FOOD. Science. Technology. Quality

Food. SCIENCE. Technology. Quality

Food. Science. TECHNOLOGY. Quality

Food. Science. Technology. QUALITY




Application of high hydrostatic pressures (UHP) to stabilize strawberry juices and nectars


The objective of this study was to determine the effect of high hydrostatic pressure (UHP) on the content of anthocyanins and colour characteristics of strawberry juices and nectars. The experimental material comprised strawberry juices and nectars produced by restoring the concentrated strawberry juice. Extracts (8 and 10 %) of the juice and nectar, respectively, as well as the acidity (5 g/l) and the content of fruit ingredient (40 %) in the nectar were determined in accordance with the ‘AIJN’ Code of Practice. The products made were stabilized in 180 ml jars (15 min., 85 ºC) using a traditional pasteurization method, and a high hydrostatic pressure (300 and 500 MPa) in polyethylene containers, during 5, 10, and 15 minutes, at a temperature of 50 ºC. All products were stored at a refrigeration temperature of 4ºC away from light. The juices and nectars were analyzed before the stabilization, immediately after the stabilization, and after their 30 and 60 day storage. In the juices and nectars, there were determined: the content of anthocyanins using a Fuleki and Francis method and the colour parameters in a CIE L*a*b* system. The high pressure applied had a positive effect on the content of anthocyanins in the two products immediately after the process accomplished, but the losses of those components during the storage were higher than in the traditionally pasteurized products. The UHP method used to stabilize the products permitted to more effectively stabilize the original colour of the juices and nectars immediately after the stabilization process and during the storage.


strawberry, juices, nectars, ultra high pressure (UHP)