Tecnologia de Alimentos
URI permanente desta comunidadehttps://locus.ufv.br/handle/123456789/11783
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Item Interaction of cinnamic acid and methyl cinnamate with bovine serum albumin: A thermodynamic approach(Food Chemistry, 2017-05-26) Nunes, Natália Moreira; Pacheco, Ana Flávia Coelho; Agudelo, Álvaro Javier Patiño; Silva, Luis Henrique Mendes da; Pinto, Maximiliano Soares; Hespanhol, Maria do Carmo; Pires, Ana Clarissa dos SantosCinnamic acid (CA) and methyl cinnamate (MC) have attracted interest of researchers because of their broad therapeutic functions. Here, we investigated the interaction of CA and MC with bovine serum albumin (BSA) at pH 3.5, 5.0, and 7.4 using fluorescence spectroscopy, differential scanning nanocalorimetry, and measurements of interfacial tension, size, and zeta potential. BSA formed a complex with the ligands with stoichiometry of approximately 1.0. At pH 7.4, CA-BSA complex formation was entropically driven. The interaction between MC and BSA was more favorable than with CA and was enthalpically driven under the same conditions. The pH played an important role in BSA conformation, which altered the manner in which it interacts with the ligands. Interestingly, both CA and MC had no effect on the surface tension of BSA/air interfaces. These data contribute to the knowledge of CA/MC-BSA interactions and provide important data for application in the food industry.Item β-Carotene and milk protein complexation: a thermodynamic approach and a photo stabilization study(Food and Bioprocess Technology, 2017-12-02) Silva, Carla Eduarda Ladeira; Hudson, Eliara Acipreste; Agudelo, Álvaro Javier Patiño; Silva, Luis Henrique Mendes da; Hespanhol, Maria do Carmo; Barros, Frederico Augusto Ribeiro; Pires, Ana Clarissa dos Santos; Pinto, Maximiliano SoaresThe demand for bioactive molecules, such as β-carotene (β-car), has increased, but some characteristics such as low water solubility and low photo stability limit its application in many formulations. The bioactive entrapment into milk proteins may overcome this barrier. Thus, the aim of this work was to study the interaction between β-car and bovine serum albumin (BSA) or β-casein and the photo stability of this bioactive in the presence of the proteins. Fluorescence spectroscopy showed that at pH 7.0, increasing concentrations of β-carotene reduced the fluorescence intensity of both proteins, and the fluorescence-quenching mechanism is mainly static. The stoichiometry of the β-car/protein complex varied between proteins, being 1:1 to native BSA, 1:3 to denatured BSA (d-BSA), and 1:2 for β-casein. The standard Gibbs-free energy (ΔG°) of complex formation was negative for all systems studied and followed the order ΔG°BSA < ΔG°β-casein < ΔG°d-BSA. The formation of β-car/protein complex was driven by entropy increasing in all studied conditions. Both proteins improved β-car photo stability, but β-casein micelle was more efficient, reducing and increasing four times, respectively, the bioactive degradation constant and the half-time of β-car. The overall results pointed to the strategic use of milk proteins, especially β-casein micelles as nanovehicle for β-car in food and other systems.