Effect of high pressure and thermal processing on quality changes of aloe vera-litchi mixed beverage (ALMB) during storage.

The effect of high pressure processing (HPP) (600 MPa/15 min/56 °C) and thermal processing (TP) (95 °C/5 min) on the quality characteristics of aloe vera-litchi mixed beverage samples (ALMB) stored at 4, 15 and 25 °C were studied. The total color difference and browning index of ALMB samples increased with the storage period for both HPP and TP treated samples under all storage conditions. HPP of ALMB resulted in inactivation of pectinmethylesterase (PME), polyphenoloxidase (PPO) and peroxidase (POD) to 34, 65 and 62 %, respectively after immediate processing, whereas, TP treatment lead to 83, 79 and 78 %, respectively. The residual activity of all the studied enzymes decreased with storage period. The ascorbic acid loss of up to 22 % was observed after HPP treatment and up to 31 % for thermally treated samples. Minimal changes were noted for phenolics content after HPP as well as thermal processing. The natural microbiota present in samples was below the detection limit (1 log CFU/mL) throughout the storage period. The shelf life of HPP and TP treated samples stored at 4 °C was estimated to be 100 and 80 days, respectively, based on the sensory quality, ascorbic acid degradation and instrumental color difference.