Nutritional characterization and effect of cooking on phenolic compounds, antioxidant capacity and sensory acceptability of commercial wild rice (Zizania aquatica L.)

Wild rice shows a relevance in the gastronomic area due to its nutritional value, nutty flavor, long grain appearance, dark color, and texture described by the firm outer layer and soft inside of the grain. Wild rice is rich in proteins and phytochemicals associated with health-promoting effects and can be used as cooked rice or ingredient in food products. Rice preparation involves hydrothernic treatment that affects its composition as observed in the traditional rice (Oryza sativa). However, the effect of cooking on phytochemicals and antioxidants properties has not yet been explored in wild rice. The present work reports a nutritional characterization of two commercial brands of wild rice grains (Zizania aquatica L.) from three different harvesting years, and the effect of cooking process on phenolic compounds, antioxidant properties and sensory acceptability. Raw wild rice showed contents of proteins from 12.4 to 13.3 g/100g and lipids from 0.79 to 1.10 g/100g, values which were at least 30% higher and 60% lower, respectively, than those reported to common white rice. The levels of oleate, linoleate and linoleate were 0.66–0.81%, contributing with at least 70% of unsaturated fatty acids. The contents of phenolics (flavonoids, proanthocyanins and anthocyanins) and antioxidant capacity were higher than those reported in traditional rice (Oryza sativa), and their levels remained about 74 and 58%, respectively, even after cooking. Sensory evaluation of raw and cooked wild rice point out that color and taste were the attributes best evaluated, showing a 87% of acceptability.