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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

Genetic Pathways Involved in Response to the Phenol-Based Compounds Bisphenol-A (BPA) and Butylated Hydroxyanisole (BHA) in Saccharomyces Cerevisiae

Pecora, Camilla 17 May 2014 (has links)
Phenolic compounds exist in abundance in the world around us due to natural and synthetic biological processes. Phenols produced from chemical, petrol, and pharmaceutical processes can be harmful, stress-inducing exotoxins. Bisphenol-A (BPA) and butylated hydroxyanisole (BHA) are phenol-based compounds found in polycarbonate plastics and food preservatives, therefore presenting a particularly high degree of human exposure. Exposure to these compounds has been associated with numerous diseases, yet their mechanisms of action are not well understood. A quantitative evaluation of growth of yeast deletion strains was used to identify the genes that modulate response to phenol stress induced by BPA and BHA in the model organism, yeast Saccharomyces cerevisiae. Twelve genes were identified as essential for growth in the presence of both BPA and BHA. pep5 and vph2 are integral to vacuolar ATPase function, erg2 and erg24 are involved in the erg pathway, and ref2, rsc1, bdf1, tps2, hpr1, and snf12 are important in chromatin remodeling and transcription processes. Additional genes required for growth and growth-inhibiting genes were identified that were specific to BPA or BHA. Many of the genes identified in S. cerevisiae have orthologs in humans that may modulate exposure to toxic phenols in a similar manner and could provide insight into the pathways involved in phenol exposure related disease.
2

Avaliação da capacidade antioxidante de extratos comerciais de alecrim e chá verde e sua influência na estabilidade de hambúrguer de frango durante armazenamento congelado / Antioxidant activity evaluation of commercial extracts of rosemary and green tea and its influence on the stability of chicken burger during frozen storage

Pires, Manoela Alves 10 March 2014 (has links)
A atividade antioxidante de dois extratos comerciais de alecrim e chá verde foi comparada com a atividade do sintético BHA para substituição total do sintético em hambúrguer de frango. A quantificação foi determinada pelos métodos Folin-Ciocalteau, FRAP e DPPH. De acordo com as análises de atividade antioxidante, as dosagens dos extratos naturais foram determinadas, utilizando-se como base o limite de dosagem do BHA (0,01% base gordura) e aplicadas em hambúrgueres de frango: T1: Controle; T2: 0,002% BHA; T3: 0,0038% Chá Verde; T4: 0,001% Chá Verde; T5: 0,048% Alecrim; T6: 0,00186% Alecrim. Foram realizadas análises de composição centesimal e pH e análises de estabilidade no armazenamento congelado: rendimento e redução do diâmetro, índice de TBARs, cor objetiva (parâmetros L*, a* e b*) e teste sensorial de aceitação. No método Folin-Ciocalteau, das análises de atividade antioxidante, o BHA não apresentou diferença com o chá verde (p > 0,05), no método FRAP o melhor (p < 0,05) desempenho foi do BHA e no DPPH o chá verde apresentou maior atividade (p < 0,05). Os resultados de TBARS, nos hambúrgueres, mostraram diferença significativa entre as amostras e também interação amostras x tempo do armazenamento (p < 0,05), sendo que após 120 dias o teste com maior dosagem do extrato de alecrim (T5) não diferiu do sintético (T2) (0,423 e 0,369 índice de TBARs, respectivamente). No aspecto sensorial as amostras não diferiram entre si (p>0,05) nem durante todo o período de armazenamento (p > 0,05). Dentro das condições experimentais pode-se afirmar que o extrato comercial de alecrim pode substituir totalmente o antioxidante BHA em hambúrguer de frango, garantindo a mesma estabilidade oxidativa e sem interferir em sua aceitação sensorial. / The antioxidant activity of two commercial extracts, rosemary and green tea, were compared with the activity of the synthetic BHA for total replacement of the synthetic in chicken burger. The spectrometric quantification was determined by UV - VIS methods: Folin - Ciocalteu , FRAP and DPPH . In the Folin-Ciocalteau method the BHA showed no difference with green tea (p > 0.05), in the FRAP method the BHA obtained better (p < 0.05) performance and for DPPH the green tea showed greater activity (p < 0.05). According to the analysis of antioxidant activity, dosages of natural extracts were determined, using as basis the limit dosage of BHA (0.01 % fat base) and applied in chicken burgers: T1: Control, T2: 0.002 % BHA, T3: 0.0038 % Green Tea, T4: 0.001 % Green Tea, T5: 0.048 % Rosemary and T6: 0.00186 % Rosemary. Chemical-physical analysis of chemical composition and pH were made, and also stability analysis: cooking loss and reducing the diameter, TBARs index, objective color (parameters L *, a * and b *) and sensory acceptance test. The results of TBARS showed a significant difference between samples and also samples interaction x storage time (p < 0.05), after 120 days the test with higher dosage of rosemary extract (T5) did not differ from synthetic (T2) (0.423 and 0.369 TBARS index, respectively), thus better performance than the other tests. The sensory evaluation results showed that the samples did not differ during the storage period (p > 0.05). According the experimental conditions can be concluded that the commercial rosemary extract can completely replace the antioxidant BHA.
3

