Banca de DEFESA: RAUL COMETTANT RABANAL

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : RAUL COMETTANT RABANAL
DATE: 25/11/2022
TIME: 14:00
LOCAL: Acesso remoto
TITLE:

 Gluten-free whole grain breads produced with multicereal whole flours obtained by thermoplastic extrusion

KEY WORDS:

in vitro digestibility, Bioaccessibility, Bioactive compounds, Extrusion cooking, Multigrain, Rheology.

 

PAGES: 111
BIG AREA: Ciências Agrárias
AREA: Ciência e Tecnologia de Alimentos
SUBÁREA: Tecnologia de Alimentos
SPECIALTY: Tecnologia de Alimentos Dietéticos e Nutricionais
SUMMARY:

Bread is an ancestral product made from cereals such as rye, barley, eirkon, emmer, spelt and buckwheat; these grains were displaced by exaploid wheat (AABBDD) which has outstanding technological characteristics (tenacity, extensibility and viscoelasticity) which, years later with milling and sieving technology, became widely consumed as refined flour, mainly for the production of light white bread. Aiming to simulate these technological characteristics and trying to completely exclude wheat from bread formulations, in order to meet current demands, which are associated with diseases such as autoimmune diseases (celiac disease), non-celiac allergies and gluten sensitivities, which are triggered by the consumption of protein fractions (called gluten prolamins) intrinsically present in wheat, barley, rye and oats. In this sense, the use of gluten-free grains in their whole state offers an attractive alternative because they offer additional nutritional advantages by maintaining all their constituents such as fibre (soluble and insoluble), minerals, vitamins and phytochemicals compared to refined grains and their derivatives. In this context, the present work aimed to develop laboratory prototype gluten-free breads based on extruded whole grain flours from corn, rice, and sorghum, which was divided into four chapters. In chapter 1, a literature review was carried out on physical and thermal processes applied to gluten-free grains and flours to achieve certain viscoelastic properties that mimic wheat gluten free of chemical additives. The results in this field were scarce, showing that it is still a challenge to develop gluten-free breads free of additives (hydrocolloids and starches), therefore, thermoplastic extrusion technology is a promising technology that can transform native biopolymers into modified ones with techno-functional characteristics to be applied in the bakery and paste industry. The objective of chapter 2 was to use thermoplastic extrusion technology as a pre-treatment for whole grain flour (millet, parboiled brown rice and sorghum) and the incorporation of 5% germinated millet to produce gluten-free bread. The flours were characterized (chemical composition and granulometric distribution), the masses were evaluated (paste, rheological, empirical, and fundamental properties) and the quality characteristics of the bread were analyzed (physical, structural, and textural measurements). The thermoplastic extrusion allowed the development of consistency, better water absorption (105-153%) and viscoelastic properties of the dough. This process resulted in an increase of the specific volume (66, 33 and 82%, respectively for millet, rice and sorghum bread), and the formation of a better internal distribution of the air cell in the three different breads produced, especially in sorghum bread. In addition, the parboiled brown rice presented atypical paste and mass rheological properties, which also affected the quality characteristics of the bread. The incorporation of 5% sprouted rice improved the dough softness of the bread in all the samples, particularly for the extruded rice flour added with sprouted flour, which presented hardness (7.3 N) and elasticity (0.97) values similar to those of whole wheat flour. In chapter 3, we studied the functionality of flours pre-treated by non-conventional extrusion and the interactions between whole grain corn, parboiled brown rice, and sorghum cereals through the use of simplex-centroid mixture design, where we established treatments or formulations comparing pure flours, binary mixtures (two cereals) and ternary mixtures (three cereals) or also called multigrains. The results allowed us to establish that sorghum as pure flour was the cereal with the best characteristics in terms of volume and macrostructure compared to the other pure wholemeal maize and rice flours. The binary and ternary mixtures did not show considerable improvements, possibly due to the fibre content of the maize and the excessive consistency of the extruded parboiled rice. However, when the doughs obtained from the pure grains were mixed, improvements in the structure of the multigrain gluten-free bread millets were observed. Finally, chapter 4 studied the in vitro starch digestibility by determination of reducing sugars (RS) and the bioacceptability of bioactives in gluten-free breads by determination of total phenolic compounds (TPC), total condensed tannins (TCT), antioxidant capacity (ABTS+), as well as the quantification of phenolic acids and flavonoids of the gluten-free breads.

COMMITTEE MEMBERS:
Presidente - ***.412.587-** - CARLOS WANDERLEI PILER DE CARVALHO - EMBRAPA
Externa à Instituição - ELISA NOEMBERG LAZZARI KARKLE
Externa à Instituição - EVELINE LOPES ALMEIDA - UFRJ
Externa à Instituição - MARIA TERESA PEDROSA SILVA CLERICI - UNICAMP
Externa à Instituição - VANESSA DIAS CAPRILES - UNIFESP