Otimização da extração e microencapsulamento de polifenóis e antocianinas de jabuticaba (Myrciaria jaboticaba)

• Ano de defesa: 2011
• Autor(a) principal: Silva, Pollyanna Ibrahim
• Orientador(a): Stringheta, Paulo César
• Banca de defesa: Oliveira, Tânia Toledo de , Bertoldi, Michele Corrêa
• 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: Polifenóis; Extração; Microencapsulamento
• Palavras-chave em Inglês: Polyphenols; Extraction; Microencapsulation
• Área do conhecimento CNPq: CNPQ::CIENCIAS AGRARIAS::CIENCIA E TECNOLOGIA DE ALIMENTOS::CIENCIA DE ALIMENTOS
• Link de acesso: http://locus.ufv.br/handle/123456789/443

Anthocyanins belong to the flavonoids family and are responsible for most of the colors in flowers, fruits, leaves, stems and roots of plants. One of the most important properties of these pigments is their antioxidant activity, which is related to the prevention of several diseases. The jabuticaba is a fruit native from Minas Gerais state and, although widely consumed in Brazil, its phytochemical aspects are little studied. It is known that their skins are a source of anthocyanins and important phenolic compounds, which have high antioxidant activity. The study of bioactive compounds present in extracts of tropical and exotic fruits such as jabuticaba is important, since it could be feasible in addition to formulated foods and beverages. Therefore, this study aimed to optimize the extraction of bioactive compounds from jabuticaba, by assessing their behavior under different extraction conditions and to study the microencapsulation by spray-drying of anthocyanins from this fruit. In extraction studies, the bioactive compounds from jabuticaba were extracted with organic solvents (ethanol, methanol and acetone) and with aqueous sulfured solutions, using response surface methodology and central composite designs and, to evaluate, in the study of organic solvents, the effect of pH (2.9 to 7.1) and solvent concentration (39.6 to 100%) in total anthocyanins, total phenolic content, antioxidant activity and colorimetric coordinates L*, a*, b*, C* and h. In the study of aqueous sulfured solutions, the effect of SO2 concentration (93 to 1607 ppm), ratio solvent:skin (5 to 15 mL.g-1) and extraction time (3 to 12 h) were evaluated on the same responses. On the microencapsulation of anthocyanins from jabuticaba, optimization was performed using response surface methodology and a central composite design, analyzing the effect of different spray dryer feed flow (324 to 414 mL.h-1), defined by a previous screening study (evaluation of feed flows of 180, 360 and 540 mL.h-1), and the effect of inlet temperatures (144 to 180 ºC) on the responses anthocyanins retention, moisture content, hygroscopicity, overall difference of color, antioxidant activity and microstructure. Sorption isotherms were obtained using the powders from the screening study. In another study of microencapsulation of jabuticaba anthocyanins, the effect of different carrier agents (30% maltodextrin, a mixture of arabic gum 25% with 5% maltodextrin and a mixture of Capsul® 25% with 5% maltodextrin), and the effect of different inlet temperatures (140, 160 and 180 °C) were evaluated. The responses analyzed were anthocyanins retention, moisture content, hygroscopicity, overall difference of color, microstructure and solubility in model-systems of isotonic drinks. It was performed simultaneous optimization of the responses using the statistical function desirability. The results obtained on the extraction studies using organic solvents showed that the extraction of anthocyanins was more efficient when using methanol or ethanol 70%, at pH lower than 2.5, with the alternative of using pure solvents (100%) and neutral pH. Methanol 70%, in the conditions of this study, was the best extraction solvent. In the extraction study using aqueous sulfured solutions, it was found that the best condition to obtain the maximum of anthocyanins content and antioxidant activity was employing 900 ppm of SO2, during nine hours of extraction. In the study of optimization of microencapsulation by central composite design, it was found that the combination of higher inlet temperatures (> 170 °C) with lower feed flows (< 340 mL.h-1), and the association of higher feed flows (> 360 mL.h-1) with lower temperatures (150 ºC), promoted higher anthocyanins retention and lower overall difference in color. The GAB model was the best on the description of the sorption isotherms from the powders of screening experiments. In the study of microencapsulation employing various carriers agents and various inlet temperatures, using simultaneous optimization by desirability, it was found as an ideal condition of microencapsulation the use of carrier agent maltodextrin 30% and inlet temperature of 180 °C, in order to obtain powder pigments from jabuticaba that present, simultaneously, greater anthocyanins retention, minor difference in color, lower moisture content and lower hygroscopicity. The solubility of the powders in modelsystems of isotonic drinks did not vary between different carriers.