Desenvolvimento e caracterização de kombucha obtida a partir de chá verde e extrato de erva-mate : processo artesanal e escala laboratorial

Abstract

Kombucha é uma bebida resultante da fermentação de chá verde e/ou chá preto adoçados e adicionados de uma cultura contendo um consórcio simbiótico de bactérias e leveduras. Por possuir compostos bioativos similares ao chá verde e ter grande importância socioeconômica no Sul do Brasil, a erva-mate (Ilex paraguariensis St. Hil.) pode ser uma alternativa mais viável na produção de kombucha. Assim, o presente trabalho teve por objetivo a produção de kombucha utilizando a erva-mate como substrato alternativo em escala artesanal e laboratorial, comparando seus compostos e comportamento ao longo da fermentação à kombucha tradicional de chá verde. As kombuchas foram reproduzidas em escala artesanal, à temperatura ambiente, e em escala laboratorial, utilizando um biorreator com controle dos seguintes parâmetros: temperatura em 28 °C, agitação 50 rpm e aeração de 0,42 vvm para as kombucha de chá verde e erva-mate durante 7 dias de fermentação. As análises realizadas nas kombuchas de ambos os substratos foram: pH, fenólicos totais, atividade antioxidante e conteúdo de ácidos e açúcares, e somente para a kombucha de erva-mate foi realizada também análise sensorial. As kombuchas desenvolvidas obtiveram resultados satisfatórios com relação aos seus compostos bioativos, cujas versões laboratoriais apresentaram valores superiores tanto para fenólicos totais como para atividade antioxidante, demonstrando uma melhor extração destes compostos nas condições utilizadas no biorreator.

Kombucha is a beverage resulting from the fermentation of sweetened green or black tea by a microbial culture composed of a symbiotic association of bacteria and yeasts. Because of its composition containing bioactive compounds, similar to green tea, and its great socio-economic importance in the South of Brazil, leaves of mate ((Ilex paraguariensis St. Hil.) can be a viable alternative in the production of kombucha. Therefore, this work aimed at producing kombucha using mate as an alternative substrate in both artisanal and laboratory scale, and comparing its composition throughout the fermentation to the traditional kombucha of green tea. The kombuchas were produced in artisanal scale at room temperature and in laboratory scale using a bioreactor with control of the following parameters: temperature at 28 °C, agitation at 50 rpm, and aeration of 0.42 vvm for the green tea and mate for 7 days of fermentation. The kombucha analyses of both substrates were: pH, total phenolics, antioxidant activity, and content of acids and sugars, and, only for the mate kombucha, a sensory analysis was also performed. The developed kombuchas obtained satisfactory results regarding their content of bioactive compounds, the laboratory-produced showing higher values for both total phenolics and antioxidant activities, demonstrating a better extraction of these compounds under the conditions used in the bioreactor. Regarding the analyzes of pH and content of acids and sugars, the kombuchas of mate showed a lower conversion of sucrose in to its by-products of the fermentation, and a lower pH decrease when compared to the kombucha of green tea, possibly because the original microbial community was not adapted to that substrate. Sensory analysis of the artisanal kombucha resulted in 68.25% of global approval, whereas laboratory kombucha obtained 63.17% of approval. Moderate acceptance of kombucha was probably due to the lack of knowledge of this beverage among most the tasters, as well as the fact that it was offered without flavoring and carbonation, as the commercial versions are presented. Kombucha is growing in the national market and this work helps in a better evaluation of this product, allowing future studies that could help the characterization of kombucha for a possible standardization of its production on an industrial scale.