Obtenção e avaliação de bixina a partir de extrato de urucum (Bixa orellana L.)

AUTOR(ES)
DATA DE PUBLICAÇÃO

1994

RESUMO

Purified dark red extract of bixin was obtained from crude extract of annatto (Bixa. orellana L.) This natural colorant was obtained by acid and alkaline precipitation of the crystals of bixin. The stability of the pigment was studied as a function of temperature (105°C) and as well ligth as critical moisture from the extracts. Crude extract of annatto was obtained with ethyl alcohol as solvent. Purified bixin was obtained by acid precipitation, after extraction of colorant with other solvents of different polarities, such as acetone and isopropyl alcohol. This methodology was compared with the acid and alkaline precipitation and cold crystallization of extract obtained from annatto seeds. The extraction yield of bixin on a dry weight basis, varied between 35.5 and 65.5%. Purification of extracts with 65.5% bixin in acetone and isopropyl alcohol at 35 °C, furnished bixin crystals of 94.7% purity, with an increase in purity being 1.5 fold. In extracts obtained from annatto seeds, using alkaline methods under ambient temperature, bixin with 73.4% purity was obtained. This was compared with an integrated method of extraction and purification that furnished 69.3% of bixin. The effects of temperature and ligth on the stability of the bixin was studied by measuring the loss of absorbance with time. From these data, the reaction rate and half life for bixin in each system were determined. Temperature was the most destructive agent, followed by light. Critical moisture was determined using sorption isotherms determined for the purified extract of bixin obtained from crude extract of annatto, and compared with water-miscible extract obtained by spray-drying, which showed the highest capacity of water absorption. These extracts were also used to prepare a drink employing a commercial formulation.

ASSUNTO(S)

carotenoides plantas - pigmentos corantes

ACESSO AO ARTIGO

Documentos Relacionados