Abstract

High hydrostatic pressure (HHP) was applied on a white grape juice concentrate (GJC) to evaluate its effectiveness and possible application as an alternative to thermal pasteurization. GJC was processed at pressure levels of 200, 300, and 400 MPa for 2 and 4 min at room temperature (20 +/- 2 degrees C) and changes in various quality parameters after HHP processing and after subsequent storage at 4 degrees C for 35 days were examined. The effect of the HHP treatments on the conidial fungiBotrytis cinereawas determined after inoculating the GJC with a conidial suspension. The results shown a significant reduction ofB. cinerea(ufc/ml) at 400 MPa/4 min, in day 0 and after 35 days of storage sample. The physicochemical analysis of GJC showed that the sugar contents increased after treatments but decreased during storage. The total antioxidant activity and total flavonoid content in HHP-treated samples were significant decreased. Practical applications HHP processing of concentrated grape juice has proved to be efficient to retain content of antioxidant compounds and activity as well as characteristic quality of the GJC that is widely used in blending of fruit juices or as a natural sweetener in various food products. The experimental results have shown that HHP process could be a valid alternative to thermal pasteurization of GJC.