Chlorophyll stability in yerba maté leaves in controlled atmospheres
The objective of this research was to investigate the stability of chlorophyll in yerba maté leaves in controlled atmospheres of CO2/air mixtures and different water activities at 25°C.Two levels of water activity were selected corresponding to saturated salt solutions of LiCl (a w=0.113) and MgCl2(...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
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Instituto de Tecnologia do Paraná (Tecpar)
1999-01-01
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| Series: | Brazilian Archives of Biology and Technology |
| Subjects: | |
| Online Access: | http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89131999000100012 |
| Summary: | The objective of this research was to investigate the stability of chlorophyll in yerba maté leaves in controlled atmospheres of CO2/air mixtures and different water activities at 25°C.Two levels of water activity were selected corresponding to saturated salt solutions of LiCl (a w=0.113) and MgCl2(a w=0.330) and three levels of CO2/air mixtures (0/100,20/80 and 40/60). The chlorophyll content was evaluated using a liquid chromatography HPLC technique. Experimental values varied between 2.16 and 0.61 mg/g of dry matter. For each sample, 5 determination were made during 58 days. Experimental values were fitted to an equation describing a first order reaction. In all cases, the agreement was good with P<3 10-3. The initial concentration of chlorophyll dropped, in average, to 30.5% after 58 days. However, after comparing the velocity constants, no differences were found between them.<br>O objetivo deste trabalho foi pesquisar a estabilidade da clorofila em folhas de erva mate em misturas atmosféricas controladas de CO2/ar e diferentes atividades de vapor de água a 25ºC. Dois níveis de atividade de vapor de água foram selecionadas, correspondendo a soluçoes saturadas de LiCl (a w=0.113) e MgCl2 (a w=0.330) e três níveis de misturas CO2/ar (0/100,20/80 e 40/60). O conteúdo de clorofila foi avaliado usando a técnica de cromatografia líqüida HPLC. Os valores experimentais variaram entre 2.16 e 0.61 mg/g de matéria seca. Para cada amostra foram realizadas 5 determinaçoes durante 58 dias. Os valores experimentais foram ajustados para uma eqüação descrevendo uma reação de primeiro ordem. Em todos os casos houve boa concordância P < 3 10-3. A concentração inicial de clorofila ficou reduzida em média um 30.5% depois de 58 dias. Porém, depois da comparação das constantes de velocidade, não foram achadas diferenças entre elas. |
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| ISSN: | 1516-8913 1678-4324 |