91E-13 |
Chemical actinometry in UV treated juices |
C. ADHIKARI1, E. G. Murakami2, T. Koutchma1, and T. Beecham1. (1) National Center for Food Safety and Technology, Illinois Institute of Technology, 6502 S. Archer road, Summit Argo, IL 60501, (2) National Center for Food Safety and Technology, Food and Drug Administration, 6502 S. Archer road, Summit Argo, IL 60501 Ultraviolet radiation offers a nonthermal alternative to pasteurization of juices for microbial inactivation. Since UV dose determination using biodosimetric procedures is time consuming, chemical actinometry is the preferred choice. It offers a simple procedure that could help determine both absorbed and effective UV dose. Absorbed UV dose is dependent upon the absorption of the juice; while effective dose is based upon the destruction kinetics of the actinometer and can yield greater accuracy in dose measurements. The objective is to evaluate HHEVC ( 4,4',4''-tris-di-B-hydroxyethylaminotriphenylacetonitrile) dye as a chemical actinometer for determining effective UV dose delivered to apple juice. HHEVC was evaluated in a model juice system and in clear commercial apple juice at a concentration of 100 ppm. A simple spectrophotometric method measured the absorbance of the dye after UV exposure at 254 nm. The absorbance of the dye was measured at 600 nm. The sensitivity of the HHEVC to UV was greater than ferrioxalate, uridine or potassium iodide, standard chemical actinometers. The dose response plot of HHEVC dye was linear with an R2 of 0.99 (within 30 secs of UV exposure). Factors significantly affecting the ability of the dye to measure UV dose were pH and absorbance of either the model system or juice. The effective UV dose was calculated from the destruction kinetics of the dye and validated using ferrioxalate in a static system. From the correlation study of the effective dose response from HHEVC vs. ferrioxalate, the R2 value was 0.98. Effective dose was determined in static and a continuous UV reactor. The effective dose was significantly decreased when the model system or juice had absorbances at 254nm >0.4 or a pH >5.0. HHEVC dye appears useful as a dosimeter to determine delivery of an effective UV dose.
Session 91E, Nonthermal Processing: Nonthermal processing of foods
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