Nanodelivery systems for d-limonene; techniques and applications

• d -limonene (DL) as the major volatile of citrus essential oils is widely used in food flavorings. • Many therapeutic properties and health benefits has been attributed to DL. • DL is chemically unstable in the presence of air, light, moisture, and high temperatures. • Different lipid-based and biopolymeric systems have been developed for encapsulating DL. • Using nanocarriers have led to improvement of its bioavailability and longevity. The d -limonene (DL), a bioactive ingredient in citrus peels, is a monoterpene, volatile, and aromatic flavor which has antioxidant, anti-inflammatory, and anti-cancer properties and many health-promoting effects. To protect DL against the harsh conditions during the processing and storage, its entrapment in biocompatible, biodegradable and safe nanodelivery systems can be used. This review highlights recent studies on nanocarries used as delivery systems for DL including polymeric nanoparticles, micelles, nanoliposomes, solid lipid nanoparticles, nanostructured lipid carriers, nanosuspensions, and nanoemulsions for DL. Furthermore this review refers to updated information regarding DL bioavailability, release rates as well as applications in functional food products. Safety issues and health risks regarding the consumption of these products also was discussed which opens new horizons in food technology and nutrition with possibilities of commercialization in the near future. Overall, DL encapsulated within nanocarriers are considered safe, meanwhile more studies should be performed regarding the safety issues of nanodelivery of DL. In near future, it is assumed that nanoencapsulated DL will be broadly applied in the food and beverage products, cosmetic, pharmaceutical and perfume industries.