Antioxidative and ACE inhibitory activities in enzymatic hydrolysates of the cotton leafworm, Spodoptera littoralis

The larvae of the cotton leafworm, Spodoptera littoralis, were used as a source of food proteins exerting possible biological activities. A simulated gastrointestinal digestion (IC(50) = 320 mu g/ml) and digestion by mucosal enzymes (IC(50) = 211 mu g/ml) reveals a significantly higher in vitro ACE inhibitory activity compared to hydrolysis using thermolysin (IC(50) = 1392 mu g/ml) and alcalase (IC(50) = 827 mu g/ml) as pretreatment. This indicates that the choice of enzymes to generate ACE inhibitory peptides is important. All hydrolysates were also tested for antioxidant activity using two tests: a radical scavenging test using DPPH and the ferric reducing antioxidant power (FRAP) assay, and they showed a similar antioxidant activity which was relatively low compared to the standard antioxidants BHT and vitamin C. As a conclusion, the data obtained suggest that insect protein can be used to generate hydrolysates, exerting both ACE inhibitory and antioxidant activity, which might be incorporated as multifunctional ingredient into functional foods. (C) 2008 Elsevier Ltd. All rights reserved.