Physicochemical and microbiological characteristics of kombucha based on various concentration of Javanese turmeric (Curcumaxanthorrhiza)

Abstract

This research proposed the usage of Javanese turmeric with various concentration as kombucha substrate to enhance Javanese turmeric bioactivity. The study used Randomized Block Design (RBD) with one factor of Javanese turmeric concentration (0.2%, 0.4%, 0.6%, 0.8%, 1%) with three replicates each. Javanese turmeric powder was made into solutions with determined concentrations, then fermented into kombucha (a beverage known for its health benefits) by SCOBY culture at room temperature for 12 days. Its physicochemical (pH, total titratable acid, total phenolic content, antioxidant activity) and microbiological characteristics was analyzed along with bioactive compound identification. Data was statistically analyzed with ANOVA (Analysis of Variance) and Fisher's exact test at p < 0.05. The best treatment was determined with Multiple Attribute Decision Making (MADM) method. Based on the analysis conducted, it is concluded that kombucha fermentation changed Javanese turmeric total microbial cells, pH, and total titratable acids as well as enhanced total phenolic content, improved antioxidant activity, and increased bioactive compounds. The best properties were found on kombucha with 0.4% (w/v) Javanese turmeric with the characteristics as follows: pH of 3.45 ± 0.02, total titratable acid of 0.21 ± 0.02%, total phenolic content of 89.852 ± 1.45 mgGAE/mL, antioxidant IC50 of 164.65 ± 6.01 ppm, and microbial content of 1.45 x 108 cfu/mL.