Kombucha de cajuína: produção e avaliação da atividade antioxidante in vitro

Abstract

Kombucha consists of a fermented beverage made with sweetened green (CV) or black (CP) tea, added to a symbiotic culture of bacteria and yeast called SCOBY (Symbiotic Culture of Bacteria and Yeasts). The result is a sweet, acidic and carbonated drink. There are reports that the drink has detoxifying properties and prevents digestive and circulatory problems. Cajuína (CAJ), is also a product valued for its antioxidant potential, in addition to its precious taste. It is a drink typically produced in the state of Piauí, through the clarification of pure cashew juice, without adding sugar or preservatives. This study proposes to produce CV and CP kombucha, adding to CAJ from a second fermentation and to evaluate the effects on the antioxidant activity of the products. After preparing the CV or CP, they were sugared and added to the SCOBY for initial fermentation (7 days) and secondary fermentation with CAJ (3 days). The lyophilized samples were diluted in different concentrations to evaluate the in vitro antioxidant potential: total antioxidant capacity (TAC), reducing power, hydroxyl radical (OH•) scavenging, superoxide radical (O2•-) scavenging and cupric chelation. The following were obtained: green tea kombucha (KCV); black tea kombucha (KCP) and green tea cashew kombucha (KCCV). KCV had a CAT of approximately 300 mg EAA/g. However, the CAT value in KCCV was lower than its control kombucha without cashew (KCV). However, in the test of reducing power, KCCV was more potent than KCV in the different concentrations tested (0.25 mg/mL; 0.5 mg/mL; 1 mg/mL). In the antioxidant assay of O2•- sequestration, values varied between 20% for CV and 30% for KCV (0.5 mg/mL). At this same concentration, all samples showed high percentages of OH• sequestration, reaching values for KCCV close to 100%. Regarding the chelating activity of copper ions, an activity of about 40% was observed for KCCV and 90% for the other samples, with no statistical difference between them. Therefore, the electron donating capacity (reducing power), OH• sequestration and cupric chelation were considered the main mechanisms of produced kombucha (KCV, KCCV). The study points to the need for more in-depth investigations in the phytochemical and biological scope of the products formed in fermentation