Banca de DEFESA: BRUNO SÉRGIO TOLEDO BARBOSA

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : BRUNO SÉRGIO TOLEDO BARBOSA
DATE: 10/04/2026
TIME: 09:00
LOCAL: Remoto
TITLE:

Conjugates formed by egg white proteins and ferulic acid for application in delivery systems of hydrophobic bioactive compounds.

KEY WORDS:

Pickering emulsions; microencapsulation; vitamin D; β-carotene; bioactive films.

PAGES: 194
BIG AREA: Ciências Agrárias
AREA: Ciência e Tecnologia de Alimentos
SUBÁREA: Ciência de Alimentos
SPECIALTY: Química, Física, Fisico-Química e Bioquímica dos Alim. e das Mat-Primas Alimentares
SUMMARY:

The growing demand for functional and sustainable foods has driven the search for natural ingredients capable of providing health benefits beyond basic nutrition. In this context, proteins and phenolic compounds stand out due to their techno-functional and biological properties. Protein–polyphenol interactions may occur through non-covalent or covalent associations. Covalent interaction, also referred to as conjugation, results in irreversible structural modifications of proteins, affecting their solubility, emulsifying capacity, foaming properties, and antioxidant activity. Thus, the formation of protein–phenolic conjugates emerges as a promising strategy for obtaining novel food components with enhanced functionalities. This thesis aimed to develop and characterize conjugates formed between ovalbumin and lysozyme, the main egg white proteins, and ferulic acid, as well as to evaluate their application as emulsifying agents in Pickering emulsions for the delivery of bioactive compounds and subsequent incorporation into edible films. Conjugation promoted significant structural modifications in the proteins. In the case of ovalbumin, covalent conjugation with ferulic acid obtained by the alkaline method led to changes in secondary and tertiary structures, along with increased surface hydrophobicity, resulting in marked improvements in emulsifying and foaming capacities, as well as a statistically significant increase in antioxidant activity. For lysozyme–ferulic acid conjugates obtained by the free radical method, relevant structural modifications were also observed, leading to improved techno-functional properties. In addition, conjugation protected the antioxidant activity of ferulic acid after in vitro gastrointestinal simulation, indicating greater stability under digestive conditions. The conjugates proved to be effective alternatives as emulsifying agents in oil-in-water Pickering emulsions. Emulsions formulated with ovalbumin–ferulic acid conjugates exhibited good kinetic stability, with no phase separation for up to 8 days, and lower lipid oxidation compared with emulsions stabilized with native ovalbumin. For vitamin D encapsulation, a high encapsulation efficiency, 92.13 ± 1.14%, was achieved, contributing to the protection of the micronutrient against photochemical degradation. Pickering emulsions formulated with lysozyme–ferulic acid conjugates and loaded with β-carotene also showed high kinetic and oxidative stability, as well as an encapsulation efficiency of 88.99 ± 2.02%. The incorporation of these emulsions into pectin-based films modified the structural and barrier properties of the material. Films containing microencapsulated β-carotene exhibited a characteristic yellowish coloration, enhanced light barrier properties, reduced water vapor permeability, and lower water solubility. The addition of the emulsions increased the surface hydrophobicity of the films. β-Carotene release was described by the Ritger–Peppas and Peppas–Sahlin models, with Fickian diffusion behavior. Overall, the results demonstrate that protein–ferulic acid conjugation is an efficient strategy for developing multifunctional components with potential applications in functional foods and bioactive packaging

COMMITTEE MEMBERS:
Presidente - ***.548.996-** - EDWIN ELARD GARCIA ROJAS - UFF
Interna - 2563412 - TATIANA SALDANHA
Interno - 1231744 - YAGO ALVES DE AGUIAR BERNARDO
Externo à Instituição - CÉSAR AUGUSTO SODRÉ DA SILVA - UFV
Externa à Instituição - RENATA VALERIANO TONON - EMBRAPA