Obtenção e avaliação das frações lipossolúvel e hidrossolúvel de sementes de urucum (Bixa orellana L.) por tecnologia verde

Abstract

The search for the offer of new food products and the concept of clean labeling has further boosted the global market in the demand for natural ingredients and additives to replace synthetic ones. Among the ingredients, the colorants obtained from the seeds of the annatto (Bixa orellana L.) are industrially extracted by methods that have disadvantages, such as the degradation of thermosensitive bioactive compounds and the generation of harmful residues to the environment. In this context, the present study aimed to evaluate the efficiency of the process of obtaining simultaneous fat-soluble (FL) and water-soluble (FH) fractions of annatto seeds, by green technology, in terms of overall yield (mass), yield of pigments (bixin and norbixin) and bioactive compounds (total phenolics and flavonoids), antioxidant and antimicrobial activities and economic viability of the process. Three batches of annatto seeds

were submitted to the refrigerated solid-liquid extraction process, in four stages: pre- extraction, aqueous extraction, separation by decantation and filtration. The process was

efficient, in terms of overall average yield, FL = 8.68% and FH = 2.76%, and in terms of quality, mean lipid yields FL = 11.83%, bixin FL = 82.34% and norbixin FH = 29.59%, total phenolics (GAE) FL = 13.18% and FH = 23.48%, total flavonoids (RU) FL = 34.78% and FH = 5.70% and total flavonoids (CA) FL = 73.69% and FH = 18.48%. The composition of the fractions influenced the colorimetric attributes of FL, which showed greater intensity of red (a* ), associated with the content of lipids (r = 0.82) and bixin (r = 0.57), and of FH, which presented greater intensity of yellow (b*

), associated with the content of norbixin (r = 0.63) and total phenolics (r = 0.53). The higher concentration of norbixin and total phenolic, in the FH fraction, and bixin and flavonoids in the FL fraction, promoted an increase in the inhibition of free radicals (DPPH*

and ABTS*+) and of the ferric reducing power (FRAP), while the inhibition of thiobarbituric acid reactive substances (TBARS) was reduced to FL, which may be associated with the yield of lipids in this fraction. As for the antimicrobial activity, the FL extract presented a minimum inhibitory concentration (MIC) of 0.06 mg mL-1 for Staphylococcus aureus and 0.13 mg mL-1

for Salmonella Typhimurium and Salmonella Enteritidis, while the FH fraction did not inhibit the growth of the strains tested. The lowest costs were obtained for the FL fraction due to its higher extraction yield compared to the FH fraction. The extract production rate also increased with increasing scale and therefore the COM of the extract decreased. Plants in industrial scale of 1 and 10 L were considered economically unviable; however, 100 and 1000 L plant units achieved payback times of about 5 and 2 years, respectively. The fractions can be applied in the food industry as natural additives with coloring, antioxidant and antimicrobial functions, as a source of bioactive compounds in the preparation of nutraceutical and/or pharmaceutical products, and in the development of other innovative processes.