A full utilization of rice husk to evaluate phytochemical bioactivities and prepare cellulose nanocrystals

Rice husks (RHs) as an agro-waste generated from rice production, while its application is limited. This study was designed to introduce a full utilization of rice husks, which extracted the phytochemical at first and then produced cellulose nanocrystals (CNCs) as the use of the residue. Furthermore, the phytochemicals extracted from rice husk was identified and its biological activity, including antioxidant activity, cellular antioxidant activity (CAA) and antiproliferative activity, had been detected as well. Results showed the bound fraction of rice husk had higher antioxidant than common fruit and grain. Free fraction of rice husk deserved to have further analysis in antiproliferative activity due to its low cytotoxicity. The CNCs produced by residue was using delignification process and acid hydrolysis treatments. The chemical composition of the residue obtained after phytochemical extraction was determined. CNCs morphological investigation was performed using an optical microscope and atomic force microscopy (AFM). Our strategy is to achieve a comprehensive utilization of rice husks with both economy and environment benefits.