91E-22 |
Comparison of thermal processing and pulsed electric field for apple juice pasteurization |
A. V. CHARLES-RODRÍGUEZ1, S. Q. Li2, Q. H. Zhang2, and E. Ortega-Rivas1. (1) Graduate Program in Food Science and Technology, University of Chihuahua, University Campus I, Apartado Postal 1542-C, Chihuahua, Mexico, (2) Department of Food Science and Technology, Ohio State University, 2015 Fyffe Court, Columbus, OH 43210 Conventional pasteurization of fruit juices can cause significant loss of flavor and color change. Pulsed electric fields (PEF) is an emerging nonthermal food processing technology which can be applied in fruit juice pasteurization to minimize adverse changes in product quality. Comparison between PEF treatments and thermal pasteurization was conducted in apple juice to investigate quality changes and kinetics of inactivation of E. Coli. A PEF unit, developed at Ohio State University, was used in the experiments. E. Coli 8739 was incubated in Tryptic Soy Broth at 35°C for 8hrs. Cells were harvested by centrifuging at 5000 rpm for 5 minutes and then inoculated into the fresh apple juice. Samples before and after PEF treatments were collected for further analyses. Thermal treatments at different conditions were conducted using a continuous pasteurization treatment setup. PEF treatment at 33kV/cm electric field strength for 54 microseconds rendered more than 7-log reduction of E. Coli. Higher electric field strength resulted in a higher inactivation effect. Increased treatment time also increased the inactivation capacity. Furthermore, increasing the treatment temperature from 10°C to 40°C significantly increased the inactivation efficiency. No significant changes in pH, color and other quality attributes of apple juice were observed before and after the PEF treatment. Pertaining the thermal processing, microbial inactivation was also efficient and no significant quality changes were observed, although more variability was detected among treatments. Microbial inactivation efficiency of PEF treatment in apple juice was verified while some quality attributes were, practically, unaltered. PEF can be considerd an alternative for pasteurization of apple juice in order to obtain a high quality product.
Session 91E, Nonthermal Processing: Nonthermal processing of foods
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