Compósitos de grafite a base poliuretana modificados com SBA-15 na determinação dos antioxidantes BHA e TBHQ em biodiesel / Polyurethane-based graphite composites modified with SBA-15 in the determination of antioxidants BHA and TBHQ in biodiesel

OLIVEIRA, Danielle Cristina Vasconcelos de 05 September 2017 (has links)
Submitted by Rosivalda Pereira (mrs.pereira@ufma.br) on 2017-10-06T16:33:36Z No. of bitstreams: 1 DanielleOliveira.pdf: 1130236 bytes, checksum: 83c34f9b54d583457ebfcfe859d26da1 (MD5) / Made available in DSpace on 2017-10-06T16:33:36Z (GMT). No. of bitstreams: 1 DanielleOliveira.pdf: 1130236 bytes, checksum: 83c34f9b54d583457ebfcfe859d26da1 (MD5) Previous issue date: 2017-09-05 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Conselho Nacional de Desenvolvimento Científico e Tecnológico / Fundação de Amparo à Pesquisa e ao Desenvolvimento Científico e Tecnológico do Maranhão / Due to the importance of the antioxidants to guarantee the quality of the biodiesel, by the parameters of its oxidative stability, analytical methodologies have been developed to quantitatively evaluate the antioxidants present in the biodiesel matrices. In this work SBA-15 and Ni- SBA-15 (nickel incorporated in the SBA-15) were synthesized by the hydrothermal method and characterized, being used as modifier (2.5%) in polyurethane graphite based electrochemical sensors to compare their Performance in determining the antioxidants BHA (3-tert-butyl-4-hydroxyanisole) and TBHQ (tert-butylhydroquinone). Among the sensors used, the GPU electrode modified with SBA-15 was the one that presented the best response in the determination of the antioxidants in the preliminary tests, being then applied in the determination of the antioxidants in the biodiesel sample, using the technique of Differential Pulse Voltammetry (DPV ), Using BR as buffer pH = 2 as the electrolyte. The proposed method presented a linear response in the antioxidant determinations (0.993, for TBHQ determinations and 0.977 for BHA determinations), good results for the limit of detection (LOD BHA = 1, (2.03 for determinations of TBHQ and 2.13 for determinations of BHA) and accuracy (102.5% for determinations of TBHQ and 98, 97% for BHA determinations). / Devido à importância dos antioxidantes para garantir a qualidade do biodiesel, pelos parâmetros de sua estabilidade oxidativa, metodologias analíticas têm sido desenvolvidas para avaliar quantitativamente os antioxidantes presentes nas matrizes de biodiesel. Neste trabalho, SBA-15 e Ni- SBA-15 (niquel incorporado na SBA-15) foram sintetizados pelo método hidrotermal e caracterizados, sendo utilizados como modificador (2,5%) em sensores eletroquímicos à base de grafite de poliuretano para comparar o seu desempenho na determinação dos antioxidantes BHA (3-terc-butil-4-hidroxianisol) e TBHQ (tercbutilhidroquinona). Dentre os sensores utilizados, o eléctrodo GPU modificado com SBA-15 foi o que apresentou a melhor resposta na determinação dos antioxidantes nos testes preliminares, sendo então aplicado na determinação dos antioxidantes na amostra de biodiesel, utilizando a técnica de Voltametria de Pulso Diferencial (DPV), usando como eletrólito suporte o tampão BR com pH = 2. O método proposto apresentou uma resposta linear nas determinações antioxidantes (0,993, para determinações TBHQ e 0,977 para determinações BHA), também apresentou bons resultados para o limite de detecção (LD BHA= 1,00 x 10 -5, LD TBHQ = 7, 76 X 10-6), Precisão (2,03 para determinações de TBHQ e 2,13 para determinações de BHA) e exatidão (102,5% para determinações de TBHQ e 98,97% para determinações de BHA).
4

