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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Accelerated Shelf Life Determination of Antioxidant Stabilized High Oleic Sunflower and Canola Oils in Plastic Bottles

Shearer, Christine Nicole 11 November 2010 (has links) (PDF)
Vegetable oil is an important commodity; however, the majority of commercially available vegetable oils have a fairly short shelf life, which limits their usefulness for long term food storage, disaster relief, space travel, food aid programs, and military rations. Vegetable oils with high oleic acid and reduced linolenic acid contents, especially with added antioxidant combinations, were previously found to have significantly longer oil stability index (OSI) values than traditional vegetable oils. This study used accelerated shelf life testing to estimate the ambient shelf life of high oleic sunflower oil (HOSUN) and high oleic canola oil (HOCAN), each containing 1,000 ppm ascorbyl palmitate, 200 ppm tertiary butyl hydroquinone, and 200 ppm mixed tocopherols. Oils were stored in the dark in low density polyethylene (LDPE), or polyethylene terephthalate (PET) bottles at 30, 40, 50, and 60°C. Control samples were stored in the dark in glass bottles at -50°C. Testing included peroxide values, qualitative headspace volatile analysis, descriptive sensory analysis, and consumer sensory acceptance. The estimated shelf life was calculated from the change in overall acceptance score over time using the Q10 method. The stabilized HOCAN in PET bottles was estimated to have a shelf life at ambient temperature of 6.8 years, while oil stored in LDPE bottles had an estimated shelf life of only 2.7 years. The estimated shelf life of HOSUN at room temperature in PET is 2.6 years and in LDPE is 0.88 years.
2

Estudo de segurança e eficácia in vitro do ácido p-Cumárico e sua incorporação em emulsão cosmética óleo em água (O/A) /

Ramos, Wagner Soares January 2019 (has links)
Orientador: Marcos Antonio Correa / Resumo: O ácido p-cumárico (APC) é um composto fenólico não flavonóide que apresenta segurança e eficácia bem descritas na ciência dos alimentos devido suas propriedades antioxidante, antitumoral, anti-inflamatória, antimicrobiana e por apresentar baixa toxicidade oral. Essas propriedades são pouco exploradas em produtos para cuidados com a pele. O objetivo do presente estudo foi avaliar de forma in vitro a segurança e a eficácia do APC e incorporá-lo em emulsão cosmética óleo em água (O/A). Nossos estudos in vitro e alternativos ao uso de animais foram conduzidos para verificar a citotoxicidade do APC em células de queratinócitos (HaCat) e fibroblastos humanos (HDFa), o potencial de irritação ocular (HET-CAM) e a atividade antimicrobiana em diferentes cepas. Emulsões contendo APC foram submetidas ao estudo de estabilidade e de liberação, retenção e permeação cutâneas. Resultados: o IC50 do APC em células HaCat e HDFa foi 693,57 e 2.814,75 μg/mL, respectivamente. Além disso 100 μg de APC foram levemente tóxicos em membrana corioalantóica de ovo embrionado. As concentrações bactericidas mínimas em cepas de E. coli, S. aureus, P. aeruginosa e S. epidermidis, foram 3.000 μg/mL, 1.875 μg/mL, 3.750 μg/mL e 3.750 μg/mL, respectivamente. Emulsões contendo diferentes concentrações de APC foram estáveis durante o período de estabilidade acelerada. Após 12 horas 91,08 ± 0,03% do APC foi liberado da formulação e após 24 horas, 0,52 ± 0,18% e 0,94 ± 0,37% ficaram retidos no estrato córneo e na e... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: p-Coumaric acid (PCA) is a non flavonoid phenolic compound whose safety and efficacy widely described in food science papers due to antioxidant, antitumor, anti inflammatory properties, and low oral toxicity. These characteristics are poorly or no described when PCA is added to skin care products. The aim of the present study was to evaluate the safety and efficacy of PCA through in vitro assays, and then add it in oil in water cosmetic emulsion (O/W). Our in vitro trials, without animal use were conducted to predict PCA´s cytotoxicity in HaCat and HDFa cells, ophthalmic irritation potential, and antibacterial activity against differents strains. Emulsions with PCA has been tested to predict shelf life, dermal absorption, and dermal retention. Results: PCA´s IC50 in HaCat and HDFa cells was 693.57 and 2,814.75 μg.mL-1, respectively. In addition 100 μg of APC were slightly toxic in chorioallantoic membrane assay. The minimum bactericidal concentrations against E. coli, S. aureus, P. aeruginosa and S. epidermidis strains were 3,000 μg.mL-1, 1,875 μg.mL-1, 3,750 μg.mL-1, and 3,750 μg.mL-1 , respectively. Emulsions containing 0.04%, 0.06%, 0.08% and 0.10% of PCA were stable during self life testing for ninety days. After 12 hours 91.08 ± 0.03% of PCA was released of the emultion, and after 24 hours 0.52 ± 0.18% and 0.94 ± 0.37%, were present in stratum corneum and epidermis/dermis, respectively. Our findings indicate that PCA concentrations would be effective and safe to use in c... (Complete abstract click electronic access below) / Mestre

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