The obtainment and the characterization of the anthocyanidins vegetal from the grape peels

Abstract

The anthocyanidins are the red, violet and blue colorants that are found in the vegetal materials together with the flavones, flavonoids, tannins, etc. The anthocyanidins, d\besides the fact that they represent a source of natural colorants, have also been a subject of research due to their oenological, antibacterial and anti-neoplastic properties. This paper demonstrates the testing of two extracting methods: the discontinuous method with the variants with and without stirring and the Soxhlet continuous method. The efficiency of the extracting methods was considered taking into account the time of extraction and the concentration of anthocyanidins of the vegetal extracts. As vegetal raw materials there were used the grape peels of Vitis vinifera belonging to the varieties of Cabernet Sauvignon, Merlot, Babeasca neagra and Feteasca neagra The extracting process in the discontinuous system without stirring was proven to be the best for the achievement of the anthocyanidins vegetal extracts because they are performed at a temperature of only 30C and do not favor the processes of oxidation of the active substances due to the lack of stirring of the extracting system. Among the tested vegetal materials it was noticed the richest in anthocyanidins are the peels of the varieties Cabernet and Merlot through the no stirring discontinuous method, that is 2520,61 mg/L and 1703,63 mg/L. In the case of the extracting processes in continuos method that used the peels of grapes of the varieties Babeasca neagra, Merlot and Feteasca neagra, the concentrations of anthocyanidins of the obtained extracts were 63% smaller than in the case of the anthocyanidins extract from the peels of Babeasca neagra, with 38% smaller than in the peels of Merlot and with 45% than in the case of the extract from the peels of Feteasca neagra.