Abstract
In this study, the changes in enzyme activities, total polyphenols, phenolic profile, and physicochemical properties from thermally (25–75 °C) and high-pressure carbon dioxide (HP-CO2) (25–65 °C/20 MPa)-treated apple juice were investigated. The HP-CO2 exhibited complete inactivation of polyphenol oxidase (PPO) at 65 °C, whereas PPO was still active at 75 °C under thermal processing (TP). Similarly, the relative activity of peroxidase (POD) significantly decreased by 71% at 65 °C under HP-CO2 processing, whereas TP was less effective. HP-CO2 and TP treatments at 65 °C reduced the browning degree (BD) value to 0.47 and 0.89, respectively. Thus, HP-CO2 inhibits the browning reactions caused by PPO and POD enzymes at each operating temperature. The concentration of epicatechin and catechin increased significantly with increasing temperature above 45 °C in TP-treated juices. HP-CO2 treatment increased the same phenolic compounds at 35 °C and 9 MPa, whereas high-temperature and -pressure conditions caused insignificant changes in concentration of epicatechin and catechin. Changes in others phenolic compounds were insignificant under TP and HP-CO2 treatment. Overall, HP-CO2 is a promising technology to get high-quality juices with lower enzyme activity.
Highlights
Apple is considered to be one of the most abundantly consumed fruits in the world
CO2 gas, distributing the carbonates and bicarbonates in the juice, thereby increasing the acidity and lowering the pH value of the juice. This finding was similar to our previous studies on carrot, quince, and apple juices, where pH was reduced under HP-CO2 treatment [11,20,22]
polyphenol oxidase (PPO) relative activity was lower for HP-CO2 treatment compared the increase in CO2 pressure is directly related to the PPO inactivation and browning inhibition under with thermal processing (TP), proving that HP-CO2 treatment was more effective at enzyme inhibition [10]
Summary
Apple is considered to be one of the most abundantly consumed fruits in the world. Apple juice is recognized as a health promoter because it contains a significant amount of nutrients and bioactive compounds such as polyphenols and organic acids [1,2]. Traditional juice processing causes the enzymatic browning of juices, which is related to the high activity of oxidoreductive enzymes such as polyphenol oxidase (PPO) and peroxidase (POD), due to fast degradation of polyphenols to quinones, which further leads to the formation of browning pigments [2,3,7,8] From this point of view, fast inhibition of browning reactions has gained much attention in the fruit and vegetable industry [3,9]. The present study was conducted to investigate the influence of different temperatures and pressures on the enzyme activity, quality characteristics, and bioactive compounds in treated apple juice For this purpose, a comparative study was performed to compare the efficiency of both thermal and HP-CO2 treatments in term of enzymatic inactivation, browning inhibition, quality attributes, and phenolic composition in apple juice. The phenolic profile of HP-CO2 -treated apple juice can be a fundamental theoretical guide for the commercialization of nonthermal technology
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
