de Faria Daliane Cláudia, de Queiroz Maria Eliana Lopes Ribeiro, Novaes Fábio Junior Moreira
Departamento de Química, Universidade Federal de Viçosa, Campus Universitário, Avenida Peter Henry Rolfs, s/n, Viçosa 36570-900, MG, Brazil.
Plants (Basel). 2025 Jan 11;14(2):185. doi: 10.3390/plants14020185.
Soxhlet extraction is a method recommended by the Association of Official Analytical Chemists (AOAC) to determine the lipid content in plant samples. Generally, n-hexane (toxicity grade 5) is used as the solvent (≈300 mL; ≈30 g sample) at boiling temperatures (69 °C) for long times (≤16 h) under a chilled water reflux (≈90 L/h), proportionally aggravated by the number of repetitions and samples determined. In this sense, the technique is neither safe nor sustainable for the analyst or the environment. This article presents the development of an alternative and more sustainable procedure for determining the lipid content in raw Arabica coffee beans. A 3 full factorial design was used to perform direct hot solid-liquid extractions in 4 mL vials, varying the ground grains and solvent ratios, temperatures, and times. An optimal condition resulted in an extractive yield statistically equivalent to Soxhlet, without variation in the composition of the oil fatty acids determined by GC-MS after hole oil transesterification. This procedure was presented as a sustainable alternative to Soxhlet extraction because it does not require water for cooling and needs a smaller volume of solvent (2 mL) and sample mass (0.2 g); it also has a smaller generated residue, as well as requiring a shorter time (1.5 h) and less energy expenditure for extraction.
索氏提取法是美国官方分析化学家协会（AOAC）推荐的一种用于测定植物样品中脂质含量的方法。一般来说，正己烷（毒性等级5）在沸腾温度（69℃）下用作溶剂（约300毫升；约30克样品），在冷水回流（约90升/小时）下长时间（≤16小时）使用，提取次数和测定的样品数量会相应增加。从这个意义上讲，该技术对分析人员或环境而言既不安全也不可持续。本文介绍了一种用于测定生阿拉比卡咖啡豆中脂质含量的替代且更具可持续性的方法。采用三因素全因子设计，在4毫升小瓶中进行直接热固液萃取，改变研磨颗粒与溶剂的比例、温度和时间。优化条件下的萃取产率在统计学上与索氏提取法相当，全油酯交换后通过气相色谱 - 质谱联用仪（GC - MS）测定的油脂肪酸组成没有变化。该方法被认为是索氏提取法的一种可持续替代方法，因为它不需要水冷却，所需溶剂量较少（2毫升）和样品量较少（0.2克）；产生的残渣也较少，并且提取所需时间较短（1.5小时）和能量消耗较少。
