Submitted to: Institute of Food Technologists
Publication Type: Abstract Only
Publication Acceptance Date: 6/29/2008
Publication Date: 6/29/2008
Citation: Seifert, L.E., Davis, J.P., Sanders, T.H. 2008. Protein Hydrolysis of Defatted Peanut Meal to Improve Nutritional and Functional Properties.Institute of Food Technologists #007-09.
Technical Abstract: Technical Abstract: Defatted peanut meal is a commercially available, high protein (50-60%) material remaining after oil extraction from peanut seed. Technologies are needed to improve the economic value of this commodity. The objectives of this work were to evaluate antioxidant activity and functional properties of defatted peanut meal after hydrolysis with different commercial proteases. Dispersions (10% solids) were hydrolyzed at the optimal temperature and pH for each protease. Enzymes were heat inactivated at 90ºC/15 min before the dispersions were centrifuged and the soluble fractions (hydrolysates) were collected for subsequent testing. Degree of hydrolysis (DH) was determined spectrophotometrically by the trinitrobenzenesulfonic acid method. Protein solubility was measured using the BCA assay. Approximate protein molecular weights were determined by SDS-PAGE. Antioxidant activity was measured using the Oxygen Radical Absorption Capacity assay. Interfacial activity was evaluated via pendant drop tensiometry. DH for pepsin hydrolysates ranged from approximately 6 to 12% whereas Alcalase hydrolysates ranged from 20 to 35%. Increasing DH minimally affected protein solubility as compared to unhydrolyzed controls. Soluble protein content was approximately 20 and 25 mg/ml for Alcalase and pepsin hydrolysates, respectively. SDS-PAGE confirmed that all hydrolysates contained low molecular weight peptides ranging from 2.5-10 kDa. One band in the basic arachin region was most resistant to Alcalase hydrolysis and one band in the intermediate arachin region was most resistant to pepsin hydrolysis. Antioxidant activity of the Alcalase hydrolysates increased three-fold after hydrolysis. Surface activities of all hydrolysates were greater than unhydrolyzed controls, with pepsin hydrolysates being most surface active. These results suggest that peanut meal could be made more valuable via enzymatic hydrolysis to create low molecular weight peptides with improved nutritional value and increased surface activity. This research may also be applicable for improving the quality of other peanut based products such as peanut flours.