Nanotechnological Manipulation of Nutraceuticals and Phytochemicals for Healthy Purposes: Established Advantages vs. Still Undefined Risks

Numerous foods, plants, and their bioactive constituents (BACs), named nutraceuticals and phy-tochemicals by experts, have shown many beneficial effects including antifungal, antiviral, an-ti-inflammatory, antibacterial, antiulcer, anti-cholesterol, hypoglycemic, immunomodulatory and antioxidant activities. Producers, consumers, and the market of food- and plant-related compounds are increasingly attracted by health-promoting foods and plants, thus requiring a wider and more fruitful exploitation of the healthy properties of their BACs. The demand for new BACs, and for the development of novel functional foods, and BACs-based food additives is pressing from various sectors. Unfortunately, low stability, poor water solubility, opsonization, and fast metabolism in vivo hinder the effective exploitation of the potential of BACs. To overcome these issues, researchers have engineered nanomaterials, obtaining food-grade delivery systems, and edible food- and plants-related nanoparticles (NPs) acting as color, flavor, preservative ad-ditives, and natural therapeutics. Here, we have reviewed the nanotechnological transformations of several BACs implemented to increase their bioavailability, mask any unpleasant taste and flavors, or to be included as active ingredients in food or food packaging, to improve food ap-pearance, quality, and resistance to deterioration due to storage. The pending issue regarding the possible toxic effect of NPs, whose knowledge is still limited, has also been discussed.