Research Information System
Turkish Journal of Engineering, vol.10, no.1, pp.283-293, 2026 (Scopus, TRDizin)
In this study, the changes in the chemical and physical properties of black mulberry juice during storage at different temperatures (4 °C, 20 °C, 30 °C, and 40 °C) over a period of 6 months were investigated. The study examined changes in pH, titratable acidity, Brix value, total phenolic compounds, antioxidant activity, sugar content, and bioactive components such as resveratrol. The pH value remained stable throughout the storage period, while a slight decrease was observed in titratable acidity. The Brix value also remained constant. The total phenolic compound content, which was initially 650.3 ± 0.4 mg GAE/L, decreased to 480.0 ± 0.5 mg GAE/L after 6 months at 40°C. Antioxidant activity decreased during storage, with the greatest reduction observed at 40°C. Sugar content increased due to the rise in glucose and fructose levels, while sucrose content rapidly decreased at higher temperatures. At 40 °C, sucrose became undetectable after 5 months. Resveratrol content also declined significantly during storage, particularly at elevated temperatures. Kinetic analysis revealed that resveratrol degradation followed first-order reaction kinetics. As storage temperature increased, the degradation rate constant (k) increased, while the half-life (t₁/₂) decreased from 55.88 hours at 4 °C to 5.25 hours at 40°C.