Title: Inactivation of microorganisms in apple cider and orange juice using supercritical carbon dioxide Authors
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: October 10, 2009
Publication Date: October 13, 2009
Citation: Geveke,D., Yuk,Hyun-Gyun, Novak,J.S., Zhang,H. 2009. Inactivation of microorganisms in apple cider and orange juice using supercritical carbon dioxide [abstract]. 2009 Beijing International Conference on Non-Thermal Processing Technologies. October 13-16, 2009. Beijing, China. p.1. Technical Abstract: Juice processors have traditionally used thermal pasteurization to prevent deterioration by spoilage bacteria such as Lactobacillus plantarum and Saccharomyces cerevisiae; however, thermal processing may cause adverse effects on product quality such as undesirable taste and destruction of heat sensitive nutrients. For this reason, nonthermal processing has been investigated as an alternative to thermal pasteurization. Of these nonthermal technologies, supercritical carbon dioxide (SCCO2) is one of the most promising because carbon dioxide (CO2) is a GRAS compound, inexpensive, and consumer friendly. The objective of this study was to evaluate the efficacy of SCCO2 for inactivating L. plantarum in apple cider as well as L. plantarum and S. cerevisiae in orange juice using a recently developed continuous system with a gas-liquid porous metal contactor. Experiments were performed using a CO2 concentration range of 0 – 12% (g CO2/100 g product), outlet temperatures of 34, 38, and 42 C, a system pressure of 7.6 MPa, and a flow rate of 1 L/min. Higher CO2 concentration and temperature significantly enhanced microbial inactivation of L. plantarum in apple cider, resulting in a 5.85 log reduction with 12% CO2 at 42 C. Similarly, a 5 log reduction of L. plantarum and S. cerevisiae in orange juice was achieved with 10% CO2 at 42 C. Morphological changes in SCCO2 processed cells were observed by SEM. SCCO2 treatment and refrigeration (4 C) effectively inhibited the growth of L. plantarum in apple cider during 28 day storage. Thus this study showed that SCCO2 treatment could be applicable for nonthermal pasteurization of apple cider and orange juice.