ACE-inhibitory and antioxidant properties of potato (Solanum tuberosum)

Proteins were isolated from potato tubers (Solanum tuberosum) at different physiological states, and by-products from the potato industry were used to evaluate their ACE-inhibitory and radical-scavenging potencies. Protein isolates and by-products were autolysed or hydrolysed by alcalase, neutrase and esperase. Hydrolysis increased the inhibition of the angiotensin-converting enzyme (ACE) and the radical-scavenging activity. The ACE-inhibitory potencies of the hydrolysates were high (IC50 = 0.018 - 0.086) and the by-product fractions showed ACE-inhibition also before hydrolysis. All samples exhibited low radical-scavenging activity, and hydrolysis for 2 h with proteases was needed to produce an increase in the activity. Ultrafiltration through 10-3 kDa membranes efficiently separated the ACE-inhibitory compounds into permeate fractions. The results of this study suggest that potato is a promising source for the production of bioactive compounds as ingredients for developing functional foods with a beneficial impact on cardiovascular health. (c) 2008 Elsevier Ltd. All rights reserved.