Avaliação da capacidade antioxidante de extratos comerciais de alecrim e chá verde e sua influência na estabilidade de hambúrguer de frango durante armazenamento congelado / Antioxidant activity evaluation of commercial extracts of rosemary and green tea and its influence on the stability of chicken burger during frozen storage

Manoela Alves Pires 10 March 2014 (has links)
A atividade antioxidante de dois extratos comerciais de alecrim e chá verde foi comparada com a atividade do sintético BHA para substituição total do sintético em hambúrguer de frango. A quantificação foi determinada pelos métodos Folin-Ciocalteau, FRAP e DPPH. De acordo com as análises de atividade antioxidante, as dosagens dos extratos naturais foram determinadas, utilizando-se como base o limite de dosagem do BHA (0,01% base gordura) e aplicadas em hambúrgueres de frango: T1: Controle; T2: 0,002% BHA; T3: 0,0038% Chá Verde; T4: 0,001% Chá Verde; T5: 0,048% Alecrim; T6: 0,00186% Alecrim. Foram realizadas análises de composição centesimal e pH e análises de estabilidade no armazenamento congelado: rendimento e redução do diâmetro, índice de TBARs, cor objetiva (parâmetros L*, a* e b*) e teste sensorial de aceitação. No método Folin-Ciocalteau, das análises de atividade antioxidante, o BHA não apresentou diferença com o chá verde (p > 0,05), no método FRAP o melhor (p < 0,05) desempenho foi do BHA e no DPPH o chá verde apresentou maior atividade (p < 0,05). Os resultados de TBARS, nos hambúrgueres, mostraram diferença significativa entre as amostras e também interação amostras x tempo do armazenamento (p < 0,05), sendo que após 120 dias o teste com maior dosagem do extrato de alecrim (T5) não diferiu do sintético (T2) (0,423 e 0,369 índice de TBARs, respectivamente). No aspecto sensorial as amostras não diferiram entre si (p>0,05) nem durante todo o período de armazenamento (p > 0,05). Dentro das condições experimentais pode-se afirmar que o extrato comercial de alecrim pode substituir totalmente o antioxidante BHA em hambúrguer de frango, garantindo a mesma estabilidade oxidativa e sem interferir em sua aceitação sensorial. / The antioxidant activity of two commercial extracts, rosemary and green tea, were compared with the activity of the synthetic BHA for total replacement of the synthetic in chicken burger. The spectrometric quantification was determined by UV - VIS methods: Folin - Ciocalteu , FRAP and DPPH . In the Folin-Ciocalteau method the BHA showed no difference with green tea (p > 0.05), in the FRAP method the BHA obtained better (p < 0.05) performance and for DPPH the green tea showed greater activity (p < 0.05). According to the analysis of antioxidant activity, dosages of natural extracts were determined, using as basis the limit dosage of BHA (0.01 % fat base) and applied in chicken burgers: T1: Control, T2: 0.002 % BHA, T3: 0.0038 % Green Tea, T4: 0.001 % Green Tea, T5: 0.048 % Rosemary and T6: 0.00186 % Rosemary. Chemical-physical analysis of chemical composition and pH were made, and also stability analysis: cooking loss and reducing the diameter, TBARs index, objective color (parameters L *, a * and b *) and sensory acceptance test. The results of TBARS showed a significant difference between samples and also samples interaction x storage time (p < 0.05), after 120 days the test with higher dosage of rosemary extract (T5) did not differ from synthetic (T2) (0.423 and 0.369 TBARS index, respectively), thus better performance than the other tests. The sensory evaluation results showed that the samples did not differ during the storage period (p > 0.05). According the experimental conditions can be concluded that the commercial rosemary extract can completely replace the antioxidant BHA.
5

