Complexation of natural pigments with biopolymers: an approach to complexation techniques, binding parameters and application to food matrices

• Ano de defesa: 2022
• Autor(a) principal: Rocha, Felipe
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: eng
• Instituição de defesa: Universidade Federal de Viçosa; Ciência e Tecnologia de Alimentos
• Palavras-chave em Português: Pigmentos; Cor dos alimentos; Compostos bioativos; Biopolímeros - Reologia; Química, Física, Físico-Química e Bioquímica dos Alim. e das Mat.-Primas Alimentares
• Link de acesso: https://locus.ufv.br//handle/123456789/31502; https://doi.org/10.47328/ufvbbt.2022.444

Natural pigments are compounds that can present health-promoting bioactivities in the human body. Due to their coloring properties, these compounds have been widely used as color additives as an alternative to artificial colorants. However, since these pigments are unstable under certain conditions, such as the presence of light, oxygen, and heat, the complexation with a biopolymer is in demand. The complexation technique consists of forming a complex with the aim to make the compound less susceptible to oxidative and degrading agents. This work aims to discuss different techniques that have been used over the last years to create natural pigment-biopolymers complexes, as well as the recent advances, limitations, effects, and possible applications of these complexes in food systems. Moreover, the understanding of thermodynamic parameters between natural pigments and biopolymers to form a complex is very important. In this sense, the chapter 1 of this thesis presents a review about complexation techniques between natural pigments and biopolymers, and about thermodynamic techniques that can be used to determine binding parameters between natural pigments and biopolymers, as well as their applications, advantages, and limitations. The chapter 2 of this thesis presents the effects of natural-pigments-biopolymers complexes on food matrices, betalains (BE) nanodispersions were produced by using the solid dispersion method with polyethylene glycol (PBE) and with polyethylene glycol and low molecular chitosan (PCBE) by using the solid dispersion method followed by freeze drying. The thermal stability and stability of these pigments in acidic conditions were evaluated, as well as the effects of these nanodispersions on the color and rheology of Greek yogurt. Compared to pristine beetroot extract, PCBE nanoparticles presented increased stability for the main betalains in acidic conditions (pH 3.0 and 5.0) of 56% and 22%, respectively. Both PBE and PCBE showed enhanced relative thermal stability compared to pristine BE. Furthermore, PCBE improved commercial Greek yogurt's rheological properties and color parameters. PCBE nanodispersions can be successfully used as a color additive in the cosmetic, pharmaceutical, and food industries. Keywords: Color. Bioactive compounds. Thermodynamic properties. Rheology.