Evaluation of quality changes of pressurized and pasteurized herbal-plant beverages during chilled storage

The physicochemical and microbiological qualities of pressurized herbal-plant beverage at 400 MPa and 25°C for 30 min and pasteurized beverage at 90°C for 2 min were investigated during storage at 4°C for 4 weeks. It was found that the brightness (L) of both processed beverages noticeably decreased (P 0.05) with an increasing storage time, while other parameters such as a* (reddish), b* (yellowish), ΔE (total different colors) and BI (Browning Index) were trended to increase. In addition, the bioactive components, i.e. ascorbic acid, γ-oryzanol, asiatic acid, gallic acid, ellagic acid and total phenols, and antioxidant capacity (DPPH assay) in both processed beverages significantly declined (P 0.05) throughout the entire storage. Overall the results displayed that pressurization could maintain the natural color and bioactive compounds of the product better than thermally process.