Thesis (Ph. D.)--University of Tennessee, Knoxville, 2002. / Title from title page screen (viewed Oct. 8, 2002). Thesis advisor: Matthew N. Murray. Document formatted into pages (x, 158 p. : ill. (some col.)). Vita. Includes bibliographical references (p. 151-157).

Thesis (Ph. D.)--University of Texas at Austin, 2007. / Vita. Includes bibliographical references.

Widespread consumption of canned tuna fish since the 1950s may explain some of the increase in breast cancer prevalence in the United States and Europe. Although canned tuna is the primary source of human exposure to methylmercury, its role as an estrogen activating metalloestrogen has been overlooked in the etiology and incidence of breast cancer. Carcinogenic theory asserts that increased exposure to estrogen elevates the risk of breast cancer. The purpose of this population-based, case control study was to examine the association between canned tuna consumption, total blood mercury, and breast cancer in the NHANES 2003-2006 surveys. A multivariable logistic regression model representing 138,747,398 U.S. adult females, controlling for covariates, was applied to investigate whether canned tuna consumption or blood mercury level had a relationship to breast cancer. According to study results, women who reported eating canned tuna at one level of increased frequency out of 11 had a 6.8% increased odds of being diagnosed with breast cancer (p =0. 000 OR 1.068 and 95% CI 1.067-1.069). Women with only a 0.01 Ug/L increase in total blood mercury level were found to have a 0.2% increased odds of being diagnosed with breast cancer (p =. 000 OR 1.002 and 95% CI 1.002-1.003). Additional research individuating the canned tuna fish variable in nutrition, fish, mercury, and breast cancer studies is recommended. This research contributes to positive social change by providing evidence to improve understanding and specification of canned tuna fish in future research and better identification of methylmercury levels in canned tuna fish for public knowledge.

CNPq / Brazil presents an important commercial fishing pole, which turns it to become relevant considering the benefits that consumption of fish plays in human nutrition. Canned fish promotes long shelf life of these food. However, foods that are rich sources of polyunsaturated fatty acids and cholesterol, such as tuna, have a great susceptibility for lipid oxidation when exposed to thermal processing. Cholesterol oxidation products (COP?s) are related to several diseases such as atherosclerosis, and can be absorbed from the diet. Thus, this study aimed to evaluate the lipid composition and COP?s production in canned tuna purchased from metropolitan area of Rio de Janeiro. Three trademarks of ?grated in brine? and ?in oil? canned tuna were evaluated. To determinate lipid oxidation, the fatty acid composition from the methyl esters of the fish and their brine were identified using gas chromatography with flame ionisation detector; cholesterol and cholesterol oxides were determined simultaneously, using high-performance liquid chromatography and confirmed by liquid chromatograph mass spectrometer (chemical ionization interface for atmospheric pressure) (APCI-MS). Tuna in ?brine? samples presented moisture contents in a range of 24.60 to 27.23g/100g; lipids contents ranging from 4.21 to 5.59g/100g; polyunsaturated fatty acids (PUFA) levels between 9.13 to 16,20g/100g, and high saturated fatty acids (SFA) contents (in a range of 54.66 to 59.85g/100g) (dry basis-DB). The nutritional quality index showed that lipid fractions presented undesirable values. These samples presented cholesterol concentration ranging from 190.95 to 399.28mg/100g, and high cholesterol oxidation products contents (between 321.42 and 414.94?g/100g- DB). Samples of ?in oil? canned tuna presented moisture and lipids contents of 31.93 to 51.33g/100g and 23.70 to 43.99g/100g, respectively; high polyunsaturated fatty acids concentration (46.06 to 49.92g/100g), especially the w6 series; and low levels of EPA and DHA amounts (in a range of 0.59 and 1.73g/100g). Cholesterol and COP?s contents varied from 135.90 to 191.92mg/100g and from 110.97 to 207.19?g/100g, respectively. Significate concentrations of cholesterol were identified in brine (18.99 to 37.10mg/100g) and ?in oil? samples (113.09 to 259.12mg/100g), and high COP?s contents were found (in a range of 230.54 and 477.12?g/100g from brine and 44.15 to 151.18?g/100g from ?in oil? samples). It was observed that there is a transference of lipids from fish to brine, as well as migration between fish lipids and vegetable oils in the ?oil? covers, changing the fatty acids profiles of both. It is considered that the production of canned fish contributes to loss of lipid quality, promotes fatty acids oxidation and induces the formation of cholesterol oxidation products. These results indicate that is necessary to conduct further studies to evaluate the occurrence of these undesirable compounds in fish products. / O Brasil possui um importante polo de pesca comercial, fato que se torna relevante considerando os benef?cios que o consumo de pescados desempenha na nutri??o humana. As conservas de peixes promovem nestes alimentos tempos de vida ?til prolongados. Entretanto, os alimentos ricos em ?cidos graxos poliinsaturados e colesterol, como os atuns, quando submetidos ao processamento t?rmico, apresentam grande potencial para a oxida??o lip?dica. Os produtos da oxida??o do colesterol (POC?s) est?o envolvidos no desenvolvimento de doen?as, como a aterosclerose, e podem ser absorvidos a partir da dieta. Desta forma, este trabalho teve como objetivos avaliar a composi??o lip?dica e a forma??o dos POC?s em conservas de atuns comercializadas na regi?o metropolitana do Rio de Janeiro. Foram avaliadas amostras de conservas ?raladas? em ?salmoura? e em ??leo? de 3 marcas comerciais. Para determina??o da oxida??o lip?dica, identificou-se a composi??o de ?cidos graxos dos atuns e respectivos l?quidos de coberturas a partir dos ?steres met?licos, atrav?s de Cromatografia Gasosa com detector de ioniza??o por chama; al?m da quantifica??o simult?nea do colesterol e dos POC?s, atrav?s de cromatografia l?quida de alta efici?ncia e confirmados por cromat?grafo l?quido com espetr?metro de massas (interface de ioniza??o qu?mica por press?o atmosf?rica) (APCI-MS). Os atuns em ?salmoura? apresentaram m?dias entre 24,60 a 27,23g/100g de umidade; entre 4,21 a 5,59g/100g de lip?deos; teores de 9,13 a 16,20g/100g de ?cidos graxos poliinsaturados (AGPI), e elevadas concentra??es de ?cidos graxos saturados (AGS) (entre 54,66 a 59,85g/100g), em base seca (BS). Foram evidenciados nos ?ndices de qualidade nutricional das fra??es lip?dicas com valores pouco desej?veis sob o ponto de vista nutricional. As concentra??es de colesterol nessas amostras variaram entre 190,95 a 399,28mg/100g, e foram identificados elevados teores de produtos de oxida??o do colesterol (entre 321,42 e 414,94?g/g/100g), em BS. As amostras de atuns em conservas contendo ??leo? apresentaram teores entre 31,93 e 51,33g/100g de umidade; entre 23,70 e 43,99g/100g de lip?deos, elevadas concentra??es de ?cidos graxos poliinsaturados (de 46,06 a 49,92g/100g), em especial os da s?rie w6 e reduzidos teores na soma de EPA e DHA (entre 0,59 e 1,73g/100g). As concentra??es de colesterol variaram entre 135,90 e 191,92mg/100g e os POC?s de 110,97 a 207,19?g/100g. Em rela??o aos l?quidos de coberturas, foram identificadas concentra??es significativas de colesterol (de 18,99 a 37,10mg/100g nas salmouras e de 113,09 a 259,12mg/100g nos ?leos, respectivamente), al?m de elevados teores de produtos de oxida??o do colesterol (entre 230,54 e 477,12?g/100g nas salmouras e entre 44,15 e 151,18?g/100g nos ?leos). Observou-se a transfer?ncia de lip?deos dos pescados para os l?quidos em ?salmoura?, al?m da migra??o de lip?deos entre os pescados e os ?leos vegetais nas conservas em ??leo?, alterando os perfis de ?cidos graxos de ambos os meios. Considera-se que a produ??o de conservas de peixes favorece a perda da sua qualidade lip?dica, promovem oxida??o de ?cidos graxos e induzem a forma??o de produtos de oxida??o do colesterol, fato que indica a necessidade da condu??o de novos estudos que avaliem a ocorr?ncia desses compostos indesej?veis oriundos da oxida??o lip?dica em produtos de pescados.

