Multifunctional Valorisation of Pistachio (Pistacia spp.) By-Products: A Review of Sustainable Applications in Environmental and Industrial Contexts

The growth of pistachio (Pistacia spp.) production, particularly in America, Iran, and Turkey, has resulted in the production of substantial quantities of by-products, including shells, fruit husks, leaves, resins, and tree pruning waste. Although these fractions contain a range of beneficial secondary compounds, they are rarely used. Recent advances in nanotechnology and materials engineering suggest that they can be used as inexpensive, renewable raw materials in the fields of agriculture, the food industry, cosmetics, pharmaceuticals, and environmental engineering. Pistachio by-products have been shown to exhibit antioxidant, antibacterial, antifungal, and anticorrosive properties, making them good candidates for use in active packaging systems and nanoencapsulation. They may also be valuable as fertilisers, animal feed, and composite materials. They have been found to have potential roles in industrial pollutant removal and energy storage, and as ‘green’ precursors for nanomaterials. This review summarises the current knowledge on the multifunctional applications of Pistacia spp. by-products, emphasising their importance in implementing circular economic strategies and sustainable industrial development. This study also addresses the practical application of pistachio by-products, as well as the widely appreciated nuts, within the domain of patents, thereby illustrating the prospective pathway of currently emerging solutions in the context of sustainable development.