Obtenção e caracterização de farinha de bagaço de uva e sua utilização em cereais matinais expandidos

• Ano de defesa: 2010
• Autor(a) principal: Ferreira, Luiz Fernando Dias
• Orientador(a): Pirozi, Mônica Ribeiro
• Banca de defesa: Chaves, José Benício Paes , Carvalho, Carlos Wanderlei Piler de , Correa, Paulo César
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Programa de Pós-Graduação: Doutorado em Ciência e Tecnologia de Alimentos
• Departamento: Ciência de Alimentos; Tecnologia de Alimentos; Engenharia de Alimentos
• País: BR
• Palavras-chave em Português: Fibra dietética; Fenólicos; Fortificação; Cereais matinais
• Palavras-chave em Inglês: Dietary fiber; Phenolics; fortification; Breakfast cereals
• Área do conhecimento CNPq: CNPQ::CIENCIAS AGRARIAS::CIENCIA E TECNOLOGIA DE ALIMENTOS::CIENCIA DE ALIMENTOS
• Link de acesso: http://locus.ufv.br/handle/123456789/428

Grape pomace, a wine making by-product accounts for 20% of the original weight of grapes. It is characterized by a high content of dietary fiber and phenolics with antioxidant capacity. The use of this residue for human consumption may represent a form of aggregating value to it, by converting it into a functional food. The objectives of this work were to study the behavior of thin-layer drying of grape pomace in heated air drier and to conduct a mathematical modeling by applying thin-layer drying models cited in the literature; to obtain the physical chemical characterization and antioxidant capacity of pomace flour of the grape variety Isabel (Vitis Labrusca) and its fractions (skin and seed); and to develop, produce and optimize an expanded breakfast cereal, using grape pomace. The drying experiments were conducted at temperatures of 50, 60, 70, 80 and 90 ºC, at a drying air velocity of 1.0 m/s. Ten different mathematical thin-layer drying models were compared, according to the values of the coefficient of determination (R2),qui-square (x2), residual mean square root (RMSR) and relative mean error (P), estimated by the drying curves. The effects of the drying temperature on the coefficients and constants were predicted by the regression models. The modified Page model was selected to represent the behavior of thin-layer drying of grape pomace. The model coefficients and constants can be explained by the effect of air drying temperature. To obtain the flour, the grape pomace was obtained from a wine production facility, dehydrated in a vertical drier by heated air at 60 ºC, and grouped into three materials: grape pomace, and their fractions: skin and seed, each being later ground and sieved. Determinations of humidity, proteins, lipids, ashes, crude fiber and carbohydrates (AOAC), total phenolic compounds (Folin-Ciocateau) and antioxidant activity (ABTS) were made for the three materials; pH determination and microbiological analysis (Bacillus cereus coliform at 45ºC, Salmonella and molds and yeast) were carried out in the grape pomace flour. The results showed that the grape pomace flour obtained has a high fiber content (21.89 g. 100g-1 of sample d.b.), with high antioxidant capacity (188 &#61549;mol Trolox.g-1 of sample d.b.). The microbiological analysis showed that the flour is safe for human consumption. The seed fraction has the highest content of total phenolic compounds and antioxidant capacity. The effect of the three ingredients, corn flour, grape pomace, and sugar, on the development of the breakfast cereals was investigated. A simplex-centroid design for pseudo-components was used to adjust empirical models to the physical and sensorial properties of the breakfast cereals. The (radial,longitudinal and volumetric)expansion indices, luminosity, the b value, and the flavor, texture, overall acceptance and purchase intention scores increased with increase in the proportion of corn flour in the mixture. The radial expansion index had a significant positive correlation (p < 0.01), with appearance, texture, overall acceptance and purchase intention. Greater overall acceptance, among the sensorial terms neither liked nor disliked and liked slightly was obtained with the formulation of 90, 6 and 4%, on a dry base, for corn flour, grape pomace and sugar, respectively. Extrusion did not affect the content of total phenolic compounds and reduced in 18% the antioxidant activity of the mixture of the central design point. This study showed that grape pomace flour can be used as an ingredient with functional claims up to 6% (d.b.) of addition, in the elaboration of corn-based breakfast cereals, with sensorial attribute of positive purchase intention.