Carotenoids in Cereal Food Crops: Composition and Retention throughout Grain Storage and Food Processing

Carotenoids are C40 isoprenoids synthesized by plants, as well as some bacteria, fungi and algae, that have been reported to be responsible for a number of benefits conferred on human health. The inability of animals and humans to synthesize de novo these compounds is the reason why they must be introduced from dietary sources. In cereal grains, carotenoids are important phytochemicals responsible for the characteristic yellow colour of the endosperm, which confers nutritional and aesthetic quality to cereal-based products. Cereals are staple foods for a large portion of the world population, and the biofortification of cereal grains with carotenoids may represent a simple way to prevent many human diseases and disorders. Unfortunately, evidence exists that the storage and processing of cereal grains into food products may negatively impact their carotenoid content; so, this loss should be taken into consideration when analysing the potential health benefits of the cereal-based products. Focusing on the recent updates, this review summarizes the chemical composition of the carotenoids in the grains of staple cereals, including wheat, maize, rice and sorghum, the main factors that affect their carotenoid content during storage and processing and the most fruitful strategies used improve the grain carotenoid content and limit the carotenoid post-harvest losses.