Thesis (Ph.D.)--University of Hawaiʻi, 2000. / Chairperson: Brian Murton. Includes bibliographical references.

Freezing is one of the important technologies for preservation of foods. In this project, using surimi as a food model, thermophysical properties of frozen foods were evaluated and the freezing process was simulated using a finite element package. To measure temperature-dependent thermal conductivity, a line-source probe system was used. Effects of test conditions and sample history were investigated. Thermal conductivity of Alaska pollock (Theragra chalcogramma) surimi having 0, 4, 6, 8, and 12% cryoprotectant levels was measured in the range of -40 to 30 ° C. Other thermal properties were analyzed using differential scanning calorimetry (DSC) at the same cryoprotectant concentrations and in the same temperature range. Each dynamically corrected DSC thermogram was used to determine initial freezing point, unfreezable water (bound water), apparent specific heat, enthalpy and unfrozen water weight fraction. When water content of the sample is controlled, thermophysical properties of surimi have a relatively weak dependence upon cryoprotectant level in the unfrozen and fully frozen (-40° C) ranges. However, the initial freezing point and the properties just below this point were significantly affected. From measured data, the Schwartzberg thermal property models for frozen foods were investigated. The models agreed well with experimental data. However, possibility for further improvement is demonstrated by using DSC analysis. This research additionally demonstrated the great potential of DSC for measuring and modeling frozen food thermal properties. Using the derived property models, a commercial PC-based finite element package was used to simulate the process of freezing a food block in a plate freezer. The capability of the program to handle temperature-dependent thermal properties and time-dependent boundary conditions enabled a simulation which accounted for measured changes in thermal properties, ambient temperatures and overall heat transfer coefficient. Predicted temperature history agreed well with measured data. Sensitivities of important model parameters, which were varied within their experimental error range, were also investigated using a factorial experimental design method. The result showed that in decreasing order of influencing freezing time prediction, attention should be given to apparent specific heat, block thickness, overall heat transfer coefficient, ambient temperature, thermal conductivity, and density. / Graduation date: 1991

Thesis (Ph. D.)--University of Washington, 2001. / Vita. Includes bibliographical references (leaves 155-167).

Thesis (M. Sc.)--University of Hong Kong, 2001. / Includes bibliographical references (leaves 69-79).

Thesis (Ph. D.)--University of Washington, 2003. / Vita. Includes bibliographical references (leaves 173-195).

The following three essays present an analysis that combines well-known models of fisheries management with contemporary theories of international trade and industrial organization. The general theme of the thesis is that countries' fisheries management policies can affect the strategic interaction between their fishing industries. The first essay examines the problem of noncooperative management of international fisheries by analyzing the strategic rent-shifting roles for such well-known national management policies as fleet licensing and effort subsidies. It is shown that the noncooperative equilibrium in each policy takes the form of a prisoner's dilemma with dissipated rents in the fishery. It is also shown that strategic effort subsidies can only lead to incomplete rent dissipation but strategic fleet licensing can lead to complete rent dissipation. The second essay develops a theory of cooperative management of international fisheries by considering negotiation between countries over the same fleet licensing and effort subsidy policies considered in the first essay. The outcomes of negotiation over these policies are compared to the corresponding noncooperative outcomes, on the one hand, and to the efficient outcome on the other. It is shown that negotiation over effort subsidies in the absence of side payments is efficient, but negotiation over fleet sizes in the absence of side payments is inefficient. The third essay develops a two-stage two-period model of a 'domestic' country and a 'foreign' country whose respective fishing industries harvest from separate fisheries for the same international market. The domestic country uses a harvest policy to regulate the harvest by its fishing industry, but the harvest by the foreign fishing industry is unregulated. Two types of fisheries are considered. In the case of schooling fisheries, the domestic country may choose a conservative harvest policy in the first period if it can induce the biological collapse of the foreign fishery in the second period. In the case of search fisheries, the domestic country always chooses a conservative harvest policy in the first period in order to induce the economic degradation of the foreign fishery in the second period. The results suggest that international fisheries trade in the presence of divergent national fisheries management regimes could have unexpected consequences for world fisheries.

Formulation studies of value-added seafood nuggets were done using appropriate mixtures of surimi, kamaboko, broken shrimp, and shrimp broth made from shrimp processing waste. A total of 19 formulations were prepared and, on the basis of sensory analysis, two formulations (comprising of 75% surimi: 25% shrimp, and 100% surimi containing shrimp broth) were used throughout this study. / Initial storage trials of both raw and cooked battered and breaded value-added nuggets in air and under various modified atmospheres (MAP) showed that a microbiological shelf-life of 28 d was possible for cooked nuggets at 4 and 12$ sp circ$C packaged under various gas atmospheres, compared to $ sim$14 d for raw nuggets stored/packaged under similar conditions. / Growth of Listeria monocytogenes occurred in both raw and cooked nuggets at 4 and 12$ sp circ$C, irrespective of packaging conditions. However, growth of Clostridium botulinum type E was inhibited in both raw and cooked nuggets stored at 4, 12, and 25$ sp circ$C. While inhibition was suspected to be due to the decrease in pH of raw nuggets to $ sim$4.1-4.5, due to the growth of lactic acid bacteria (LAB), subsequent studies on cooked and sterilized nuggets showed that the anti-botulinum effect was due to heat resistant Bacillus species. Further challenge studies with C. botulinum type E in sterile nuggets (i.e., in the absence of LAB and Bacillus spp.) showed that toxin was produced after 14 and 28 d in nuggets stored in air, and in air with an Ageless SS oxygen absorbent at 25 and 12$ sp circ$C, respectively. Further studies have now confirmed that Bacillus isolates, specifically B. subtilis, inhibited the growth of C. botulinum type E.

Thesis (Ph.D.)--University of Canterbury, 2007. / Typescript (photocopy). Includes bibliographical references. Also available via the World Wide Web.

Thesis (M. Phil.)--University of Hong Kong, 2008. / Also available in print.

Thesis (Ph.D.)--University of Tasmania, 2004. / For consultation only. No copying permitted until 13-3-2006. Includes bibliographical references.