Production of copper-chelating peptides after hydrolysis of sunflower proteins with pepsin and pancreatin

Sunflower protein hydrolysates obtained with pepsin and pancreatin were used for purification of copper-chelating peptides by affinity chromatography with copper immobilized on solid supports. The chelating activity of purified peptides was indirectly measured by the inhibition of P-carotene oxidation in the presence of copper. The protein hydrolysate obtained after 180 min incubation with pepsin plus 60 min with pancreatin was the most inhibitory of P-carotene oxidation. Purified chelating peptides were 2.5 times more antioxidant than the parent protein hydrolysate. Chelating peptides were enriched in certain amino acids, such as histidine and arginine, with respect to the original hydrolysate. This work shows that chelating peptides may be generated during digestion of sunflower proteins and have a protective role, due to their antioxidative activity, and favour mineral bioavailability. (C) 2007 Swiss Society of Food Science and Technology. Published by Elsevier Ltd. All rights reserved.