Antioxidant capacity of hydrolyzed protein fractions obtained from an under-explored seed protein: Gingerbread plum (Neocarya macrophylla)

The antioxidant capacity of gingerbread plum kernel protein fraction (albumin, globulin and glutelin) hydrolysates (GPKH) was studied. Gingerbread plum kernel protein fractions were hydrolyzed through a combined action of two digestive enzymes (pespsin and trypsin). The hydrolyzed fractions were subjected to antioxidant test via several chemical assays such as: DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging activity, hydroxyl radical-scavenging activity, reducing power and metal chelating activity. Total phenolic contents, amino acid composition and molecular weight distribution were also evaluated. The glutelin fraction hydrolysate showed the strongest antioxidative activity throughout the entire investigation: 79.09, 58.81, 52.08 % and 40.7 μg/mL GAE for DPPH, hydroxyl radical, chelating activity and total phenolics respectively. GPKH possess a molecular weight ranging from 300 to 4000 Da and also showed much more high reducing power than some common standards such as BHA and α-tocopherol indicating that, hydrolysates derived from gingerbread plum kernel protein could be a new antioxidants source.