Comparing the effects of high hydrostatic pressure and high temperature short time on papaya beverage

Inactivation of microorganisms in papaya beverage (PB) by high hydrostatic pressure (HHP) at different pressures (350, 450, 550 and 650MPa) and for different times (5 and 10min) was studied. Besides, the effects of HHP (550MPa/5min) and high temperature short time (HTST) (110 °C/8.6s) on microorganisms, total soluble solids (TSS), pH, color, total carotenoids, total phenols, antioxidant capacity, viscosity and sensory characteristics were comparatively studied immediately after treatments and during storage of 40days at 4 °C.HHP at 550MPa/5min inactivated microorganisms totally. The microbial safety in samples treated by HHP (550MPa/5min) and HTST (110 °C/8.6s) was ensured immediately after treatments during storage. TSS, pH, total carotenoids and viscosity experienced no significant impacts immediately after HHP and HTST treatments, while change of the original color and significant decreases of total phenols and antioxidant capacity were observed after HTST treatment. During storage, color changed and total carotenoids, total phenol, antioxidant capacity, viscosity and sensory evaluation decreased, whereas TSS and pH did not change. Kinetic data of changes in L*, a*, b*,ΔE* and antioxidant capacities measured by DPPH and FRAP methods fitted well into the combined model, while kinetic data of changes in total carotenoids and total phenols fitted well into the zero-order model. In both samples, total carotenoids and total phenols were positively and significantly correlated to antioxidant capacity. The HHP-treated sample showed higher total carotenoids content, total phenols content and antioxidant capacity, compared with the HTST-treated sample during 40-day storage.Papaya beverage, one of the most popular fruit juice products, is of high nutrition and economic value. This study presents a fair comparison between HHP- and HTST-treated papaya beverages immediately after processing and during storage. The available data show the different effects of HHP and HTST on quality and storage stability of microorganisms, color, antioxidant compounds, antioxidant capacity and other quality-related aspects. This study would provide technical support for the application of HHP or HTST in papaya beverage industry and the criteria establishment for commercial production of high quality papaya beverage. Besides, a non-thermal technique to meet consumers' growing demand for healthier food products is provided in this study.