Defatting and Defatted Peanuts: A Critical Review on Methods of Oil Extraction and Consideration of Solid Matrix as a By-Product or Intended Target

Peanuts, being crucial crops of global importance, have gained widespread recognition for their versatility and nutritional value. In addition to direct consumption, either with or without treatment, peanuts can be the subject of diverse applications focusing mainly on two distinct objectives: oil extraction and defatting processes. As a result of the first process, a solid matrix is generated as a by-product, necessitating the exploration of strategies for its valorization, while the second process is centered on obtaining protein-rich, low-fat peanuts, for which the oil recovered becomes the by-product. As consumers increasingly seek out plant-based foods for their potential health benefits, this trend is expected to persist, encompassing peanut-based foods as well. This review elucidates the methods used for extracting peanut oil, including mechanical and chemical processes that have been combined with biological or physical pre-treatment techniques. Their primary goals are to maximize oil extraction and unlock the untapped potential of defatted whole peanuts. Additionally, the review addresses the challenges and opportunities in both oil extraction and defatting processes, emphasizing the importance of sustainable practices and efficient resource utilization. The advantages and disadvantages of each method were also evaluated and critically analyzed. Developing novel methods for potential industrial applications and limiting the drawbacks associated with traditional methods became necessary. A comparison in terms of productivity, efficacy, specificity, quality of the extracts, and operating conditions was conducted, which favored the novel methods as being mostly environmentally friendly and cost-efficient.