Design and Analysis of a Test Rig for Modeling the Bit/Formation Interface in Petroleum Drilling Applications

Wilson, Joshua Kyle 03 October 2013 (has links)
Equipment failure and well deviations are prevailing contributors to production delays within the petroleum industry. Particular monetary focus is given to the drilling operations of wells to overcome these deficits, in order to extract natural resources as efficiently, and as safely, as possible. The research presented here focuses on minimizing vibrations of the drill string near the bottom-hole assembly (BHA) by identifying the cause of external forcing on the drillstring in vertical and horizontal wells and measuring the effects of various factors on the stability of perturbations on the system. A test rig concept has been developed to accurately measure the interaction forces and torques between the bit, formation and fluids during drilling in order to clearly define a bit/formation interface law (BFIL) for the purpose vibrational analysis. As a secondary function, the rig will be able to measure the potential inputs to a drilling simulation code that can be used to model drillstring vibrations. All notable quantities will be measured including torque on bit (TOB), weight on bit (WOB), lateral impact loads (LIL), formation stiffness, bit specific properties, fluid damping coefficients and rate of penetration (ROP). The conceptual design has been analyzed and refined, in detail, to verify its operational integrity and range of measurement error. The operational envelope of the rig is such that a drill bit of up to 8 ½ inches in diameter can be effectively tested at desired operational parameters (WOB: 0-55,000 lbf, RPM: 60-200) with various rock formations and multiple fluid types. Future use and design possibilities are also discussed to enhance the functionality of the rig and the potential for further research in the area of oil and gas drilling and vibrational modeling.
6

Sledování těkavých látek v granulovaném krmivu pro psy / Monitoring of Volatile Compounds in Dry Dog Foods

Šímová, Lenka January 2016 (has links)
The aim of this study was to explore the influence of volatile compounds in dry dog food on its attractiveness for dogs. The assumption was that the attractiveness is mainly affected by volatile compounds presented in the feed. This study brings overall information about dog´s digestive system and its nutritional requirements with the summary of available feeds including the production process and list of the customary ingredients. A survey of the most common volatile compounds including appropriate analytical methods is also part of this study. A feed preference test was performed in experimental part of this study. The preference ratio of two dry dog diets was set to 21:79 % that shows clear preference for one of the feeds. Chemical analysis using gas chromatography-mass spectrometry revealed distinctions in the volatile compounds profile of the tested feeds. 3-tert-butyl-4-hydroxyanisole that is part of synthetic antioxidant BHA was identified to be the main volatile compound that could possibly be responsible for feed preferences observed in this study.
7

DESENVOLVIMENTO DE PROCEDIMENTOS ANALÍTICOS PARA DETERMINAÇÃO DE ANALITOS EM AMOSTRAS DE INTERESSE AMBIENTAL, ALIMENTÍCIO E FARMACÊUTICO UTILIZANDO ESPECTROFOTOMETRIA DERIVATIVA E ESPECTROFLUORIMETRIA / ANALYTICAL PROCEDURES FOR DEVELOPMENT DETERMINATION OF INTEREST ANALYTES IN SAMPLES ENVIRONMENT, FOOD AND PHARMACEUTICAL USING SPECTROPHOTOMETRY DERIVATIVE AND SPECTROFLUORIMETRY

