AJUSTE DE METODOLOGIA PARA EXTRAÇÃO DE PIGMENTOS EM FOLHAS DE REPOLHO E BRÓCOLIS

Abstract

The determination of chloroplastidic pigments is a technique that helps to identify the physiological conditions of plants. Solvents such as acetone, dimethylformamide, dimethylsufoxide (DMSO), methanol and chloroform have been used in the extraction of these pigments. DMSO has been used due to the ease of handling and storage of the samples for further evaluation of the pigments, however, the effectiveness of the extraction depends on the time and temperature of extraction and varies between species. This study was carried out to adjust the extraction of chloroplastinic pigments from cabbage leaves (Brassica oleracea L. var. Capitata) and broccoli leaves (Brassica oleracea L. var, italica) in DMSO solvent. The experiment was conducted in a completely randomized design with four replicates. The leaf samples (1 gram) of cabbage and broccoli were collected and then the material was placed in a test tube containing 5 mL of DMSO saturated with calcium carbonate and subjected to temperatures of 30 and 65°C by 12, 24, 36 and 48 hours. After the incubation period at each temperature, the samples were read in a spectrophotometer at the absorbances of 665, 649, 480, 415 and 435 nm for the determination of chlorophyll a, chlorophyll a, carotenoids, pheophytinization (IF). The results indicate that the extraction of pigments in cabbage leaves should be carried out at 30°C for 24 hours, based on the extraction of chlorophyll a. For broccoli when considering the lowest extraction of chlorophyll b, the leaf material should be incubated at 65°C for a period of 22 hours.