Antocianinas extraídas de capim-gordura (Melinis minutiflora): atividade antioxidante, microencapsulamento por atomização e estabilidade

• Autor(a) principal: Oliveira, Isadora Rebouças Nolasco de
• Data de Publicação: 2011
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/2903
• topic: Corantes naturais; Antocianinas; Estabilidade; Extração; Natural dyes; Anthocyanin; Stability; Extraction; CNPQ::CIENCIAS AGRARIAS::CIENCIA E TECNOLOGIA DE ALIMENTOS

Anthocyanins are unstable pigments which are present in vegetables such as grape, blueberry, strawberry, jabuticaba, red cabbage and others. Although there are many sources of anthocyanins, only few vegetables can be considered a commercial source. Therefore, the search for new sources with a low cost of extraction, as well as ways for stabilizing this pigment, has motivated the development of related researches. Molassesgrass (Melinis minutiflora) is a perennial mat grass viewed as a viable source of anthocyanins since it presents high content of this pigment, often superior than available commercial sources. Due to the instability of anthocyanins, conservation methods have been used to preserve the integrity of the pigment. The addition of antioxidants and encapsulation, using drying by atomization (spray dryer), are the most currently used conservation processes for their economical, flexible and continuous aspects. Thus, this study aimed to characterize the inflorescence of molassesgrass and evaluate the anthocyanins extracted as for the being tenor, antioxidant activity and stability of anthocyanins micro-encapsulate produced by different conditions of atomization. The plant anatomy showed that anthocyanin is present in the epidermal cells of glumes and lemma. The antioxidant activity was not influenced by the extraction solvent, however was a decisive factor when extracting anthocyanins and polyphenols, that the ethanol 70% was preterit due to were the most efficient and less toxic. In the production of powder extracts by spray dryer, the results indicated that the drying temperature exerted little significant influence on the observed responses, however the concentration of maltodextrin showed a significant effect on all studied responses: increased the temperature decrease was observed in the moisture content, water activity, anthocyanin retention and antioxidant activity (TEACABTS); increased the concentration of maltodextrin showed decrease all studied responses, except in the determination of color, in which the increase of maltodextrin produced lighter powders. A simultaneous analysis of all responses was performed and it was observed that the optimal atomization condition was reached with a temperature 170 °C and a maltodextrin concentration ranging from 5.5 %, under such conditions, particles with great coloring strength, high contents of anthocyanins and antioxidant activity, low hygroscopicity and moisture content were obtained. The anthocianins micro-encapsulate with 3%, 5.5% and 8% of maltodextrin dried 170 °C was submitted stability of light. During the stability study, the concentration of maltodextrin showed a good protective effect on the pigment since no significant loss in the anthocyanin content (average of 15.19%) and color (&#916;E* < 10) were observed when the samples were subjected to storage under light and dark. Time and concentration of maltodextrin had a significant effect on the antioxidant activity, showing that the higher the content of maltodextrin, the longer its protective potential. The light did not have any influence in the reduction of the antioxidant activity.