Upcycling commercial nut byproducts for food, nutraceutical, and pharmaceutical applications: A comprehensive review

This article presents a comprehensive overview of upcycling commercial nut byproducts (such as Brazil nut, cashew, hazelnut, macadamia, peanut (also known as a legume), pecan, pine nut, pistachio, and walnut) for food, nutraceutical, and pharmaceutical applications. Upcycling nut byproducts, namely husk/hull, hard shell, brown skin, defatted flour/meal/cake, pine cone, cashew nut shell liquid, cashew apple, walnut septum, and dreg/okara, has great potential, not only to reduce/minimise waste, but also to fit within the circular economy concept. Each byproduct has its own unique functional properties, which can bring significant value. These byproducts can be used as value-added ingredients to promote better health and well-being, due to their rich sources of diverse bioactive components/phytochemicals, polysaccharides, fibre, lignin, prebiotics, oils, proteins, bioactive peptides, minerals, and vitamins, among other components. This comprehensive review provides a basis for future research and development of product applications for nut byproducts. More studies are needed on novel product development to valorise nut byproducts.