| Abstrak/Abstract |
Roselle-based kombucha offers potential as a functional beverage due to its bioactive compounds and antioxidant properties. This study aimed to optimize fermentation parameters, including roselle concentration, sucrose levels, and initial SCOBY mass, to enhance microbial activity and product quality. High-performance liquid chromatography identified chlorogenic acid (270.62 mg L⁻¹), quercetin-3-glucoside (31.96 mg L⁻¹), and rutin (7.7 mg L⁻¹) as predominant phenolics, with protocatechuic acid increasing over 14 days. Optimized conditions (5 g roselle, 12% sucrose, 25 g SCOBY) yielded superior SCOBY growth (41.66 g) and bioactive stability compared to traditional tea kombucha. Fermentation significantly influenced key parameters: pH remained stable (2.16 ± 0.02 to 2.21 ± 0.05) due to buffering organic acids, titratable acidity increased from 0.60% to 2.33%, and sucrose concentration decreased from 12.0 °Brix to 10.2 °Brix. Visual properties, measured using CIELab, showed dynamic changes, reflecting pigment degradation and transformation. Storage stability tests demonstrated that phenolic compounds remained stable at 4 °C, while room temperature storage increased phenolic content. Antioxidant activity assays confirmed robust activity, with IC50 values for DPPH (9.71 to 9.59 mg L⁻¹), ABTS (8.68 to 7.60 mg L⁻¹), and FRAP (10.01to 9.84 mg L⁻¹) showing stability in cold storage. These findings highlight roselle kombucha's potential as a nutritionally enhanced functional beverage, emphasizing its phenolic stability and antioxidant properties under optimized fermentation and storage conditions. The study provides practical insights for scaling production and improving cost-efficiency in functional beverage development. |
