Termodinâmica de partição do corante natural carmim de cochonilha em diferentes sistemas aquosos bifásicos

• Autor(a) principal: Leite, Luciana de Oliveira Reis
• Data de Publicação: 2010
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/2095
• topic: Termodinâmica de partição; Corante natural carmim de Cochonilha; Sistemas aquosos bifásicos; Thermodynamic partition; Natural dye cochineal carmine; Aqueous two phase systems; CNPQ::CIENCIAS EXATAS E DA TERRA::QUIMICA::FISICO-QUIMICA

Nowadays, dyes and pigments are largely utilized in the industries foods, cosmetics and drugs. Because several synthetic colorants have been considered carcinogenic and toxic to health, the demand for natural dyes has increased. Within this context, the natural red pigment extracted of dried bodies of female insect Dactylopius Coccus Costa (cochineal) has received large attention. The major component of the pigment extracted from cochineal is carminic acid which represents approximately 20% of insect body mass. It is considered functional because not only to may be used as a food colorant but also it to protect food against the deterioration by oxidations. The extraction of carminic acid is commonly performed by use of complexation with aluminum and calcium in aqueous solution and the complex formed is known as carmine. The presence of impurities in this process directly influences the quality of the dye. For solve this problem, some works have searched to develop powerful methodologies for purification of carmine dye to satisfy the expectations and needs of industry and consumers. A powerful and correct ecologically alternative for the purification of solutes that has emerged in the last years is aqueous two-phase extraction. Aqueous two-phase systems (ATPS) are obtained when two water-soluble polymers or a polymer and a salt are dissolved in water beyond a critical concentration at which two immiscible phases are formed. In a recent work, Mageste et al. introduced ATPS as alternative for purification of carmine dye. These authors evaluated the partitioning behavior of carmine in different ATPS formed by mixture of aqueous solution of a polymer (or copolymer) and a salt. It was revealed that Carmine molecules concentrate in the polymer/copolymer-rich phase of such systems. This result has been attributed to enthalpic molecular interactions between carmine molecules and polymer/copolymer molecules. This work has the purpose of improve the knowledge of carmine partitioning behavior in aqueous two-phase systems to increase the efficiency of ATPS in the separation of this solute. For this, partition coefficient of carmine (K) was evaluated for several ATPS and thermodynamic parameters of transference of dye (ΔtrH, ΔtrS and ΔtrG) have been obtained.