Background: This study was performed to test the effects of pre-treating cherry tomatoes with a solution containing citric acid-NaCl-CaCl2 (10:10:24 g L(-1)), followed by one of three different drying regimes (40, 60, 80 °C) on the antioxidant capacity of their aqueous extracts and the extent of phenolic compound degradation.
Results: Chlorogenic acids, caffeic acid, ferulic acid, rutin and naringenin were all detected in the aqueous extracts. In fresh cherry tomatoes the predominant phenolic compound was rutin, followed by naringenin, which corresponded to 79% and 8% of the total phenolic compounds present, respectively. Pre-treatment was protective towards naringenin and had a modest protective effect on rutin and ferulic acid (0.1 > P > 0.05). Total phenolic content was similar in all samples, but there was a trend for the level of free polyphenols to be lower in treated tomatoes. The destruction of naringenin was confirmed by liquid chromatographic-mass spectrometric data.
Conclusion: A significant effect of temperature on the antioxidant capacity was observed. After this treatment the industry might introduce some advances in the processing of tomatoes, preserving the main nutritive characteristics and saving the products as semi-dried.
Keywords: antioxidant capacity; flavonoids; polyphenols; semi-drying; tomato.
© 2015 Society of Chemical Industry.