Comparative effects of thermal, high-pressure processing, and pulsed electric field technologies on the quality attributes and bioactive compounds of sour cherry juice

This study aimed to evaluate and compare the effects of thermal treatment (TT), high-pressure processing (HPP), and pulsed electric field (PEF) technologies on the physicochemical properties, microbial stability, and bioactive compound retention in sour cherry juice. Treatments were designed to meet the requirement of a 5-log reduction in Escherichia coli ATCC8739 and to preserve the quality parameters of cherry juice. Colour parameters (L*, a*, b*, and ΔE*), apparent viscosity, microbial inactivation, total anthocyanins, phenolics, sugars, organic acids, and ascorbic acid contents were analyzed using one-way analysis of variance with multivariate evaluation using Principal Component Analysis (PCA). Thermal treatments caused significant colour degradation and loss of anthocyanins and phenolics, though they achieved complete microbial inactivation. HPP treatments, particularly at 600 MPa for 2 minutes, preserved colour and viscosity while achieving microbial safety requirements, but resulted in moderate anthocyanin loss. PEF treatments exhibited the highest retention of anthocyanins, ascorbic acid, and sugars, with PF 1.2 (22 kV/120 kJ/L) also achieving the required log reduction. PCA indicated that PC1 and PC2 accounted for 77.3% of the total variance, with PF 1.2 showing the best balance across nutritional and microbial safety parameters. Overall, the findings of this study demonstrated that PEF is the most promising technology for sour cherry juice processing, however it requires optimization for achieving microbial safety. HPP is a viable alternative since it caused moderate losses of bioactive compounds, while thermal processing, despite microbial efficacy, negatively affected cherry juice quality.