The prolamins, from structure, property, to the function in encapsulation and delivery of bioactive compounds

Prolamins are plant-derived proteins that can be soluble in alcohol. Depending on their source, prolamins can be categorized as zein, gliadin, kafirin, hordein, secalin, and avenin. Due to specific structures and physicochemical properties, prolamins have been combined with bioactive compounds for encapsulation so that the bioactive substances restricted in some aspects can be better used in the field of food science and nutrition. This paper mainly summarizes the structural characteristics of zein, gliadin, kafirin, hordein, secalin, and avenin, reviews their properties, and overviews their extraction methods and applications of prolamins as nanocarriers to deliver bioactive compounds. Moreover, several strategies, such as surface coating, hollow nanoparticles, co-encapsulation, deamidation, and glycosylation, are emphasized to improve the stability and bioavailability of prolamins. In addition, the limitations and challenges of prolamins in the application of food science are focused on. Possible approaches to resolve the limitations of applying prolamins, such as low extraction rate of prolamins, low encapsulation and load rate of bioactive compounds, and instability of nanoparticles, are recommended. Finally, future outlooks of prolamins as nanocarriers for bioactive compounds in food applications are elucidated.