Vitamina C em frutos de interesse tecnológico (IV. Comunicação sobre vitamina C)
Palavras-chave:
ácido ascórbico, vitamina c, teor total, método rotineiro, substâncias interferentesResumo
By means of adaptation for routine work we analised total vitamin C contents (reduced ascorbic acid plus dehydroascorbic acid)
by condensation of its oxydized form with 2,4 dinitrophenylhydrazin (DNP). The color developed by the condensation product was strongly influenced by the sulfuric acid concentration whenused to solubilize the DNP-derivate. The best value we found lies within the densities 1.800 and 1. 830.
There was no interference of glucose, frutose andgalacturonic acid within the concentration range usually observed in fruits. The total vitamin C contents os fruits of some technologically interesting species were significantly higher than those of reduced ascorbic acid.
The contents of this vitamin varied considerably within species, as expected. The same is true for variations according to the ripening stage and to the parts of the fruit; in citrus the latters could be arranged in decreasing order as follows: pee, flesh, juice and kernels.
Referências
BRUNE, W., BATISTA, C.M., SILVA, D.O., FORTES, J.M. & PINHEIRO, R.V. Sobre o teor de vitamina C em Mirtáceas. Rev. Ceres, Viçosa, 13(74):123-133. 1966.
BRUNE, W., SILVA, D.O. & MATTOS, J. Sobre o teor de vitamina C em Mirtáceas II. Rev. Ceres, Viçosa, 13(75):182-193. 1966.
HAWK, P.B., OSER, B.L. & SUMMERSON, W.H. Practical Physiological Chemistry. 132 ed., New York, McGraw Hill Book. 1954. 1440 p.
KOLLER, S. Graphische Tafeln zur Beurteilung Statistischer Zahlen, 28 ed., Varlag von T. Steinkopff. Dresden. 1943. 75 p.
ROE, J. H. Comparative analyses for Ascorbic Acid bythe2,4 Dinitrophenylhydrazin method the coupling reaction at different temperatures: a procedure for determining specificity, J. Biol. Chem., Baltimore, 236(5):1611-1613. 1961.
ROE, J.H. & KUETHER, C. A. A color reaction for Dehydroascorbic acid useful in determination of vitamin C. Science. New York, 95(2453):77. 1942.
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