Antioxidant dye and pigment extraction using a homemade pressurized solvent extraction system

Abstract

Increases in reports of health hazards and toxicity of synthetic colorants are driving the food industry towards applying natural colorants to an increasing number of processed food products. The attention that natural dyes and pigments are getting is due to the functional properties attributed to some of these colorants. Although synthetic dyes and/or pigments have lower production costs and greater stability, the number of synthetic additives permitted in developed countries is decreasing every year; this increases the usage of antioxidant colorants, such as carotenoids and anthocyanins by the food processing industries. Commonly, conventional extraction methods are used to extract these compounds from natural sources. Nevertheless, these methods are, in general, time- and solvent-consuming and may promote the degradation of these compounds. To overcome these drawbacks, conditions of short extraction times using environmentally friendly pressurized solvents, such as supercritical CO2 and pressurized ethanol, have been successfully used to obtain antioxidant dyes and pigment-rich extracts. The objective of this work was to validate a homemade pressurized solvent extraction system that can be independently used for supercritical fluid extraction (SFE) and pressurized liquid extraction (PLE) processes. Functional colorant sources, such as annatto seeds and jabuticaba skins, were used as model plant materials. Our SFE results were compared to those obtained using commercial SFE unit with the same processing conditions to validate the new system. To establish the statistically significant differences or similarities between the SFE yield values, a Tukey's test was utilized. A confidence coefficient of 95% was used to compare the means. The anthocyanin content of the Jabuticaba skin extract obtained by the PLE method was determined using the pH differential method. The supercritical extracts from Jabuticaba skins obtained in a previous study in our laboratory study with pressurized ethanol were fractionated by thin-layer chromatography (TLC).