Mild heat pasteurization, high pressure processing (HP) and pulsed electric field (PEF) processing of freshly
squeezed orange juice were comparatively evaluated examining their impact on microbial load and quality
parameters immediately after processing and during two months of storage. Microbial counts for treated
juices were reduced beyond detectable levels immediately after processing and up to 2 months of refrigerated
storage. Quality parameters such as pH, dry matter content and brix were not significantly different when
comparing juices immediately after treatment and were, for all treatments, constant during storage time.
Quality parameters related to pectinmethylesterase (PME) inactivation, like cloud stability and viscosity, were
dependent on the specific treatments that were applied. Mild heat pasteurization was found to result in the
most stable orange juice. Results for HP are nearly comparable to PEF except on cloud degradation, where a
lower degradation rate was found for HP. For PEF, residual enzyme activity was clearly responsible for changes
in viscosity and cloud stability during storage.
Industrial relevance: Development of mild processing technologies with a minimal impact on fruit juice can be
considered as a true alternative of fresh fruit. The present work presents a fair comparison of mild heat
treated, high pressure (HP) and pulsed electric field (PEF) processed orange juice as an alternative for thermal
pasteurization. Orange juices were monitored during two months of storage.