Faculty of Geoengineering, Department of Environmental Biotechnology, University of Warmia and Mazury in Olsztyn, Sloneczna St. 45G, 10-709, Olsztyn, Poland.
Faculty of Chemistry, Institute of General and Ecological Chemistry, Lodz University of Technology, Zeromskiego St. 116, 90-924, Lodz, Poland.
Sci Rep. 2022 Feb 25;12(1):3232. doi: 10.1038/s41598-022-07322-0.
Recovery of bioactive compounds from distillery waste could be an option for valorizing this waste. This study investigated how the extraction of polyphenols (which have antioxidant activity) from distillery stillage was affected by solvent type and concentration, extraction time, and method of extraction (conventional solid-liquid extraction, CSLE; ultrasound-assisted extraction, UAE; microwave-assisted extraction, MAE). Although recovery was similar with UAE and MAE, 3 min MAE with 80% ethanol and 80% methanol produced the highest yields of total phenolic content (TPC), total flavonoid content (TFC) and phenolic acids. With CSLE, TPC was 2.1-1.8-times lower than with MAE and 1.7-1.4-times lower than with UAE. Increasing the solvent concentration to 100% significantly decreased recovery. Six phenolic acids were recovered (ferulic and p-coumaric acid predominated), which were present mainly in the free form. There was a significant positive correlation between antioxidant activity, as measured with three methods (one based on the hydrogen atom transfer and two based on single electron transfer mechanisms), and phenolic acid content. With MAE and UAE, polyphenols were recovered more efficiently, with 2.1 times and 1.5 times higher antioxidant activity, and with 15 times and 9 times shorter extraction times, respectively, than with CSLE; thus, they can be considered "green" alternatives to CSLE.
从酿酒厂废料中回收生物活性化合物可能是实现废物增值的一种选择。本研究探讨了溶剂类型和浓度、提取时间以及提取方法（常规固液提取、超声辅助提取、微波辅助提取）对从酿酒厂酒糟中提取多酚（具有抗氧化活性）的影响。虽然超声辅助提取和微波辅助提取的回收效果相似，但 3 分钟的微波辅助提取，使用 80%乙醇和 80%甲醇，可获得最高的总酚含量（TPC）、总黄酮含量（TFC）和酚酸产量。与微波辅助提取相比，常规固液提取的 TPC 低 2.1-1.8 倍，TFC 低 1.7-1.4 倍。溶剂浓度增加到 100%会显著降低回收率。回收了 6 种酚酸（以阿魏酸和对香豆酸为主），主要以游离形式存在。三种方法（一种基于氢原子转移，两种基于单电子转移机制）测定的抗氧化活性与酚酸含量之间存在显著的正相关关系。与常规固液提取相比，超声辅助提取和微波辅助提取更有效地回收了多酚，其抗氧化活性分别提高了 2.1 倍和 1.5 倍，提取时间分别缩短了 15 倍和 9 倍；因此，它们可以被认为是常规固液提取的“绿色”替代方法。
