Impact of cooking on the bioactive compounds and antioxidant activity of gherkin (Cucumis anguria L.)

Abstract

Despite the high consumption of Japanese gherkin in the Northeast of Brazil, very few studies with this vegetable are found in the literature. As it is consumed raw or after cooking, being mainly consumed cooked, there was the interest to know if cooking could influence bioactive compounds content and antioxidant activity since high temperatures are related to benefits losses in food. This research aimed to compare the content of bioactive compounds and the antioxidant activity between in natura and cooked Japanese gherkin. Gherkins were submitted to quantification of carotenoids, anthocyanins, vitamin C and phenolic compounds, in addition to the antioxidant activity analyses through the ferric reducing antioxidant power (FRAP) and the DPPH free radical scavenging methods. After cooking, carotenoids (from 4.90 to 4.59 ?g.g-1) and phenolic compounds (from 17.07 to 14.95 mg.100 g-1) content decreased, but with no significant difference between in natura and cooked samples. As for the antioxidant activity, the in natura gherkin showed a higher value (3.31 ?M Ferrous Sulfate.g-1) than the cooked one (1.96 ?M Ferrous Sulfate.g-1) for FRAP method, while for DPPH method no difference between the samples was detected. Anthocyanin and vitamin C were not detected in gherkins. We concluded that, in general, cooking did not affect the bioactive compounds of gherkins and that antioxidant activity increased.