Turmeric (Curcuma longa l) oleoresin extraction with supercritical CO2

Turmeric (Curcuma longa L) is one of the most used source of natural color in the food industry. Curcuminoids can be obtained from the roots of this plant. These pigments impact a yellow color and they might be able to substitute synthetic dyes. Turmeric oleoresin extraction experiments have been carried out with supercritical CO2 to investigate the influences of the pretreatment of the rhizomes on oleoresin. The extractions were conducted at the Department of Chemical Engineering of the Federal University of Pará (Universidade Federal do Pará). Turmeric was dried at 70ºC and 105ºC. Extractions have been carried out at pressures of 200, 250 and 300 bar and a temperature of 45ºC. Results shown the total yield and the content of curcumin present in the oleoresin. Amount of oleoresin extracted from the material dried at 70ºC was larger while most of the curcuminoids remained in the solid material.Dentre as fontes de corantes naturais mais utilizadas na indústria de alimentos, encontra-se a cúrcuma (Curcuma longa L.) uma rizomaina do qual podem ser obtidas substâncias como a curcumina, demetoxicurcumina e bis-demetoxicurcumina. Estes pigmentos possuem coloração amarela e capacidade de substituir corantes artificiais. Com a finalidade de verificar a influência do pré-tratamento de secagem na extração, foram realizados experimentos de extração de oleoresina de cúrcuma com CO2 supercrítico, na unidade de extração do Laboratório de Engenharia Química da Universidade Federal do Pará, submetendo-se a matéria-prima a uma secagem nas temperaturas de 70 e 105oC. As extrações foram feitas a pressões de 200, 250 e 300 bar, e na temperatura de 45oC. Os resultados estão apresentados em tabelas e gráficos, em termos de rendimentos totais e teor de curcumina presente na oleoresina. A secagem a 70oC favoreceu a extração de oleoresina em termos de tempo de extração, e contribuiu para a manutenção de curcumina na matéria-prima

A mass transfer model applied to the supercritical extraction with CO2 of curcumins from turmeric rhizomes (Curcuma longa L)

Increasing restrictions on the use of artificial pigments in the food industry, imposed by the international market, have increased the importance of raw materials containing natural pigments. Of those natural substances with potential applications turmeric rhizomes (Curcuma longa L), are one of the most important natural sources of yellow coloring. Three different pigments (curcumin, desmetoxycurcumin, and bis-desmetoxycurcumin) constitute the curcuminoids. These pigments are largely used in the food industry as substitutes for synthetic dyes like tartrazin. Extraction of curcuminoids from tumeric rhizomes with supercritical CO2 can be applied as an alternative method to obtain curcuminoids, as natural pigments are in general unstable, and hence degrade when submitted to extraction with organic solvents at high temperatures. Extraction experiments were carried out in a supercritical extraction pilot plant at pressures between 25 and 30 MPa and a temperature of 318 K. The influence of drying pretreatment on extraction yield was evaluated by analyzing the mass transfer kinetics and the content of curcuminoids in the extracts during the course of extraction. The chemical identification of curcuminoids in both the extract and the residual solid was performed by spectrophotometry. Mass transfer within the solid matrix was described by a linear first-order desorption model, while that in the gas phase was described by a convective mass transfer model. Experimental results showed that the concentration profile for curcuminoids during the supercritical extraction process was higher when the turmeric rhizomes were submitted to a drying pretreatment at 343 K

Supercritical fluid extraction of vegetable matrices: Applications, trends and future perspectives of a convincing green technology

Along more than a decade, R\&D on supercritical fluid extraction (SFE) of vegetable matrices has been increasingly reported in the literature. Aiming at portraying the current state of this field and its evolution in terms of raw materials, products, modes of operation, optimization, modeling techniques, and closeness to industrial application, a large compilation of almost 600 essays from 2000 to 2013 has been deeply analyzed in order to unveil those indicators and their trends. Furthermore, strengths and weaknesses are identified, and some remarks that may drive upcoming research are provided. Globally, more than 300 species are reported in the literature, with prevalence of the extraction of seeds (28% of works) and leaves (17%). The main families of extracted compounds, cosolvents and operating conditions adopted are critically examined, being possible to conclude that researchers investigate many times working regions far from the optimum due to practical limitations or absence of experimental optimization. Current phenomenological, statistical and semi-empirical approaches are reviewed, along with scale-up studies, and economic analysis. In the whole, the most comprehensive picture over SFE of vegetable matrices is provided in this review, highlighting pertinent aspects and opportunities that may further consolidate the convincing route of this technology for the next years. (C) 2014 Elsevier B.V. All rights reserved