Physicochemical qualities of doenjang stew sauce prepared with fermented Rhus verniciflua extract during storage, and its comparison with commercial available products in the physiological activities

Abstract

Doenjang stew sauce was prepared with fermented Rhus verniciflua extract, and changes in its physicochemical quality were measured while stored at 25, 35, and 45°C for 8 weeks. The Rhus verniciflua doenjang stew sauce (RDS) was compared with commercially available products in antioxidant, antidiabetic (AGI) and antiobesity (PLI) activities. No aerobic bacteria, coliforms, and fungi were detected during storage, and the pH decreased and titratable acidity tended to increase with the storage period. On the other hand, the sugar content and salinity did not significantly change during storage. As regards chromaticity, a and b values decreased with the storage period, while L and ΔE values did not significantly change with storage. The pH, titratable acidity, and a and b values, which showed significant changes with the storage period, were selected as quality indicators. Based on the forecasted distribution day by annual temperature, the shelf life of Rhus verniciflua doenjang stew sauce (RDS), based on pH with the shortest shelf life among quality indicators, was predicted to be 13.38 months. A comparison of antioxidant activity of RDS and commercial doenjang stew sauce (DS) revealed that DPPH and ABTS radical-scavenging activities were significantly higher, at 71.17% and 78.20%, respectively. AGI and PLI activities were also significantly higher, at 55.99% and 35.98%, respectively.