Green emerging extraction technologies to obtain high-quality vegetable oils from nuts: A review

The high oil content of nuts and its fatty acid profile with biological proprieties positively affect blood lipids and lipoproteins. Nuts are low in saturated and high in unsaturated fatty acids (MUFA and PUFA) and are rich sources of other essential nutrients. Vegetable oils extraction is usually done through conventional methods like Soxhlet, cold-pressed Bligh, and Dyer methods. These methods are easy to perform, but they present several disadvantages, mainly related to environmental pollution and long extraction times. Therefore, emerging and green extraction technologies such as supercritical/subcritical, ultrasound, microwave, and enzyme-assisted extractions have been developed and were revised in this paper, showing relevant advantages over traditional methods. These technologies are environmentally friendly, allow the reduction of extraction time, the extraction yields are usually not very different from the obtained with conventional methods, and allow getting oils of better quality, which are less susceptible to oxidation processes. • In general, emerging technologies lower extraction time and energy consumption. • Compounds, like tocopherols and phytosterols are usually better preserved. • Emerging technologies improve the chemical stability and preservation of oils. • Extraction conditions must be operationally/economically optimized for each matrix. • Overall, use of harmful solvents can be avoided/reduced for oil greener extraction.