U.S. flag

An official website of the United States government


Main content area

Nonthermal Processing of Orange Juice Using a Pilot-Plant Scale Supercritical Carbon Dioxide System with a Gas-Liquid Metal Contactor

Yuk, Hyun Gyun, Sampedro, Fernando, Fan, Xuetong, Geveke, David J.
Journal of food processing and preservation 2014 v.38 no.1 pp. 630
ascorbic acid, carbon dioxide, commercialization, heat, heat treatment, microbiological quality, nonthermal processing, orange juice, pH, pectinesterase, titratable acidity
This study compared the quality of fresh orange juice to that of supercritical carbon dioxide (SCCO2)-processed juice and equivalently thermally processed juice in terms of microbial lethality. A pilot-plant scale SCCO2 unit with a gas–liquid metal contactor processed juice with a CO2 concentration of ca. 8.5 wt % at 42C for 20 min. Thermal processing was conducted at 70C for 7.2 s. The number of naturally occurring microorganisms decreased from ca. 2.0–3.0 x 10³ to 18–28 cfu/mL after both SCCO2 and thermal processing. No noticeable changes in pH, °Brix, titratable acidity and ascorbic acid content were observed between processed and unprocessed juice. SCCO2 and thermal processing inactivated 46.5 and 86.4% of pectin methylesterase, respectively. The cloud stability of the SCCO2- processed juice was greatly enhanced compared with fresh and thermally processed juices. This study demonstrated that SCCO2 processing can improve the microbial quality of orange juice without deterioration, suggesting the potential for commercialization.