Neiva, Ariane Maciel 27 February 2015 (has links)
Submitted by Cibele Nogueira (cibelenogueira@ufgd.edu.br) on 2016-04-13T14:53:03Z No. of bitstreams: 2 license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) ARIANENEIVA.pdf: 1246302 bytes, checksum: a9b98c41e97de74c859c345cfeec9d43 (MD5) / Made available in DSpace on 2016-04-13T14:53:03Z (GMT). No. of bitstreams: 2 license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) ARIANENEIVA.pdf: 1246302 bytes, checksum: a9b98c41e97de74c859c345cfeec9d43 (MD5) Previous issue date: 2015-02-27 / DEVELOPMENT OF ANALYTICAL PROCEDURES FOR DETERMINATION of analytes in SAMPLE ENVIRONMENTAL, FOOD AND PHARMACEUTICAL INTEREST USING SPECTROPHOTOMETRY DERIVATIVE AND SPECTROFLUORIMETRY. In this working is shown the development of three analytical procedures: The first procedure was based on the first-order derivative spectroscopy for the simultaneous determination of BHA, BHT without previous separation, using the zero-crossing technique in mayonnaise and salad dressing samples. The procedure showed a linear range varying between 5.55x10-5 to 3.33x10-4 mol L-1 for quantification of BHA. The linear range for BHT determination varying between 9.08x10-5 to 5.44x10-4 mol L-1. The detection limit and quantification limit obtained for the proposed procedure were 2.53x10-5 mol L-1 and 6.67x10-5 moles L-1, respectively for BHA, and 4.77x10-5 mol L-1 and 1.44x10-4 mol L-1, respectively for BHT. The second developed procedure employs spectrofluorimetry for determination of ketoconazole in different matrices (river water samples and tablets). The calibration curve showed linearity between 5.00x10-7 to 1.00x10-5 mol L-1, and a detection limit of 1.36x10-7 mol L-1. The recoveries ranging from 75.2 to 98.5% for drug samples and from 75.6 to 108% for river water samples were obatined. The third spectrofluorimetric procedure developed was based on the fluorescence of bisphenol-A. The procedure was developed to determine BFA in river water samples. The calibration curve obtained was linear between 7.50x10-7 to 1.00x10-5 mol L-1. the detection limit of 7.37x10-7 mol L-1 and recoveries ranging from 70.5 to 106% for river water samples were obtained. / DESENVOLVIMENTO DE PROCEDIMENTOS ANALÍTICOS PARA DETERMINAÇÃO DE ANALITOS EM AMOSTRAS DE INTERESSE AMBIENTAL, ALIMENTÍCIO E FARMACÊUTICO UTILIZANDO ESPECTROFOTOMETRIA DERIVATIVA E ESPECTROFLUORIMETRIA. Neste trabalhado é apresentado o desenvolvimento de três procedimentos analíticos: O primeiro procedimento emprega a espectroscopia derivativa de primeira ordem para a determinação simultânea de BHA-BHT sem a necessidade de separação prévia, utilizando a técnica zero crossing em amostras de maionese e molho de salada. Os procedimentos apresentaram faixa linear variando entre 5,55x10-5 a 3,33x10-4mol L-1 para quantificação de BHA e 9,08x10-5 a 5,44x10-4 mol L-1 para quantificação de BHT. O limite de detecção e quantificação calculados para o procedimento proposto foram de 2,53x10-5 mol L-1 e 6,67x10-5 mol L-1, respectivamente para BHA, 4,77x10-5 mol L-1 e 1,44x10-4 mol L-1 respectivamente para BHT. O segundo procedimento emprega a espectrofluorimetria para determinação de Cetoconazol em duas matrizes (amostras de água de rio e comprimidos). A curva analítica apresentou uma linearidade entre 5,00x10-7 a 1,00x10-5 mol L-1 e umlimite de detecção de 1,36x10-7 mol L-1. As recuperações que variaram de 75,2 a 98,5% para as amostras farmacêuticas e 75,6 a 108% para amostras de água de rio. O terceiro procedimento apresenta o emprego da espectrofluorimetria para determinação de bisfenol-A em amostras de água de rio. A curva analítica apresentou uma linearidade entre 7,50x10-7 a 1,00x10-5 mol L-1 e um limite de detecção de 7,37x10-7 mol L-1, com recuperações que variaram de 70,5 a 106% para as amostras de água de rio.
8

Vibration Suppression and Flywheel Energy Storage in a Drillstring Bottom-Hole-Assembly

