Exploring the functional food potential of wild rice (Zizania palustris): A comparative analysis of morphological, nutritional, bioactive compounds, and antioxidant activity in whole, milled, and bran fractions

This study compared morphological, nutritional, and functional properties of wild rice ( Zizania palustris , ZP) fractions (whole, milled grain, bran) with white (WR) and brown rice (BR). Morphological properties were investigated by SEM, nutritional composition, amino acid and mineral profiles, antioxidant activities were analyzed using proximate analysis and microplate reader-based colorimetric assays. ZP exhibited elongated kernels with dense endosperm and horseshoe-shaped morphology, with significantly higher protein, dietary fiber, and essential minerals than WR and BR in all fractions, especially bran. ZP bran showed 2–11 fold higher phenolics and flavonoids, and 2–7 fold higher antioxidant activity than rice controls. ZP presented a nutritionally balanced amino acid profile, with higher lysine and essential to total amino acid ratio (~37%) approaching FAO/WHO recommendations, and unsaturated fatty acids (>87%), including long-chain polyunsaturated fatty acids rarely reported in common cereals. These findings highlight wild rice as a functional food ingredient with enhanced nutritional and antioxidant profiles. • Wild rice (ZP) has dense endosperm，thick brown bran and a horseshoe-shaped kernel. • ZP has higher protein, dietary fiber, minerals, and lower starch than white and brown rice. • ZP has a balanced amino acid profile with 2.3-fold higher lysine than rice controls. • ZP containes over 86% of unsaturated fatty acids, including rare long-chain PUFAs. • ZP has 2–11 fold higher phenolics/flavonoids and antioxidant activities, even after milling.