Unlocking hidden potential of rice bran: Enzymatic treatment for enhancing techno-functional properties

Abstract

Rice bran (RB) is a by-product with limited application due to technological constraints. Enhancing its technological functionality as potential food ingredient will improve the sustainability of rice production. The aim was to study the impact of enzymatic and thermal treatments on defatted rice bran using six distinct commercial enzymes (carbohydrases and proteases) and dry heating by evaluating its technological, nutritional and functional properties. Enzymatic treatment increased up to 208% the soluble dietary fiber content (8.19 g/100 g) of defatted RB. Moreover, the solvent retention capacity, including water, oil, sodium carbonate, and sucrose, exhibited a noteworthy increase across all treatments (p < 0.05). Bran color changed after treatments, increasing its luminosity (L*) and decreasing the value of a* in all cases, but b* decreased when treated with protein-acting enzymes while increased with carbohydrate-acting enzymes. Proteases played a pivotal role in reducing particle size and forming gels requiring minimal force for application. Microscopic analysis revealed that carbohydrases-treated samples exhibited prominent cell wall breakage, while protease-treated ones showed a gel-like surface with less distinct protein bodies and layered walls. These comprehensive study sheds new transformations brought about by these enzymatic interventions, offering valuable insights into the optimization of rice bran functionality.