Saeed, Ahmed 2012 May 1900 (has links)
In this study, a novel concept for a downhole flywheel energy storage module to be embedded in a bottom-hole-assembly (BHA) is presented and modeled, as an alternative power source to existing lithium-ion battery packs currently deployed in measurement-while-drilling (MWD) or logging-while-drilling (LWD) operations. Lithium-ion batteries disadvantages include deteriorated performance in high temperature, limited lifetime that necessitates frequent replacement which elevates operational costs, and environmental disposal. Extreme and harsh downhole conditions necessitate that the flywheel module withstands temperatures and pressures exceeding 300 ?F and 20 kpsi, respectively, as well as violent vibrations encountered during drilling. Moreover, the flywheel module should adhere to the geometric constraints of the wellbore and its corresponding BHA. Hence, a flywheel sizing procedure was developed that takes into consideration the required energy to be stored, the surrounding environmental conditions, and the geometric constraints. A five-axis magnetic levitation control system was implemented and tuned to maintain continuous suspension of the flywheel under the harsh lateral, axial and torsional drilling vibrations of the BHA. Thus, an integrated finite element model was developed that included the rotordynamic behavior of the flywheel and the BHA, the component dynamics of the magnetic levitation control system, and the cutting dynamics of the drillbit for both PDC and tricone types. The model also included a newly developed coupling between lateral, axial and torsional vibrations. It was demonstrated through simulations conducted by numerical integration that the flywheel maintains levitation due to all different types of external vibration as well as its own lateral vibration due to mass unbalance. Moreover, a passive proof-mass-damper (PPMD) was developed that suppresses axial bit-bounce vibrations as well as torsional vibrations, and was extended to also mitigate lateral vibrations. Optimized values of the mass, stiffness and damping values of the PPMD were obtained by the hybrid analytical-numerical Chebyshev spectral method that was superior in computational efficiency to iterative numerical integration. This also enabled the fine-plotting of an operating stability chart indicating stability regions where bit-bounce and stick-slip are avoided. The proof-mass-damping concept was extended to the flywheel to be an active proof-mass-damper (APMD) where simulations indicated functionality for a light-weight BHA.
9

Changes in Cell Morphology and the Cellular Localization of Protein Kinase Dsk1 in Schizosaccharomyces pombe in Response to Butylated Hydroxyanisole

Humphries, Jacqueline T 01 January 2013 (has links)
Dsk1 is the Schizosaccharomyces pombe functional homolog of human SRPK1, an SR protein kinase that regulates localization and function of SR protein splicing factors involved in transcription, alternative splicing, and mRNA export. It has been shown that a Dsk1 deletion strain of S. pombe is sensitive to exposure to butylated hydroxyanisole (BHA), a phenol derivative commonly used as a food preservative. Little is known about how BHA interacts with cells on a functional level, although it has been shown to be cytotoxic and tumorigenic. The aims of this thesis are to study the effect of BHA on eukaryotic cells and the possible involvement of Dsk1 protein kinase in the cellular response network to BHA through the use of fluorescence microscopy. The results showed that in BHA-treated cells, Dsk1 exhibits reduced nuclear localization and increased incidence of cytoplasmic clusters as well as a series of changes in cellular morphology. These observations imply that the function of Dsk1 is altered in response to BHA, consistent with genomic data collected by the Tang Lab. Thus, this study provides a basis for a series of future studies that will reveal in more detail how BHA affects fission yeast cells, and potentially gene or protein functional homologs in human cells.
10

Influência do processamento, de antioxidantes e da estocagem sobre a estabilidade oxidativa lipídica do ovo / Influence of processing, antioxidants and storage on oxidative stability of egg lipids

