Nutritional and nutraceutical changes in blue corn (<i>Zea mays</i>) stored at different temperatures

Recently, blue/purple maize has gained prominence for its beneficial health properties, however, in Mexico, post-harvest handling of pigmented corn grains reaches losses of up to 80%, where in addition to quantity, nutritional and nutraceutical quality is seriously affected by inadequate storage conditions. The objective of this research was to quantify the nutritional and nutraceutical changes in blue corn grains stored for four months at 6, 25, and 35 °C. The results indicate that, at the fourth month of storage, temperatures affected the nutritional content to a different extent, with decreases of 66.83% in moisture and 57.79% in protein, and with increases of 10.92% in carbohydrates and 49.67% in starch. The concentration of phenols, flavonoids and total anthocyanins decreased by 49.33, 61.09 and 53.33%, after four months of storage at 35 °C, which were reflected in reductions in antioxidant capacity by 17.87, 17.84 and 18.93% for 2, 2− diphenyl − 1−picrylhydrazyl (DPPH), 2,2-azino-bis (3−ethylbenzothiazoline −6−sulfonic acid) (ABTS) and ferric reducing antioxidant power (FRAP), respectively. However, no significant changes in the nutraceutical content were generated during the storage of the grains at 6 °C. High temperatures over a prolonged storage period could seriously affect the concentrations of functional compounds in blue/purple corn kernels before consumption.