Prospects of Maize (Corn) Wet Milling By-Products as a Source of Functional Food Ingredients and Nutraceuticals

Maize (corn) consists of germ, endosperm and pericarp, with different chemical compositions. During wet milling, the maize is disintegrated into the main product starch and by-products, including maize germ, maize fibre and maize gluten (the technical term for maize/corn endosperm-specific proteins and not the same as wheat gluten). These by-products are used as low-value animal feed products. The maize germ contains high amounts of tocols and phospholipids, the maize gluten is rich in carotenoids and the maize fibre fraction is rich in phytosterols and complex carbohydrates. Each by-product has a potential to serve as a precursor in the manufacture of functional food ingredients or nutraceuticals that have antioxidant, anti-inflammatory, hypocholesterolaemic, hypolipidaemic and hypoglycaemic properties. These food ingredients/nutraceuticals can be obtained through physical, chemical or enzymatic processes. Some nutraceuticals and food ingredients with market potential include maize/corn fibre gum, oil, arabinoxylans and xylooligosaccharides from maize fibre; maize germ oil and phospholipid ester from maize germ; and carotenoids and oligopeptides from maize gluten. This review focuses on current and prospective research into the use of maize germ, maize fibre and maize gluten in the production of potentially high-quality food ingredients or nutraceuticals.