Changes of quality of high hydrostatic pressure processed cloudy and clear strawberry juices during storage

Changes of quality of cloudy and clear strawberry juices processed by high hydrostatic pressure (HHP) at 600 MPa/4 min during 6-month storage at 4 and 25 degrees C were investigated. After 6 months of storage at 4 degrees C, ascorbic acid, anthocyanins and total phenols decreased by 39.41%, 29.76% and 16.22% in cloudy juices, and by 48.91%, 7.02% and 13.82% in clear juices, but the antioxidant capacity in both juices decreased by less than 10%. The decrease of these indices at 25 degrees C for 6 months almost doubled. The lightness (L*) and redness (a*) in both juices at 25 degrees C were significantly lower than at 4 degrees C, while total difference color (Delta E) and browning degree (BD) were significantly higher. 66.93% and 70.75% decreases of viscosity and 47.60% and 79.98% of cloud in cloudy juices were observed after 6 months of storage at 4 and 25 degrees C, respectively. The loss of ascorbic acid, anthocyanins, total phenols and antioxidant capacity fits well to a first-order equation. Total anthocyanin content was selected as a biomarker to predict the shelf life due to their influence on the consumer acceptance and higher sensitivity to the storage temperature. Industrial relevance: Strawberry juice is one of the popular fruit juices, and it requires strict processing treatment and storage conditions to protect its quality. HHP is one promising novel non-thermal technique and is likely to replace thermal processes. A better knowledge of effects of storage temperature on the quality of HHP-treated strawberry juice and its shelf life prediction through kinetics analysis of these changes is necessary. This study would provide technical support for commercial application of the HHP technique in strawberry juice processing. (C) 2012 Elsevier Ltd. All rights reserved.