RT info:eu-repo/semantics/doctoralThesis
T1 High hydrostatic pressure as a technological tool for the development of gluten-free flours with improved
A1 Gutiérrez de la Fuente, Ángel Luis
A2 Universidad de Valladolid. Escuela de Doctorado
K1 Harina
K1 High hydrostatic pressure
K1 Altas presiones hidrostáticas,
K1 Buckwheat
K1 Trigo sarraceno
K1 Rice
K1 Arroz
K1 Gluten-free
K1 Sin gluten
K1 3309 Tecnología de Los Alimentos
AB Gluten-free (GF) staple food products, such as those from baking, are commonly presented with a low nutrient profile and are calorie-dense. The incorporation of nutrient-rich ingredients in the formulas, however, frequently led to physical and sensory impairments in the final products in spite of including structure-forming agents with the ability to mimic the gluten functionality. The aim of the present doctoral thesis is the study and evaluation of alternative and physically modified ingredients of high nutritional value for its inclusion in gluten-free baked product formulas.  Initially, the use of a low-cost by-product such as buckwheat (BW) hulls to increase the dietary fibre content of gluten-free bread was explored. In the experimental development, the use of two different particle sizes (62.7 µm vs 307 µm; D50) and two addition levels (3 – 6 %) of BW hull particles in a GF bread formulation was tested. The addition of BW hull particles in the GF rice-based bread formulation increased the viscoelastic moduli values of the doughs by increasing the percentage of addition and by using the smaller BW hull particle size. All the resulting breads showed a significant increase in dietary fibre content together with an increase in phenol content and antioxidant capacity. Furthermore, the addition of 3% of BW hull particles at the smallest particle size led to breads without alterations in physical properties and with appropriate sensory attributes.On the other hand, the physical treatment of high hydrostatic pressure (HHP) was also studied to promote tailor-made techno-functional properties in a whole flour making it suitable for GF baking products. In the initial stage of this study, the evaluation of combined treatments of pre-soaking (4h, 40ºC) and pressure application in a single or double cycle of the HHP treatment (600 MPa, 30 min.) on unhulled buckwheat (BW) kernels was carried out. The resulting flours obtained from the combined treatments showed higher water absorption capacity and thermal stability in the pasting profiles. A lower enthalpy of gelatinisation was also observed and attributed to partial gelatinisation induced by the treatments. These flours also showed higher phenol content. In the next stage, the influence of the HHP processing conditions of holding time (0/5/15 min.) and pressure level (300/600 MPa) on the unhulled and pre-soaked BW kernels was evaluated. The flours resulting from the most intensive treatment conditions (600 MPa, 15 min.) showed increasing values in hydration properties and higher thermal stability. In addition, they showed significant increases in antioxidant capacity. This flour was also used to partially replace white rice flour in a GF bread formulation. The resulting breads made with the modified BW flour showed higher specific volume and lower crumb firmness than their counterparts made with untreated BW flour.The combined treatments of HHP (600 MPa) with increasing holding times and pre-soaking were also applied to rough rice. Similar to the BW flours obtained after intensive HHP treatment conditions, the brown rice flours resulting from the combined treatments showed increased water absorption capacity and lower viscosity values in their pasty profiles with increased thermal stability. Increasing the treatment holding time resulted in an increase in phenol content, antioxidant capacity and vitamin content in the resulting flours. GF breads made by replacing white rice flour with HHP-modified brown rice (600 MPa, 15 min.) resulted in breads with higher specific volumes and softer crumb textures compared to those made with a native brown rice flour.Based on these results, this study shows that alternative approaches such as the inclusion of fibre-rich by-products or physically-modified GF whole flour ingredients from HHP treatments could be effective tools for technologically and nutritionally improving the quality of GF breads.
YR 2024
FD 2024
LK https://uvadoc.uva.es/handle/10324/69361
UL https://uvadoc.uva.es/handle/10324/69361
LA eng
NO Escuela de Doctorado
DS UVaDOC
RD 28-nov-2024