Nádia Cristina Fernandes Corrêa

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.

Comparative study on the quality of oil extracted from two tucumã varieties using supercritical carbon dioxide

The vast Amazon region has considerable territorial peculiarities and plant species diversity, sometimes from the same botanical family, which can exhibit significant differences in physicochemical properties. From this diversity, two species stand out – Amazonas tucuma (Astrocaryum aculeatum Meyer) and Para tucuma (Astrocaryum vulgare Mart.). The research focus is to analyze, comparatively, these oleaginous fruits, their similarities, particularities and potentials regarding the oil quality extracted from two tucuma varieties from the states of Amazonas and Para, obtained using supercritical carbon dioxide, under different extraction parameters. The results demonstrate the biometric particularities of each species, highlighting the Amazon fruit, which also showed higher oil yield using supercritical CO2 extraction. The fatty acid quality and profile aspects of the oils show their unsaturated predominance, considering carotenoid content and how the extraction temperature can influence the nutritional quality of the oils. The statistical analyses indicated that the Amazon tucuma oil is superior to the Para tucuma oil. However, in terms of added value both oils have potential applications in various industrial segments.