Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: March 30, 2009
Publication Date: April 5, 2009
Citation: Yuk,H-G.,Geveke, D.,Zhang, H. 2009. Supercritical carbon dioxide process for pasteurization of fruit juices [abstract].Conference of Food Engineering (CoFE 09).Columbus, OH. p.1. Technical Abstract: Supercritical carbon dioxide (SCCO2) nonthermal processing inactivates microorganisms in juices using non-toxic and non-reactive CO2. However, data is lacking on the inactivation of E. coli K12 and L. plantarum in apple cider using pilot plant scale SCCO2 equipment. For this study, pasteurized preservative-free apple cider was used. Cider inoculated with E. coli K12 or L. plantarum was processed using a continuous SCCO2 system at a CO2 concentration range of 0 – 12% (wt), temperatures of 34, 38, and 42 C, a system pressure of approximately 7.6 MPa, and a flow rate of 1 L/min. A control treatment without CO2 at 42 C and 7.6 MPa reduced the population of E. coli less than 0.2 log and had no effect on L. plantarum. Regardless of strain, higher CO2 concentration and temperature enhanced microbial reduction. Maximum log reductions were 7-log for E. coli K12 at 8% CO2 and 42 C, and 6-log for L. plantarum at 12% and 42 C. A 5-log reduction was obtained at each temperature for E. coli K12, while, for L. plantarum, a 5-log reduction was obtained only at the highest temperature, 42 C, indicating that E. coli K12 was more sensitive to SCCO2 processing. The degree of injury increased at higher CO2 concentration and treatment temperature, except for 42 C which resulted in less injury than other temperatures. These results demonstrate that the nonthermal SCCO2 process is feasible for pasteurization of apple cider.