Elaboração e avaliação de Kombuchas análogas de erva cidreira (Melissa officinalis l.) e erva doce (Pimpinella anisum l.): Influência de substratos, adição de suco de acerola e aproveitamento de películas celulósicas

Abstract

Kombucha is a drink resulting from the fermentation of green tea and/or sweetened black tea and the addition of a culture containing a symbiotic consortium of bacteria and yeast. Increasing in the food market, it is known for contributing to the balance of the intestinal microbiota, as well as for its antimicrobial and anticancer properties. Therefore, the present work aims to prepare kombuchas with different substrates (green tea, lemon balm and anise) flavored with acerola juice, monitor the fermentation process, evaluate the chemical, microbiological and sensorial composition of the drinks, as well as make a product with the cellulose films resulting from fermentation. Three formulations were prepared with different infusions: T1 (green tea), T2 (lemon balm) and T3 (anise) containing 10 % (w/v) sugar which were fermented in a BOD oven, at 30 °C. For ten days, every 24 hours, pH, total soluble solids, titratable acidity, sugars, organic acids and ethanol were determined to monitor fermentation. After this step, clarified, pasteurized and sweetened acerola juice was added to all formulations and the drinks were subjected to a new fermentation, resulting in the kombuchas: K1 (green tea), K2 (lemon balm) and K3 (anise). The physicochemical, bioactive, color, stability, microbiological and sensory parameters were evaluated. The resulting cellulosic films were used to make straws and then the prototypes were evaluated for humidity, solubility, moisture absorption, predictions, and degradability. Anise-based kombuchas had the highest levels of total titratable acidity (T3 - 0.77 % and K3 - 0.64 %) and volatile acidity (T3 -144.14 mEq/L and K3- 144.14 mEq/ L). Regarding antioxidant capacity and phenolic content, both the addition of acerola juice and the second interference had positive effects on the accumulation of these bioactive compounds, being more relevant in samples K2 and K3. The addition of juice impaired the L* restrictions and increased the a* and b* restrictions in all treatments, reducing the ability of the drinks to incorporate the red color of the acerola. Sample T2 had better efficiency in the consumption of monosaccharides, while T3 presented higher concentrations of products (acetic acid, lactic acid and ethanol). The SCOBY yield after the first fermentation was higher in treatments T1 (121.29 %) and T3 (72.33 %). Regarding microbiological settings, the values of yeast, acetic bacteria and lactic acid bacteria varied between 10 3 and 10 5 CFU/mL. The kombuchas (K1, K2 and K3) did not make a significant difference (p ≥0.05) regarding the attributes evaluated for acceptability, except for the aroma attribute, which was also the only one that had an accessibility index of less than 70 % in K1 and K2. In CATA, the most suitable descriptors to characterize kombuchas were: “fermented aroma”, “acerola aroma” and “refreshing flavor”. In the RATA test, the attributes related to aroma were the most significant, but all had low intensity. Straws were produced from the cellulosic material resulting from the fermentation of kombuchas, which presented dimensions and properties compatible with use, good water absorption capacity, low solubility, and total handling after 45 days. In this way, the use of new infusions consists of alternatives to replace green tea in obtaining kombucha, and the addition of fruit juice in the second fermentation contributes to better accessibility of the drink and the increase of its bioactive characteristics. Furthermore, the sustainable nature of the drink stands out, as the production of biodegradable straws based on films presented with good recommendations.