Estudos sobre crescimento e conteudo de esteviosideo, açucares soluveis totais e proteina de folhas de Stevia rebaudiana Bert. em dois fotoperiodos

AUTOR(ES)
DATA DE PUBLICAÇÃO

1979

RESUMO

Stevia rebaudiana Bert. contains a tetracyclic diterpene glycoside, stevioside, which is three hundred times sweeter than sucrose. As such this compound is of potential economic interest. Stevioside from plant extracts may be rapidly isolated and quantified through bi-dimensional thin layer chromatography.Isolated samples may be eluted in water, with insignificant losses and then assayed colorimetrically by the anthrone method against stevioside or glucose standarts. The solvents employed for chromatography are butanol:ethyl acetate:isopropanol:water(35:100: 60:30) in the first dimension and ethyl acetate:acetic acid:water(8:4:1) in the second. In this system stevioside is located at Rf 0,56 and 0,12 in the first and second dimensions respectively. When assaying stevioside, glucose may be employed as a standard due to the optical densitities of equal quantities of these substances bearing a constant ratio reiated to their molecular weights. Two phases are distinguishable during leaf growth:firstly,a rapid expansion phase in which dry weight remains constant and growth is due mainly to the entry of water, followed by the second phase(beyond leaf areas of 10 cm2) in which dry matter and protein contents increase due to concomitant carbon fixation in the leaf. The absolute and relative levels of proteins and sugars show different patterns of development during ontogeny reflecting their divergent functions in young leaf tissue. ... Note: The complete abstract is available with the full electronic digital thesis or dissertations

ASSUNTO(S)

açucar plantas açucareiras - cultivo stevia rebaudiana

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