Banca de DEFESA: CRISTIANY OLIVEIRA BERNARDO

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : CRISTIANY OLIVEIRA BERNARDO
DATE: 17/07/2020
TIME: 08:00
LOCAL: Remoto
TITLE:

Elaboration and physicochemical and sensory characterization of chocolate powder with extruded whole sorghum flour

KEY WORDS:

agglomeration, glass transition, wettability

PAGES: 148
BIG AREA: Ciências Agrárias
AREA: Ciência e Tecnologia de Alimentos
SUBÁREA: Tecnologia de Alimentos
SPECIALTY: Tecnologia de Produtos de Origem Vegetal
SUMMARY:

Sorghum is a gluten-free cereal, and sorghum types with colored pericarp and their products may contain higher phenolic compounds levels and antioxidant capacity than others cereals. However, in Brazil, this cereal has been used mainly for animal feed. Their use in the diet of Brazilians requires the development of products that attend the consumer's needs and preferences, for this reason, it is important the sensory evaluation. It is also necessary to evaluate the technological process to obtain an accepted product. The aim of this study was to develop a chocolate powder using pre-cooked whole sorghum flour by thermoplastic extrusion (FES) and to evaluate the effects of the ingredients, as well as agglomeration conditions on the physical and sensory characteristics of this product. This thesis was divided into five chapters. In chapter 1, a bibliographic review was carried out, with following subjects: sorghum, cereal drinks, thermoplastic extrusion, agglomeration, and main instantaneous' characteristics. Chocolate powder is a viable product to popularize sorghum in human food in Brazil, due to its high consume by the Brazilian population. However, product quality depends on the processing conditions, type of equipment and ingredients. In chapter 2, six sorghum genotypes were compared regarding their chemical characteristics (after milling); sensory and preparation characteristics (after extruded and milling), as well as an online questionnaire, was applied using the terms ―cereal sorghum‖ and ―cereal beverage‖ as stimuli for the word association method. BR305 genotype presented highest phenolic compounds, antioxidant capacity, resistant starch and condensed tannin, while BRS373 and SC319 presented best molhabillity, dispersibility and sensory characteristics, therefore it was recommended to mix two or more genotypes. Word association made it clear that Brazilians do not know sorghum; however, they demonstrated good expectations regarding this cereal, especially the people who have some type of food restriction. In chapter 3, acceptance and sensory characterization of different powder chocolate formulated with FES were evaluated, as well as the effect of agglomeration parameters on physical characteristics of this chocolate powder. There were the highest sensory acceptance scores of chocolate powder with FES when people were informed about sorghum benefits and lower sugar content than commercial chocolate powder. The best condition for agglomeration processing, using the shortest wetting time as a criterion, was: 394g / min (flow rate), 1.6 (x102 kPa) (vapor pressure) and 74 ° C (drying temperature). In chapter 4, four maltodextrins and five modified starches were compared as ingredients on agglomeration of powdered chocolate containing FES, as well as a new method to analyze wettability was proposed. Maltodextrin (equivalent dextrose 5) and modified cassava starch provided the greatest instantaneity in the agglomerated chocolate powder. Principal component analysis applied to drop volume over time described the wettability of chocolate products. In chapter 5, the effects of FES, sugar, and maltodextrin on physical and sensory characteristics of chocolate powder were evaluated. Sugar positively affected sensory acceptance, but its increase contributed to obtaining granules above 850 µm with a cylindrical shape, which presented a longest dissolution time. FES also contributed to the largest granules size. Considering high sensory acceptance score, the optimal formulation found by desirability function analysis was: 20% FES and 60% sugar.

BANKING MEMBERS:
Presidente - 105.290.788-13 - JOSÉ LUIS RAMIREZ ASCHERI - UNICAMP
Interna - 2311373 - MARIANA TEIXEIRA DA COSTA MACHADO
Externa à Instituição - ELAINE SOUZA CÓCARO
Externa à Instituição - EVELINE LOPES ALMEIDA - UFRJ
Externa à Instituição - FERNANDA ZARATINI VISSOTTO