Modificações tecnológicas na rede de glúten que afetam a estrutura, digestibilidade e imunogenicidade

Author(s)

Ana Elisa Ramos Magalhães

• Document type: Master's Dissertation
• Press: Campinas, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Faculdade de Engenharia de Alimentos
• Defense date: 2023-03-09

Examining board members

Rosiane Lopes da Cunha; Ana Carla Kawazoe Sato; António Augusto Vicente

• Advisor: Caroline Joy Steel; Rosiane Lopes da Cunha

Abstract

The technological importance of wheat is mainly due to the viscoelastic properties of the gluten network, however, gluten exposure can induce adverse reactions in susceptible individuals. Wheat is usually consumed after some technological processing, which can affect gluten digestion and change the way gluten is recognized by the immune system. Several additives are used in baking to improve technological properties and product conservation. Ascorbic acid is used to strengthen the structure of the gluten network, contributing to the formation of crosslinkings between proteins through disulfide bonds. The use of vinegar, on the other hand, improves bread conservation, but can cause protein hydrolysis and weakening of the gluten network. The present study analyzed the effect of adding ascorbic acid or vinegar on rheological properties of the dough and on technological characteristics of the breads, which were submitted to an in vitro digestion and analyzed by confocal microscopy, SDS-PAGE and ELISA. The addition of ascorbic acid increased the resistance to extension (up to 63%) and storage modulus (G'), in addition to reducing the extensibility (up to 25%), indicating the formation of a more resistant dough. The analysis of the sulfhydryl content confirmed the increase in disulfide bonds promoted by the oxidizing agent. The addition of vinegar, on the other hand, contributed to a decrease in development time (up to 44%), stability (up to 20%) and viscoelasticity of the dough, with a decline in G'. These results were associated with the formation of a more open and less cohesive network, as observed in confocal microscopy. The digesta characterization showed that the generation of low molecular weight peptides started in the gastric phase. However, the electrophoretic profile of proteins throughout the digestion process was similar for bread prepared with different treatments. ELISA immunoassay suggested a reduction in gliadin content of about 44% in vinegar-treated samples compared to the control. This result indicates that the addition of vinegar can help in the hydrolysis of immunogenic gliadin sequences at the end of the digestion process. However, it is important to carry out further evaluations using other techniques to confirm the hypothesis. Keywords: gluten network structure, technological modifications, digestibility, immunogenicity (AU)

• FAPESP's process: 21/13311-0 - Gluten digestibility by dynamic in vitro simulation: impact of technological changes in bread
• Grantee: Ana Elisa Ramos Magalhães
• Support Opportunities: Scholarships in Brazil - Master