Date of Award

12-2014

Document Type

Thesis

Degree Name

Master of Science (MS)

Legacy Department

Packaging Science

Advisor

Dr. Kay Cooksey

Committee Member

Dr. Aaron Brody

Committee Member

Dr. Patrick Gerard

Abstract

This experiment sought to measure the changes in sensory quality that occur in tomatoes as the result of chlorine dioxide gas treatment. Tasti-Lee tomatoes (VFFF Hybrid #5755) were treated with two different levels of chlorine dioxide gas (10mg and 50mg of ClO2-forming material per kg of tomato) utilizing sachets. Testing compared the treated tomatoes and an untreated control group. These tests included flat-plate compression for firmness, sensory evaluation using a difference from control test, color analysis of the skin and flesh using a colorimeter, and enumeration of aerobic microbes and yeasts and molds. Flat-plate compression of whole tomatoes revealed no significant (p < 0.05) difference in firmness between treated and untreated tomatoes at the beginning (day 0) and end (day 17) of the experiment. Likewise, sensory analysis of cut tomatoes yielded no significant differences between treated and control tomatoes on day 0 or day 17. The colorimeter analysis showed a significant (p < 0.05) decrease in color index and increase in L* on day 0 as a result of the treatments. Color index also increased significantly in the two treatment groups from day 0 to 17, but it decreased for the control tomatoes. However, the sensory panel did not detect the initial or prolonged changes in the treated tomatoes. The 50mg/kg ClO2 treatment resulted in a 1 Log CFU/mL reduction in aerobic microbes on day 0, compared to the control group. This reduction in aerobic microbes was not residual, as the treatment and control groups had similar aerobic counts on day 7 and day 14. Overall, no practically significant negative effects (bleaching, phytoxicity, etc.) were initially measured in the tomatoes as a result of the chlorine dioxide treatments. Significant differences in rates of senescence between the treated tomatoes and the control tomatoes were not observed, giving no measurable indication that tomato shelf-life was extended as a result of the treatments.

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