Effect of storage conditions on quality, microbial stability, and shelf-life kinetics of beetroot juice concentrate

Abstract

Beetroot juice (Beta vulgaris L.) with an initial 5.0 °Brix was concentrated to approximately 60 °Brix using forward osmosis (FO). The concentrate was then stored under ambient (25 °C ± 2 °C and 60–70% RH) and accelerated (37 °C ± 2 °C and 90% RH) conditions for 12 weeks. Throughout this period, physical, chemical, and microbiological properties were evaluated at two-week intervals. Results indicated that the quality of the beetroot juice concentrate (BRJC) was influenced by the storage environments over time, with minimal changes in pH, titratable acidity, and total soluble solids. However, betalain content and antioxidant activity were more sensitive to storage time and temperature. The degradation of betalains in ambient and accelerated conditions was 28.53% and 43.57%, respectively, at the end of 12 weeks of storage. The HMF and browning index (BI) levels of BRJC increased more significantly at 37 °C than at 25 °C. Betalain degradation followed first-order kinetics. Overall, the findings suggest that FO is an effective non-thermal method for concentrating beetroot juice as it preserves quality and extends shelf life. Additionally, a moderate to strong correlation was found between betalain content and total color difference in the BRJC stored under ambient and accelerated storage conditions.