Anthocyanidins in Babica, Ljutun and Crljenak Kaštelanski grapes and kinetic of their degradation under different storage conditions

Profiles of anthocyanidins (delphinidin, cyanidin, malvidin, pelargonidin and peonidin concentrations) of the skin extracts from autochthonous Croatian (Dalmatian) red grape varieties Babica, Ljutun and Crljenak Kastelanski were analysed using high-performance liquid chromatography. Identification and quantification of aglycones after acid hydrolysis of the anthocyanins was performed using anthocyanidin standards. In all extracts, malvidin was the major anthocyanidin (ranging from 0.2237 mg center dot l(-1) to 0.2738 mg center dot l(-1)), while the extracts of Ljutun and Crljenak Kastelanski also contained high amounts of delphinidin. Pelargonidin derivatives were detected in all samples and their concentration ranged from 0.0359 mg center dot l(-1) to 0.0371 mg center dot l(-1). The concentrations of total monomeric anthocyanins and their changes during 70 days of storage under different conditions (at room temperature exposed to the sunlight, at room temperature in the dark, and at + 4 degrees C protected from light) were measured by the pH-differential method. Degradation rates of total monomeric anthocyanins in all extracts exposed to light followed the first order reaction kinetics, and after 70 days there were no monomeric forms in them. The highest degree of anthocyanins stability was recorded for the samples that were kept at + 4 degrees C and protected from light, where only 5-8% of these compounds were degraded.