Funkcionalna hrana je hrana koja ima povoljan uticaj na ljudsko zdravlje mimo uobičajenih nutritivnih funkcija. Biološki aktivna jedinjenja su nosioci povoljnog dejstva funkcionalne hrane. Brojni naučni dokazi govore u prilog tome da je ishrana bogata pojedinim namirnicama (kao što su to na primer voće i povrće) direktno u vezi sa smanjenim rizikom od hroničnih, nezaraznih bolesti, tako da se na tim saznanjima razvio koncept funkcionalne hrane. Otkrivaju se funkcionalne osobine tradicionalnih namirnica, ali se dizajniraju i nove funkcionalne namirnice. Uobičajene izjave koje prate tu vrstu namirnica mogu se svrstati u dve kategorije: (1) izjave o odnosu strukture i funkcije (engl. Structure and function claims) moraju da budu istinite i da ne dovode u zabludu potrošača. Te izjave ne moraju da budu odobrene od strane FDA; (2) zdravstvene izjave (engl. Health claims ili disease-specific claims) moraju da budu autorizovane od strane FDA i da poseduju značajnu naučnu potvrdu (Hillovi kriterijumi). Neophodno je rangiranje dokaza različitih tipova studija koje podržavaju zdravstvenu izjavu. Veliki broj biološki aktivnih jedinjenja su nestabilna tokom tretmana i čuvanja. Ona podležu mnogobrojnim hemijskim reakcijama, kao što su to oksidacija, hidroliza, termička degradacija i Maillardova reakcija, što rezultira smanjenjem bioiskoristljivosti. Povoljan efekat biološki aktivnih jedinjenja direktno zavisi od primenjenog tretmana. Functional foods are foods that may provide a health benefit beyond basic nutrition. Numerous scientifically proven pieces of evidence in many epidemiological studies indicate that nutrition abundant in certain foods (e.g. fruits and vegetables) is directly correlated with a decreased risk of degenerative diseases. Biologically active compounds in functional foods may impart health benefits or desirable physiological effects. Functional attributes of many traditional foods are being discovered, while new food products are being developed with beneficial components. These results are closely related to nutrition's potentials in preventing chronic diseases. Based on these facts the concept of functional foods has been developed. Rigorous scientific investigation has to confirm the positive physiological effects of these compounds upon health. Labeling claims that are used on functional foods are of two types: (1) structure and function claims, which describe effects on normal functioning of the body, but not claims that the food can treat, diagnose, prevent, or cure a disease (claims such as >promotes regularity<, >helps maintain cardiovascular health<, and >supports the immune system< fit into this category); and (2) disease-risk reduction claims, which imply a relationship between dietary components and a disease or health condition. Structure and function claims do not require preapproval by the FDA, and they require much less stringent scientific consensus than disease-risk reduction claims. Many biologically active compounds are unstable during treatments and storage. They undergo many common chemical reactions such as oxidation, hydrolysis, thermal degradation and Maillard reaction, contributing to the lowering of bioavailability. Anyhow, beneficial effect of bioactive compounds depends directly on the applied treatment in the production of foods.