Department of Physics, Thomas Jefferson University, East Falls Campus, Philadelphia, PA 19144, USA.
Department of Chemistry and Biochemistry, Thomas Jefferson University, East Falls Campus, Philadelphia, PA 19144, USA.
Molecules. 2022 Aug 11;27(16):5124. doi: 10.3390/molecules27165124.
Nanotechnology has become increasingly important in modern society, and nanoparticles are routinely used in many areas of technology, industry, and commercial products. Many species of nanoparticle (NP) are typically synthesized using toxic or hazardous chemicals, making these methods less environmentally friendly. Consequently, there has been growing interest in green synthesis methods, which avoid unnecessary exposure to toxic chemicals and reduce harmful waste. Synthesis methods which utilize food waste products are particularly attractive because they add value and a secondary use for material which would otherwise be disposed of. Here, we show that spent coffee grounds (SCGs) that have already been used once in coffee brewing can be easily used to synthesize gold and silver NPs. SCGs derived from medium and dark roasts of the same bean source were acquired after brewing coffee by hot brew, cold brew, and espresso techniques. The total antioxidant activity (TAC) and total caffeoylquinic acid (CQA) of the aqueous SCG extracts were investigated, showing that hot brew SCGs had the highest CQA and TAC levels, while espresso SCGs had the lowest. SCG extract proved effective as a reducing agent in synthesizing gold and silver NPs regardless of roast or initial brew method.
纳米技术在现代社会中变得越来越重要，纳米颗粒在技术、工业和商业产品的许多领域中经常被使用。许多种类的纳米颗粒（NP）通常使用有毒或有害的化学物质合成，这使得这些方法不太环保。因此，人们越来越关注绿色合成方法，这些方法避免了对有毒化学品的不必要暴露，并减少了有害废物的产生。利用食品废物产品的合成方法特别有吸引力，因为它们为原本要丢弃的材料增加了价值和二次利用。在这里，我们表明，已经在咖啡酿造中使用过一次的用过的咖啡渣（SCG）可以很容易地用于合成金和银纳米颗粒。从中度和深度烘焙的同一种咖啡豆来源获得的经过热泡、冷泡和意式浓缩咖啡冲泡后的 SCG。研究了水性 SCG 提取物的总抗氧化活性（TAC）和总咖啡酰奎宁酸（CQA），结果表明，热泡咖啡渣的 CQA 和 TAC 水平最高，而意式浓缩咖啡渣的水平最低。无论烘焙程度或初始冲泡方法如何，SCG 提取物在合成金和银纳米颗粒方面都被证明是一种有效的还原剂。
