Comparative Assessment of Semi-Industrial Thermal and Non-Thermal Pasteurization Technologies for Red Globe Grape Juice

TL;DR

This study compares different pasteurization methods for grape juice, finding that high-pressure processing best preserves color and quality, while ohmic heating offers good enzyme stability.

Contribution

The study provides a semi-industrial comparison of HPP, OH, and TP, focusing on quality preservation and microbial safety trade-offs.

Findings

High-pressure processing preserved juice color better than ohmic heating and thermal pasteurization.

Ohmic heating and thermal pasteurization achieved over 90% polyphenol oxidase inactivation.

Antioxidant capacity and anthocyanin content showed modest, non-significant changes across treatments.

Abstract

Nowadays there is a growing interest in alternative technologies to thermal pasteurization (TP) to ensure food microbial safety while minimizing effects on quality attributes like color, enzymatic activity, and bioactive compounds. However, direct comparisons of technologies are often limited to the prospect of microbial reduction levels. In this study, high-pressure processing (HPP), ohmic heating (OH), and TP were comparatively evaluated in red grape juice focusing on several parameters. Process conditions were selected to achieve a comparable 3-log reduction in total aerobic microorganisms as a benchmarking basis. OH and TP resulted in >90% polyphenol oxidase (PPO) inactivation, whereas HPP achieved ~30%. Instrumental color analysis (CIELAB) showed that HPP better preserved juice color, while OH and TP induced significantly darker products compared to fresh juice. Antioxidant capacity (FRAP) and total monomeric anthocyanin content showed modest, non-statistically significant changes across treatments. Conducted under semi-industrial conditions, this assessment highlights technology-specific trade-offs between enzymatic stabilization, color preservation, and bioactive retention. These findings suggest that HPP is superior for preserving heat-sensitive quality attributes, while OH offers an efficient thermal alternative to TP for achieving high enzymatic stability, providing a framework for industrial selection of preservation strategies based on product quality priorities.

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