The Effect of Treatment Process and Brewing Temperature on Antioxidant Properties, Physicochemical Properties, and Sensory Profiling of Limeberry (Triphasia trifolia) Shoot Tea

Abstract

Limeberry (Triphasia trifolia), native to Southeast Asia, is consumed as an antioxidant-rich herbal infusion. This study aimed to (1) investigate the effects of pretreatment processes on the antioxidant, physicochemical, and sensorial properties of limeberry (T. trifolia) shoot tea, and to (2) determine the brewing temperature that maximizes antioxidant extraction, physicochemical properties, and the sensorial properties of limeberry (T. trifolia) shoot tea. Three processing treatments were conducted: Black Tea Fermentation (BTF), Green Tea Pan-frying (GTP), and Green Tea Steaming (GTS), brewed at 60 ̊C, 80 ̊C, and 100 ̊C. Physicochemical properties (pH, color, ̊Brix, moisture loss) (p > 0.05), antioxidant properties (TPC via Folin-Ciocalteu, DPPH radical scavenging) (p > 0.05), functional groups (FTIR), and sensory evaluations (9-point hedonic scale, Optimized Descriptive Profiling) were evaluated. TPC (104.87 - 440.73 μg GAE/g) and DPPH activity (30.80 - 49.97% inhibition) varied considerably but did not differ significantly (p > 0.05). All samples exhibited alkaline pH (7.68-8.52) and 0 ̊Brix consistent with the inherently low soluble solids of unsweetened tea. FTIR indicates the presence of O-H stretching, N-H stretching, and C=C stretching. In preliminary sensory screening, BTF was the only sample to surpass the 5.5 acceptability threshold. Among BTF samples, at 60 ̊C, the profile was the most acceptable (4.70 ± 1.95), though still below the threshold. Bitterness, astringency, and numbing sensations increased significantly with brewing temperature (p < 0.001). These findings suggest BTF at 60 ̊C as the most promising formulation, but further optimization is required to ensure acceptability.