Philippine E-Journals

Purification and Characterization of Antioxidant Proteins from Rice Bean (Vigna umbellata)

Sheryl Joyce B. Grijaldo | Marynold V. Purificacion | Paquito E. Relox | Mary Ann O. Torio

 

Abstract:

Higher intake of plant protein is associated with lower risk in degenerative diseases caused by oxidative stress, thereby places enormous demand in the identification of plant-based sources of protein like legumes. Rice bean (Vigna umbellata) is known to be a great source of low-cost and good nutritional quality protein for utilization in food products. This study characterized the proteins from rice beans reflecting their nutritional quality and potential as a food additive. The total soluble proteins of rice beans were extracted using 50 mM Tris-HCl (pH 7.2) and 35mM potassium phosphate buffer (pH 7.2) containing 0.40 M NaCl. Major storage protein was purified using ammonium sulfate fractionation, selective precipitation, and gel filtration chromatography. Pepsin digestion was done for 2 hours followed by multiple digestions of trypsin, chymotrypsin, thermolysin digests on the purified protein for 1 hour, 2 hours, and 4 hours, respectively. V. umbellata protein concentrate, hydrolysates (1 hr, 2 hrs, 4hrs), and dialysate were subjected to DPPH (2,2-diphenyl-1-picryl-hydrazyl-hydrate) assay to confirm antioxidant activity. V. umbellata crude protein extract and enzyme-digested protein extract provided (4-hr incubation) the highest antioxidant activity.