Possible nutritional and health-related value promotion in orange juice preserved by high-pressure treatment

Effects of high-pressure treatment on the orange juice carotenoids (beta-carotene, alpha-carotene, zeaxanthin, lutein and beta-cryptoxanthin) associated with nutritional (vitamin A) and health-related (radical-scavenging capacity) values were investigated. Various high-pressure treatments (50-350 MPa) combined with different temperatures (30 and 60degreesC) and times (2.5, 5 and 15 min) of treatments were assayed. The carotenoid content of the orange juice was analysed by HPLC-UV, the vitamin A value was determined as retinol equivalents (RE) and the free radical-scavenging capacity was evaluated using the DPPH (2,2-diphenyl-1,1-picrylhydrazyl) radical model system. A storage study was carried out at refrigeration temperature (4degreesC). High-pressure treatments at 350MPa produced significant increases of 20-43% in the carotenoid content of fresh orange juice (from 3.99 to 4.78-5.70mg l(-1)). A non-uniform behaviour of high-pressure treatments was detected. An increase in time (beyond 5 min) or temperature (above 30degreesC) of treatment did not improve the amount of carotenoids extracted. Owing to better extraction of carotenoids, an increase in vitamin A value from 164 to 238RE1(-1) (45%) was achieved with the 350MPa/30degreesC/5min treatment. No correlation was found between the increase in carotenoid amount extracted and the free radical-scavenging activity. (C) 2002 Society of Chemical Industry.