Carvalho, Michelle Garcêz de 01 November 2012 (has links)
O ovo é consumido in natura ou processado, e usado como matéria-prima em diversos produtos. A pasteurização e a atomização são os principais processamentos aplicados ao ovo. Diferentes condições de processamento, embalagem e estocagem podem afetar a estabilidade oxidativa lipídica e reduzir a proteção antioxidante natural do ovo. O uso de embalagens onde não haja contato do ovo com a luz e oxigênio, estocagem em temperaturas baixas e uso de antioxidantes podem prevenir a oxidação lipídica. Atualmente, os antioxidantes sintéticos são cada vez mais substituídos por antioxidantes naturais ou feita uma associação entre eles. O alecrim (Rosmarinus officinalis L.) e o chá verde (Camelia sinensis L) constam entre os vegetais com grande potencial antioxidante. Com base no exposto, os objetivos do trabalho foram: a) Padronizar o método do fosfomolibdênio para avaliação da capacidade antioxidante total da fração lipídica (CATL) do ovo; b) Investigar o efeito da pasteurização e da atomização do ovo no que se refere à capacidade antioxidante e à estabilidade oxidativa da fração lipídica do ovo; c) Avaliar a estabilidade oxidativa de ácidos graxos e a capacidade antioxidante do ovo integral pasteurizado atomizado, estocado a 5ºC, por 90 dias; d) Verificar por meio de teste de concentração de antioxidantes, a estabilidade oxidativa lipídica do ovo integral pasteurizado atomizado adicionado da mistura de extrato de alecrim, extrato de chá verde e BHA (butilato de hidroxianisol); e) Otimizar a concentração da mistura de extrato de alecrim, extrato de chá verde e BHA a ser adicionada ao ovo líquido integral pasteurizado, posteriormente atomizado, pelo modelo matemático proposto pela metodologia de superfície de resposta; f) Investigar o efeito da mistura otimizada de extrato de alecrim, extrato de chá verde e BHA na estabilidade oxidativa lipídica do ovo integral pasteurizado atomizado, estocado sob as temperaturas de 5°C e 25ºC, por 90 dias. O método do fosfomolidênio para medir a CATL do ovo apresentou adequação analítica, indicada pela equação de regressão (y = 13,705x + 0,0808), coeficiente de determinação (R2 = 0,9931), limite de detecção (0,005mg α-tocoferol/ mL), limite de quantificação (0,017mg α-tocoferol/ mL), coeficiente de correlação (r = 0,9965), sendo que a precisão não indicou dispersão ao redor da média. A CATL diminuiu com o progresso do processamento e o inverso foi observado quanto aos lipídios, 7-CETO (7-cetocolesterol) e TBARS (substâncias reativas ao ácido tiobarbitúrico). O ovo integral pasteurizado atomizado (OIPA) mantido sob condições de estocagem consideradas ideais permaneceu estável em relação à hidratação, a CATL e as TBARS. Pelo teste de concentração de antioxidantes, foram ensaiadas dez misturas (alecrim, chá verde e BHA) no OIPA e refletiu na sua estabilidade oxidativa lipídica, verificada pelas TBARS, CATL, CT-F (capacidade redutora pelo reativo de Folin - Ciocalteau), AGL (ácidos graxos livres) e AS-233 (substâncias absorvidas a 233 nm). Os resultados mostraram que a metodologia de superfície de resposta (RSM) foi adequada para descrever a formação dos AGL e AS-233 no OIPA, podendo serem usadas para fins preditivos. A otimização da mistura de antioxidantes baseou-se no modelo matemático obtido com as AS-233, onde foi proposto como sistema antioxidante 150ppm de BHA, 600ppm de alecrim e 300ppm de chá verde. As condições de estocagem adotadas e a adição dos antioxidantes foram efetivas para manter estável o OIPA, sendo mais efetivo quando estocado a 5°C. Concluíu-se que o método do fosfomolibdênio apresentou adequação analítica. A pasteurização não afetou os parâmetros analisados (lipídios, TBARS, CATL e 7-CETO), mas a atomização provocou diminuição significativa da CATL, e elevação dos lipídios, TBARS e 7-CETO. Foi mantida a hidratação e a estabilidade oxidativa do OIPA estocado por 90 dias a 5°C, indicando que as condições de embalagem e estocagem foram efetivas. Pelo modelo matemático proposto pela RSM foi constatado que apenas os AGL e AS-233 podem ser usados para fins preditivos, optando-se pela otimização da concentração da mistura de antioxidantes, usando apenas o modelo matemático obtido nas AS-233. Com a presença ou não de antioxidantes, o OIPA estocado a 5°C, ao longo dos 90 dias, apresentou-se mais estável quanto à hidratação e à oxidação lipídica. / Egg is consumed in natura or processed and is used as raw material in various food products. The pasteurization