Assessing Mineral Profile Changes in White, Brown Rice and Byproducts under Different Agronomic Strategies

Background: In 2022 in Italy, the total production of rough rice was 1,200,000 tons, with the value of milled rice amounting to approximately 750,000 tons. High-quality rice is a priority for the rice sector in Italy, considering all the agronomic variables (rice varie- ties, agricultural management techniques, geographical area of cultivation and rice pro- cessing). Along with the commercial product, the major by-products obtained from rice cultivation and processing are husk and bran, 20% and 10% of the total weight of whole rice, respectively. Methods: The objectives of the present study were (i) to investigate whether agro- nomic practices influence the accumulation of essential and toxic elements in white (WR) and brown rice (BR) and byproducts (husk and bran) (ii) to understand and enhance the value of by-products through their mineral profile and antioxidant properties. Macro, mi- cro, toxic elements and total phenolic and flavonoid content in WR, BR and byproducts were analyzed to test correlations between grain quality traits with varieties, irrigation regime and location. Results: Arsenic (As) and cadmium (Cd) in WR varied with water management; Cd and nickel (Ni) increased along with soil Eh (wetting and drying management) with a greater impact on Ni concentration compared to Cd. Conversely, As content in WR were higher with continuous flooding. Rice variety also affected nutrient concentration (in par- ticular, Fe, Mn, and Zn) in grains. In BR, element concentrations can increase by up to six times compared to WR. The same trend was observed when comparing BR with byprod- ucts, with few exceptions (eg., Cd). In the last ones the elemental hierarchy was P ≥ K > Mg > Ca > Fe and Na with the greatest amounts of antioxidants. Conclusions: This study allowed to determine the relationships between agronomic choices and elemental composition of products and byproducts, allowing the improve- ment of product safety and nutritional value while addressing byproducts potential for food and farming uses.