This dissertation is an empirical study of demand and supply in differentiated products markets using supermarket scanner data on two particular product categories - canned tuna and hot-breakfast cereals. First, I study the impact of retailers' price promotions on consumer demand and retailer profits in the canned-tuna product category. Since canned tuna is storable, I examine whether consumers stock up during sales. The results suggest that only a limited amount of stockpiling exists in this product category. Since inventory is not very important, consumer demand is thus modeled by a static demand model with a random-coefficients-nested-logit specification, which is estimated by the Markov Chain Monte Carlo method. The unit-sales decomposition results show that on average 36% of the demand response to price promotions comes from brand-switching, so market expansion effects due to consumers switching from the outside good and to higher quantities usually dominate the brand-switching effect. Using the demand estimates, I compute optimal retail prices assuming that stores are local monopolists and choose prices to maximize static category-level profits. I find that regular prices at "high-low" stores are typically at or slightly below the optimal prices, but that regular prices at "every-day-low-price" stores are substantially below the optimal prices. These results suggest that retail price levels and price promotions are more likely related to local market conditions such as retail competition. In addition, I study the effects of store-brand (SB) entry on the demand elasticities of incumbent national brands (NB), consumers' substitution patterns for national and store brands, and the implications for consumer welfare in the hot-breakfast-cereals product category. A random-coefficients model of consumer demand is estimated by the generalized-method-of-moments approach. The empirical findings are: (1) After the entry of SB's, demand becomes more elastic for non-imitated NB's, and either more elastic or shows no change for imitated NB's; (2) in general, substitution patterns for NB's and SB's are asymmetric, i.e., when the prices of their favorite products increase, most NB buyers tend to substitute to other NB products, but SB buyers will substitute to the corresponding imitated NB's; (3) the increase in consumer surplus due to SB entry is trivial for an individual consumer, but the aggregate benefit could be quite substantial.