Phytonutrients From Edible Oil Refining Waste-Streams: Recent Advances in Recovery and Valorization Approaches...

The edible oil refining process is critical for improving oil quality and extending its shelf-life. By-products from refining, including gums, soapstock, spent bleaching earth (SBE), and deodorizer distillate (DD), are generated in large volumes and often discarded despite being rich in valuable phytonutrients such as tocopherols, phytosterols, and polyphenols. Valorization is a sustainable approach to address these by-products in response to the increasing demand for adapting sustainable practices in the food industry. This review focuses on the by-products resulting from the refining of the top three oilseeds, soybean, rapeseed/canola, and sunflower and examines their potential for sustainable valorization. To that end, available literature relating to the effects of chemical and physical refining processes on phytonutrient content is explored, with an emphasis on the losses of individual phytonutrients that occur during refining stages. Main strategies used for recovering these compounds from refining by-products, particularly DD, are discussed. Beyond recovery, the potential of biotechnological approaches for producing other valuable compounds, such as enzymes, is highlighted. Furthermore, the integration of phytonutrient recovery with microbial bioprocesses, such as fermentation, is suggested for refining by-products, such as DD, to address the remaining oily waste after phytonutrient recovery and achieve "zero-waste" concept. This approach can provide an opportunity to minimize waste, reduce environmental impacts, and align valorization with the principles of a circular economy. By exploiting all ingredients in by-products, this approach can maximize value addition and generate new economic opportunities.