Maize bioactive peptides: From structure to human health

Maize represents a foundation of nutrition for nearly 4.5 billion people worldwide. The by-products of processing this cereal have been used as fodder and for the development of new products, such as bioplastics and biofuels, and have been proposed as a source of bioactive peptides. Diverse biological effects have been associated with these peptides including anti-oxidant, anti-inflammatory, anti-hypertensive, hepatoprotective, alcohol-metabolism-facilitating, anti-cancer, anti-microbial and dipeptidyl peptidase IV-inhibition, as well as cell-penetrating activities. Most of these have been described in in vitro studies. Currently, there are no reliable data supporting efficacy in humans and no health claims have been confirmed by food regulatory authorities. To further evaluate these compounds, several hurdles must be overcome including peptide purity, action specificity and bioavailability (absorption, distribution and metabolism) of intact peptides. In this manuscript, we summarise strategies for the obtention, identification and characterisation of maize-derived bioactive peptides. Furthermore, we discuss the health benefits attributed to these peptides and the role of food processing in exploiting their benefits as nutraceutical or pharmaceutical molecules.