A novel multi-biofunctional protein from brown rice hydrolysed by endo/endo-exoproteases

Abstract

Brown rice, which is a less allergenic food grain and contains essential amino acids, was hydrolysed by bromelain and PROTEASE FP51® to improve its functionalities and taste for food applications. The hydrolysate prepared by bromelain (eb-RPH) had high protein solubility, surface hydrophobicity, low molecular weight peptides, hydrophobic amino acids (leucine, valine and glycine) and flavor amino acids (glutamic acid and aspartic acid). The eb-RPH exhibited higher 1,1-diphenyl-2-picrylhydrazyl (DPPH˙) and 2,2′-azino-bis 3-ethylbenzthiazoline-6-sulfonic (ABTS˙⁺) radical-scavenging activities of 76.62% and 52.96%, respectively, and possessed a better foaming capacity (221.76%) and emulsifying capacity (32.34%) than the hydrolysate prepared by PROTEASE FP51® (ep-RPH) did. The eb-RPH gave the desired taste, which is attributed to volatile flavor compounds (benzaldehyde, benzeneacetaldehyde and 2-acetyl-1-pyrroline) and non-volatile flavor compounds, such as monosodium glutamate, 5′-guanosine monophosphate and 5′-inosine monophosphate (0.07, 0.03 and 0.05 mg mL⁻¹, respectively). Brown rice peptides generated by bromelain were novel bioactive peptides with multifunctional properties.