Spectroscopic and photothermal characterization of annatto: Applications in functional foods

• Carotenoids were extracted from seeds of the tropical shrub Bixa orellana L.
• Bixin and norbixin carotenoids were extracted using chemical and aqueous processes.
• Absorption and fluorescence characterizations were obtained for natural dye.
• Thermo-optical characterizations were performed in annatto dye.
• Colorific was added to bread as a functional food application.

Dyes are among the most common additives used primarily to intensify, compensate or add color to manufactured products. The major color detected in annatto seeds comes from carotenoids bixin (C25H30O4) and norbixin (C24H28O4), depending on the extraction method. This article presents absorption and fluorescence spectroscopic characterizations of annatto extracted in aqueous solutions from seeds of the tropical shrub Bixa orellana L. Extractions from seeds were performed using aqueous solution (at 98 °C) with different potential of hydrogen values (pH 6.5–11.2), and the results were compared to those obtained with chemical extraction methods using other solvents. Thermo-optical parameters, such as refractive index temperature coefficient (dn/dT), thermal diffusivity (D), fraction thermal load (φ) and quantum yield (η) were determined for annatto solutions. Finally, the effectiveness of using of different concentrations of annatto dye in bread preparation is investigated as a functional food possibility.