The focus of this thesis is to develop pectin-based edible films for application of fruits and vegetables to extend their post harvest shelf life. Preliminary research demonstrated that edible coatings could effectively extend the shelf life of based avocado and peach. The respiration rate, moisture loss, firmness, chemical parameters and color changed in a lower rate in coated fruits as compared with the control. Pectin-based film formulations were then evaluated to identify the proper type and concentration of pectin, lipids and plasticizers in the film. The effects of pectin, beeswax and sorbitol concentration on water vapor permeability, mechanical properties and opacity of the films were then evaluated using response surface methodology to identify appropriate levels of different components. Results of studies on film structure revealed that water vapor permeability increased by pectin and sorbitol concentration and was decreased by beeswax concentration. Mechanical properties were mainly affected by pectin and sorbitol concentration. Beeswax was the most influential factor that affected opacity which increased with increasing beeswax concentration. / In order to successfully employ these films, their adsorption behavior, thermal and thermomechanical properties were evaluated as a function of moisture content and sorbitol concentration. The adsorption behavior was strongly influenced by sorbitol concentration. Moisture content and sorbitol concentration increased the films elongation at break, but decreased tensile strength, modulus of elasticity and Tg, and increased water vapor permeability of the films. Finally, avocado was coated with a pectin-based film and the associated quality changes were evaluated during storage. From storage studies, kinetic parameters (rate constants) and activation energy were quantified to help model the quality changes in avocado quality as function of storage temperature and time. Pectin-based coating resulted in slowing down the rate of quality changes in avocado at each storage temperature. In general, most changes were well described by some form of zero or first order rate. Temperature sensitivity of rate constant was adequately described by the Arrhenius model. / A hyperspectral imaging technique was also used to gather additional tools for following quality changes associated with stored avocados. Artificial neural network (ANN) concepts were evaluated as alternated models for predicting quality changes in coated and non-coated avocados during storage at different temperature. Modeling of quality changes in avocado indicated that compared to conventional mathematical models, ANN has more feasibility to predict of these changes. Models developed for firmness, weight loss and total color difference had better fitness than respiration rate. / Finally, the effect of coating on disease severity and different properties of avocados infected by Lasiodiplodia theobromae was studied. The coated fruits demonstrated slower rate of disease progress, respiration rate, softening and color changes. Respiration rate, firmness and color parameters were sensitive to coating and disease severity, and thus these parameters could successfully used to predict fruit quality from disease in coated and uncoated avocados.

Pacific oysters (Crassostrea gigas), Alaska pink salmon (Oncorynchus gorbuscha) roe and chum salmon (Oncorynchus keta) fillets were treated with aqueous ozone in both pilot plant and commercial settings to determine its effect on shelf-life and microbial changes. The microbial quality was analyzed by conducting pyschrotrophic and coliform plate counts on 3M petrifilm. Oxidative rancidity, pH and moisture were measured during the shelf-life study to determine the effects of ozone on quality. Concentrations of 0.5-1.3 ppm of ozone were applied for periods of 30 s, 1, 2 and 4 min at 5°C, 9°C and 15°C to determine an optimum ozone concentration and contact time that would decrease the seafood microbial load and increase shelf-life in the pilot plant studies. Oysters and roe were treated at 15°C and 5°C and fillets were treated at 9°C. There where only minor microbial differences between ozonated and non-ozonated samples. Treatment temperatures rather than treatment types affected the microbial load. The pilot plant experiments at 15°C and 5°C showed 1 log decrease in oysters and roe treated with aqueous ozone at variable concentrations. No increase in shelf-life was observed when salmon fillets were treated with aqueous ozone (1.3 ppm) for 2 min. Bacteria strains were isolated from treated (ozone and water) and control salmon fillet groups at 0, 5 and 10 days of storage and identified using the API20 NE system. The microbial change in the fillet flora did not differ between ozonated and non-ozonated treatment groups. Gram-positive bacteria were predominant in all groups at day 0, Pseudomonas flunrescens and P. putida were the predominant bacterial species found from all groups at days 5 and 10. Aqueous ozone (0.5-1.7 ppm) was applied in a commercial Ikura roe processing facility. A decrease in the microbial load was seen in the pre-processed samples which were ozonated with eggs in the skein. There were no differences in microbial loads from the non-ozonated and ozonated post-processed samples of individual eggs removed from the skein. / Graduation date: 2003

The storage life at 43°F of ground dover sole fillets (Microstomas pacificus) was determined microbiologically after treatment with ionizing radiation and antimicrobial agents. Sodium benzoate, potassium sorbate and the sodium salts of the methyl and propyl esters of parahydroxybenzoic acid (MPB and PPB) all approximately doubled the refrigerated storage life of irradiated dover sole. The dose levels employed were 0.1, 0.3, and 0.5 Mrad. The concentration of the agents used in each case was 0.1 percent. The normal spoilage of dover sole is caused predominately by the outgrowth of pseudomonads. After irradiation, however, the spoilage is due to the outgrowth of Achromobacter and certain Gram positive organisms. The spoilage pattern was not changed by the antimicrobial agents tested except at the higher dose level (0.5 Mrad), at which the spoilage was caused by yeasts. The additives had no effect on the growth rate of the microorganisms of dover sole. They merely prolonged the length of microbial dormancy that followed radiation exposure. Possible mechanisms involved in the combined effect of antimicrobial agents and irradiation are discussed. / Graduation date: 1965

Graduation date: 1951

Graduation date: 1961

Graduation date: 1963

Graduation date: 1942

Graduation date: 1992

Thesis (MRegionalUrbanPlanning)--University of South Australia, 2003.

Thesis (Master of City Planning) Georgia Institute of Technology, March 1991. / "March 6, 1992." Description based on title screen as viewed on April 8, 2009. Includes bibliographical references (p. 124-126). Also available in print.