Application Orange Pomace as Low-Cost Biosorbent in Removing Heavy Metals from Brown Oryza Sativa Rice

Rice, beyond being a staple carbohydrate source, is a treasure trove of valuable nutrients and bioactive compounds with significant health benefits. It contains essential nutrients like dietary fiber, minerals, protein, and B vitamins, along with potent phytochemicals such as tocols (tocopherols and tocotrienols), oryzanol, phenolic acids, and flavonoids. These compounds contribute to rice's antioxidant, anti-inflammatory, anticancer, and hypoglycemic properties, making it a potential functional food and nutraceutical. Brown rice can contain higher levels of certain heavy metals, compared to white rice. The reason brown rice tends to have higher heavy metal levels than white rice is because the bran layer, which is removed during processing to make white rice, where these metals accumulates in the rice grain . Biosorption is indeed a method used to remove heavy metals from consumable rice, where the metals bind to the surface of insoluble compounds (biosorbents) within the rice. These biosorbents can be derived from various sources like agricultural waste, microorganisms, or algae. The process involves heavy metals being adsorbed onto the pores and surfaces of these materials, effectively removing them from the rice. The study explored the potential of orange pomace, a waste product from orange processing, to remove lead and cadmium from Tarom-Hashemi brown rice. The study findings indicate that orange pomace, particularly due to its pectin content, exhibits a significant capacity to adsorb lead (Pb) and cadmium (Cd) from aqueous solutions and potentially detoxify Tarom brown rice. This achievement is supported by the fact that the adsorption of these heavy metals is statistically significant ( p < 0.003) and the process is likely driven by the pectin's chemical properties. Using readily available agricultural and food industry waste, specifically pomaces, is a promising and cost-effective method for detoxifying high-consumption rice in Iran.