracts with 231.9 mg GAE/g dry extract of total phenolics and antiradical capacity equivalent to 1176.3 mg Trolox/g dry extract. Slightly higher antioxidant values were identified for spray-dried extracts (between 5% for phenolic content and 2.5% for antioxidant capacity). The extracts obtained with both heating methods at 200 °C contained more than 20% oligosaccharides, primarily glucose. All the formulated gelling matrices enriched with the obtained extracts displayed intermediate gel strength properties. The tested technologies efficiently recovered highly active antioxidant extracts, rich in polyphenolics, and valuable for formulating gelling matrices with potential applicability in foods and other products.
马基莓是一种富含酚类化合物和其他生物活性化合物的植物。在马基莓产业中，其叶子通常被当作废物丢弃。本研究旨在通过使用加压热水提取法，从这些废物中回收生物活性化合物，实现其新的应用。常规加热和微波加热这两种技术均因其使用的溶剂类型环保，以及在更短的操作时间内实现高效率而被选中。在 140-200°C 的温度范围内，固液比为 1:15()，进行了提取实验。使用这两种加热方法测量了提取物的总酚含量、抗氧化能力和糖含量。此外，还分析了富含这些提取物的凝胶基质的热流变特性。使用常规加热，在 140°C 下提取 20 分钟，可得到最佳的冻干提取物条件，得率为 250.0 mg GAE/g 干提取物和 1321.5 mg Trolox/g 干提取物。在微波加热下，在更短的时间（5 分钟）内于 160°C 进行提取，也可达到接近最佳的性能，得到的提取物总酚含量为 231.9 mg GAE/g 干提取物，自由基清除能力相当于 1176.3 mg Trolox/g 干提取物。喷雾干燥提取物的抗氧化值略高（酚含量高 5%，抗氧化能力高 2.5%）。在两种加热方法下于 200°C 得到的提取物中，含有超过 20%的低聚糖，主要是葡萄糖。用所获得的提取物富马酸的所有配方凝胶基质均显示出中等凝胶强度特性。这两种测试技术均能有效地回收高活性抗氧化提取物，其富含多酚，可用于配制具有潜在应用价值的凝胶基质，例如在食品和其他产品中。