and spray-drying processes are the main processing applied to the egg. Different processing conditions, packaging and storage can affect the lipid oxidative stability and may reduce the natural antioxidant protection of this product. The use of packages in which the egg has no contact with light and oxygen, storage at low temperatures, and the use of antioxidants can prevent lipid oxidation. Currently, synthetic antioxidants have been increasingly replaced by natural antioxidants or an association between synthetic and natural antioxidants is adopted by food companies. Rosemary (Rosmarinus officinalis L.) and green tea (Camellia sinensis L) are among the vegetables that present the highest antioxidant potential. Based on the above-mentioned considerations, the objectives of this research were: a) To standardize the method of phosphomolybdenum to evaluate the total antioxidant capacity of lipid fraction (CATL) egg; b)To investigate the effect of pasteurization and spray-drying on the antioxidant capacity and oxidative stability of the lipid fraction of egg; c) To assess the oxidative stability of fatty acids and the antioxidant capacity of whole egg subjected to pasteurization followed by spray-drying, stored at 5ºC for 90 days, d) To evaluate the by testing the concentration of antioxidants, oxidative stability of the lipid fraction of egg subjected to pasteurization and spray drying, added with a mixture of rosemary and green tea extracts and BHA (butylated hydroxyanisole); e) To optimize the concentration of the mixture composed of rosemary and green tea extracts and BHA to be added to pasteurized liquid egg (and further subjected to spray-drying) by using Response Surface Methodology; f) To investigate the effect of the addition of this optimized mixture of antioxidants on of the lipid fraction of spray-dried egg, stored at temperatures of 5 and 25°C for 90 days. The phosphomolybdenum method CATL of egg presented analytical suitability once it presented a high coefficient of determination (R2 = 0,9931), a regression equation expressed as y = 13.705 + 0.0808 x, a limit of detection of 0.005 mg α- tocopherol/mL, a limit of quantitation of 0.017 mg α-tocopherol/mL, a significant and high correlation coefficient (r = 0.9965), and the accuracy did not indicate dispersion around the mean. The CATL decreased with the progress of processing and the reverse was observed for the lipids, 7-CETO (7-ketocholesterol) and TBARS (thiobarbituric acid reactive substances). The pasteurized spray-dried egg (OIPA), which was kept under ideal storage conditions, remained stable in relation to moisture content, CATL and TBARS. In order to test the concentration of antioxidants to be added to OIPA, a total of 10 mixtures (rosemary, green tea and BHA) were assayed. The addition of antioxidants resulted in a higher oxidative stability of the lipid fraction as measured by TBARS, CATL, CT-F (reduction capacity by using the Folin-Ciocalteau reagent), AGL (free fat acids) and AS-233 (substances that absorb at 233 nm). The results showed that the response surface methodology (RSM) was adequate to describe the development of free fat acids and AS-233 in OIPA, and the RSM model proposed for AS-233 can be used for prediction purposes. The optimization of the antioxidant mixture based on the mathematical model proposed for AS-233 indicated that the mixture of 150ppm of BHA, 600ppm of rosemary extract and 300ppm of green tea extract was the best combination of antioxidants. The adopted storage conditions and the addition of antioxidants to OIPA were effective to maintain the response variables stable, and the stability was higher when OIPA was stored at 5°C. It was concluded that the method of phosphomolybdenum suitability presented analytically. The pasteurization did not affect the analyzed parameters (lipids, TBARS, CATL and 7-CETO), but the spray-drying caused a significant decrease CATL, and an increase in lipids, TBARS and 7-CETO. The hydration and the oxidative stability of OIPA remained stable for 90 days at 5°C, indicating that the packaging and storage conditions were effective. The RSM models proposed for free fat acids and AS-233 could be used for predictive purposes; however, the optimization procedure was performed taken into account only the AS-233 model. The OIPA stored at 5°C for 90 days, with or without the addition of the antioxidant mixture, was more stable in relation to hydration and lipid oxidation.

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