Combined Effects of Ultra-High Pressure Homogenization and Short-Wave Ultraviolet Radiation on the Properties of Cloudy Apple Juice

This work addresses the physicochemical, enzymatic and sensory changes in cloudy apple juice treated by ultrahigh pressure homogenization (UHPH) and short-wave ultraviolet radiation (UV-C) applied at 20 degrees C. Those technologies were applied in single and combined treatments at different UHPH pressures (200-300 MPa) and UV-C doses (14.3-27.8 J/mL). UV-C treatments could not effectively inactivate enzymes, but treatments at 300MPa UHPH reduced pectin methylesterase activity to a 24.6%, and polyphenol oxidase activity was not detected. Those samples presented a higher antioxidant capacity (283% measured by FRAP, and 286.4% by DPPH) than in non-treated juice, and after a combination with 28.7 J/mL of UV-C the polyphenols content augmented to 277.6%. Sensory evaluation revealed that UHPH at 300 MPa and UV-C at 21.5 J/mL significantly changed perceptible odour and overall flavour of cloudy apple juice, while treatments at 200 MPa didn't produce any significant changes in the different parameters. The results obtained in this study give a promising perspective of what a combination of both technologies can bring about in terms of obtaining stabilized fruit juices with improved antioxidant activity and polyphenol availability.