Determinação do teor de óleo em sementes individuais de amendoim pelo método de ressonância magnética nuclear: estudo de variância e relação com o método Soxhlet

Determination of oil content in individual peanut seeds by the nuclear magnetic resonance method: variance studies and relationship with the Soxhlet method

ARTIGOS

Determinação do teor de óleo em sementes individuais de amendoim pelo método de ressonância magnética nuclear: estudo de variância e relação com o método Soxhlet¹

Determination of oil content in individual peanut seeds by the nuclear magnetic resonance method – variance studies and relationship with the Soxhlet method

Ignácio José de GodoyI, ²; João Paulo Feijão TeixeiraII, ²; Violeta NagaiIII, ²; Carlos Rettori^IV

^ISeção de Genética, Instituto Agronômico de Campinas (IAC), Caixa Postal 28, 13001 Campinas

IISeção de Fitoquímica, IAC

IIISeção de Técnica Experimental e Cálculo, IAC

IVInstituto de Física, UNICAMP

RESUMO

Sementes individuais de amendoim colhidas aos 108, 115 e 120 dias foram utilizadas para um estudo de adequação da análise do teor de óleo pelo método de ressonância magnética nuclear (RMN). Foram feitas análises de correlação e regressão deste com o método extrativo, Soxhlet, mostrando os dados uma correlação positiva (r = 0,98) entre ambos. Embora os valores obtidos pelo Soxhlet tenham sido ligeiramente maiores, é possível estimar, através de uma equação de regressão linear, os teores de óleo em Soxhlet a partir dos teores em RMN. Foram feitas, ainda, estimativas de variabilidade entre plantas e entre sementes dentro de plantas e do número de plantas e de sementes por planta necessário para estimar a média de teores de óleo com erro-padrão da média igual a 0,5, 1 e 2%. As estimativas de variabilidade entre sementes individuais sugerem a necessidade de usar amostras compostas de grupamentos de sementes para que as médias populacionais do teor de óleo estejam contidas em intervalos de até y ± 2%.

Termos de indexação: amendoim, sementes, óleo, teor, ressonância magnética nuclear.

SUMMARY

Individual peanut seeds were studied concerning the feasibility of oil content evaluations by the Nuclear Magnetic Resonance method (NMR). Correlation and regression analyses with the extractive (Soxhlet) method were performed. A variance study among seeds per plant and seeds among plants was also made in order to access the possibility of selecting for oil content based on individual seed evaluations. The data showed a high and positive correlation (r = 0.98) between both methods. Although the values obtained by the Soxhlet method were slightly higher than those obtained by the NMR, the relationship between both methods was linear, indicating the possibility of correcting the data when necessary. The observed variances in oil content among seeds of the same plant were at least equal to those observed among plants. These values indicated that, for deviations in oil content of up to 2%, a number of seeds always higher than 1 is necessary for sampling.

Index terms: peanut seeds, oil content, nuclear magnetic resonance.

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Recebido para publicação em 27 de junho de 1985.

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1

Parcialmente financiado pelo Convênio IAC/FINEP.

2

Com bolsa de suplementação do CNPq.

Datas de Publicação

• Publicação nesta coleção
  11 Dez 2007
• Data do Fascículo
  1986

Histórico

• Recebido
  27 Jun 1985