Aplicação dos tecidos florais de Handroanthus albus (ipê amarelo) e Tropaeolum majus (capuchinha) como substrato alternativo para a fermentação da kombucha

Abstract

The growing demand for functional foods has driven collaboration between the scientific community and the food industry in the development of innovative products with biological activity relevant to human health. Kombucha emerges as a fermented drink with promising characteristics to fill this gap. Its functional properties are associated with bioactive compounds synthesized during fermentation carried out by bacteria and yeast contained in the cellulosic biofilm (SCOBY). Improving the performance of these microorganisms and the bioactive characteristics of kombucha can be obtained with new alternative substrates for fermentation, such as edible flowers, which are a natural source rich in bioactive substances. Aiming to meet these demands, the present study aimed to develop kombuchas based on Camellia sinensis (black tea) with the addition of Handroanthus albus (yellow ipê) and Tropaeolum majus (nasturtium) petals, aiming to enhance the bioactive and functional properties of the drink. This investigation was consolidated into three substantial steps: optimization of black tea fermentation conditions; optimization of the extraction of bioactive compounds from H. albus petals and T. majus leaves and petals; and the fermentation kinetics of kombuchas with floral extracts. Response surface methodology suggested that the highest bioactivity of standard kombucha (100% black tea) can be obtained with a concentration of 12 g/L tea, 150 g/L sucrose at 23 °C. For the highest yield in the process of extracting bioactive compounds and antioxidant activity from H. albus petals, it was suggested the use of 80 g/L of floral tissue, at 90 °C for 15 minutes, and for T. majus, the parameters recommended were 60 g/L of flower, at 90 °C for 10 minutes. The best extraction conditions for nasturtium leaves were 8 g/L in 50% ethanol at 70 °C. The kombuchas with the addition of floral extracts showed a fermentative behavior analogous to that of the traditional drink, suggesting satisfactory microbial adaptation and compliance with the safety criteria established for the drink. The kombuchas added with H. albus enhanced the synthesis of glucuronic acid and added the compound β-lapachone, while the anthocyanin pigments from the petals of T. majus contributed to improving the antioxidant activity of the drinks. Nasturtium leaf extract showed a high concentration of bioactive compounds and antioxidant activity, being a favorable addition to increase the functional value of food products. Despite the differences observed between standard kombucha and those added with an alternative substrate, the floral tissues demonstrated favorable characteristics for the incorporation of new compounds into the drink, resulting in a final product with greater bioactivity and functional value.