Publicação
Development of bio-based micro- and nanostructures from milk whey proteins, as a vehicle for controlled release and delivery of bioactive compounds in food matrices
| Resumo: | β-lactoglobulin (β-Lg) is the major protein fraction of bovine whey serum and due to its gelation capacity, it has the ability to form micro- and nanostructures and entrap bioactive compounds. This thesis aims at providing information for the development and characterization of micro- and nanostructures from β-Lg, purified from a commercial whey protein isolate, to incorporate, protect and delivery of bioactive compounds with different water solubilities. The stability of β-Lg microand nanostructures was assessed under various environmental conditions as well as in food simulants and throughout an in vitro gastrointestinal model. Homogeneous and stable β-Lg structures were formed at pH 6 with thermal treatment at 80 °C for 15 min. In this conditions, β- Lg nanostructures (with diameter sizes ≤ 100 nm) and β-Lg microstructures (with diameters size between 200-300 nm) were formed with 5 mg mL-1 and 15 mg mL-1, respectively. Riboflavin and quercetin were used as hydrophilic and hydrophobic bioactive model compounds, respectively. The impact of environmental conditions (e.g. pH, temperature, ionic strength, and storage temperature) on stability of such structures were investigated. β-Lg structures maintaining their particle size, polydispersity index and surface charge under acidic, neutral or alkaline conditions, at thermal treatments up to 70 °C and during storage for 50 days. The release mechanism of bioactive model compounds from β-Lg structures a was assessed into two food simulants with different hydrophobicities under 4 °C and 25 °C, by fitting the Linear Superimposition Model to the experimental data. The relaxation is the main release mechanism of both bioactive model compounds. Caco-2 cell viability experiment demonstrated that riboflavin and quercetin at concentration up to 0.021 mg mL-1 and 0.016 mg mL-1, respectively, entrapped on β-Lg micro- and nanostructures did not have any impact on cell viability. In vitro gastrointestinal tract model showed that the entrapment of riboflavin and quercetin into β-Lg micro- and nanostructures increased stability, bioaccessibility, and bioavailability of both bioactive model compounds, when compared with these in their free form. In conclusion, strict control of the physicochemical conditions allowed the development of β-Lg structures with the desired characteristics and capable to act as delivery systems for hydrophilic and hydrophobic compounds, until the intestine. |
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| Autores principais: | Simões, Lívia de Souza |
| Assunto: | Whey proteins Bio-based structures Protein aggregation Delivery systems Food simulants Proteína do soro Base biológica Agregação proteica Sistema de entrega Simulante alimentar |
| Ano: | 2020 |
| País: | Portugal |
| Tipo de documento: | tese de doutoramento |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Universidade do Minho |
| Idioma: | inglês |
| Origem: | RepositóriUM - Universidade do Minho |
| Resumo: | β-lactoglobulin (β-Lg) is the major protein fraction of bovine whey serum and due to its gelation capacity, it has the ability to form micro- and nanostructures and entrap bioactive compounds. This thesis aims at providing information for the development and characterization of micro- and nanostructures from β-Lg, purified from a commercial whey protein isolate, to incorporate, protect and delivery of bioactive compounds with different water solubilities. The stability of β-Lg microand nanostructures was assessed under various environmental conditions as well as in food simulants and throughout an in vitro gastrointestinal model. Homogeneous and stable β-Lg structures were formed at pH 6 with thermal treatment at 80 °C for 15 min. In this conditions, β- Lg nanostructures (with diameter sizes ≤ 100 nm) and β-Lg microstructures (with diameters size between 200-300 nm) were formed with 5 mg mL-1 and 15 mg mL-1, respectively. Riboflavin and quercetin were used as hydrophilic and hydrophobic bioactive model compounds, respectively. The impact of environmental conditions (e.g. pH, temperature, ionic strength, and storage temperature) on stability of such structures were investigated. β-Lg structures maintaining their particle size, polydispersity index and surface charge under acidic, neutral or alkaline conditions, at thermal treatments up to 70 °C and during storage for 50 days. The release mechanism of bioactive model compounds from β-Lg structures a was assessed into two food simulants with different hydrophobicities under 4 °C and 25 °C, by fitting the Linear Superimposition Model to the experimental data. The relaxation is the main release mechanism of both bioactive model compounds. Caco-2 cell viability experiment demonstrated that riboflavin and quercetin at concentration up to 0.021 mg mL-1 and 0.016 mg mL-1, respectively, entrapped on β-Lg micro- and nanostructures did not have any impact on cell viability. In vitro gastrointestinal tract model showed that the entrapment of riboflavin and quercetin into β-Lg micro- and nanostructures increased stability, bioaccessibility, and bioavailability of both bioactive model compounds, when compared with these in their free form. In conclusion, strict control of the physicochemical conditions allowed the development of β-Lg structures with the desired characteristics and capable to act as delivery systems for hydrophilic and hydrophobic compounds, until the intestine. |
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