The aim of the diploma thesis was determined the particular fatty characteristics of various vegetable oils in dependence on their storage life and storage conditions. Storage conditions were defined by room temperature and coolroom temperature. The fourteen oils were used for analyses, namely linseed oils, castor oil, grape seed oil, almond oil, olive oil, jojoba oil, avocado oil, apricot kernel oil, corn oil, rice bran oil, macadamia nut oil, soya bean oil, pumpkin seed oil and sunflower oil. All tested oils were supplied by firm M+H, Míča a Harašta s.r.o. The fatty characteristics included the saponification value, the acid value, the iodine value and the thiobarbituric value. The ester values and the percentage glycerol content were counted on the basis of the saponification value and the acid value. Time dependences of all fatty characteristics were figured to graphs and they were compared on various storage conditions. The fatty characteristics indicated lower values in storage of oil samples in coolroom than at laboratory temperature.

The aim of the diploma thesis was the identification of fatty acids contained in vegetable oils by gas chromatography. Amount of fatty acids was monitored in dependence on the duration and conditions of storage. Conditions for storage were selected at room temperature and refrigerator temperature. In total fourteen oils were analyzed - avocado oil, pumpkin seed oil, grape seed oil, jojoba oil, corn oil, linseed oil, macadamia oil, almond oil, apricot-stone oil, olive oil, castor oil, rice oil, sunflower oil and soya bean oil. Gas chromatography was applied for identification and quantification of fatty acids. Methanol esterification method using potassium hydroxide catalysis was chosen for preparing of the samples of the fatty acid methylesters. Eight fatty acids were observed in the vegetable oils : myristic, palmitic, palmitoleic, stearic, oleic, linoleic, gama-linolenic and linolenic acids.

M. Tech. (Department of Chemistry, Faculty of Applied And Computer Sciences), Vaal University of Technology. / Biodiesel has an ability to solve the problem associated with the use of fossil fuels as a source of energy. The aim of this study was to produce biodiesel from waste cooking oil (WCO) by transesterification, catalysed with potassium hydroxide (KOH) supported on attapulgite (ATP) clay as the heterogeneous catalyst. WCO was used on the basis that it is one of the cheapest feedstocks for biodiesel production, is readily available and can minimise environmental impact. ATP clay was first crushed and sieved to particle sizes of ≤ 90 μm and subsequently treated with hydrochloric acid (HCl) to remove impurities. The KOH supported ATP catalyst was prepared through ion exchange method by soaking ATP into KOH solution, dried in an oven and later calcined at 400 ℃ in a furnace. The prepared catalyst and ATP clay were characterised using Hammett indicator to determine the basic strength of the catalyst. XRF and EDX were used to determine the elemental composition of the catalyst whilst XRD was used to determine the crystallinity of the ATP after modification. The functional groups of ATP were determined by FTIR. BET was utilised to determine the changes on the surface area, pore volume and pore diameter of ATP and on the other hand, SEM was used to determine the morphological changes on the surface of ATP. The XRD, FTIR, BET AND SEM-EDX showed that addition of potassium caused changes on the surface of the ATP. The optimal conditions for the transesterification reaction of waste cooking oil with methanol were found to be oil-to-methanol molar ratio of 1:15, 3wt% catalyst amount, 65 ℃, 3 h of a reaction time, at 200 rpm stirring rate and 94 % biodiesel yield was obtained. After the catalyst was reuse three consecutive times, the decrease in biodiesel yield was observed (Figure 17) after each cycle. However, the 5MKOH/ATP catalyst is heterogeneous and can be used to transesterify WCO with good yield.

Thesis submitted in 50 % completion of the degree of Master of Management in the field of Public and Development Management at the University of the Witwatersrand, Johannesburg. 20 June 2016 / In response to the ever increasing problems associated with climate change, and greenhouse gas emissions, many countries in the world are developing and adopting climate change resilient policies that support green economy. Green economy sector in South Africa has not as yet received much expected attention as a key sector to address economic and environmental problems. The use and the production of renewable fuels, such as biodiesel are known to have significant economic and environmental benefits. However, progress in the production of biodiesel is hampered by limits imposed by government on the use of fresh vegetable extracted oils for production of biodiesel, mainly due to challenges on food security; and the impact this will have on food prices. In recent years recycling has become an important tool to address waste problems; pollution control; and socio-economic problems such as joblessness, poverty and social inequity. Used cooking oil has always been considered waste and an environmental burden. Therefore through technology advancement of recycling, wastes such as used cooking oil have become useful resources for biodiesel production. This research is about the challenges in recycling used cooking oil to produce biodiesel. The study recommended that in order to address challenges facing sustainability of our environment, and high unemployment rate; small recycling industries such as those operating in Polokwane will need government support such as biodiesel sector policies and regulations, to encourage investment in the biodiesel value chains in a way that will lead to the achievement of green economy goals. / MT2016

No / Biodiesel has turned out to be an integral part of the discussion of renewable energy sources and has diverse advantages in terms of its flexibility and applicability. Considering the characteristics of the transesterification reaction, a laboratory-scale system has been developed in this work. Waste Vegetable Oil (WVO), mainly sunflower oil, from local sources has been used and the transesterification carried out using methanol in the presence of sodium hydroxide catalyst. Characterisation of the biodiesel produced has been carried out using a number of different techniques including rheology, calorimetry, and gas liquid chromatography. The main factors affecting the % yield of biodiesel are temperature, catalyst, and alcohol to triglyceride ratio. Thus, experimental work has been carried out so as to study the rate and yield of the reaction as a function of those factors. A model has also been developed to validate the experimental data and this should help in increasing the efficiency of these processes and reducing the energy input. Moreover, the novel use of ultrasound as a method of measuring progression of the reaction is correlated with in-situ pH monitoring of the reaction process.

Ce travail de thèse examine trois voies de valorisation de l'huile de pépins de raisin au travers de l'élaboration de matériaux polymères auto-associatifs, réticulés ou hybrides. L'huile végétale ou un modèle lipidique (l'oléate de méthyle) sont d'abord fonctionnalisés grâce à leurs insaturations menant à des huiles hydroxylées, aminées, ou phosphorées.Dans une première étude, l'huile et l'oléate de méthyle ont été hydroxylés par réaction thiol-ène. Les alcools gras sont ensuite transformés en macroamorceurs capables d'amorcer la polymérisation cationique par ouverture de cycle de la 2-méthyl-2-oxazoline. Les lipopolymères (LipoPOx) amphiphiles ainsi synthétisés sont capables de s'auto-associer et de former des nanoparticules monodisperses observées par DLS. Dans une deuxième étude, l'huile et certains de ses dérivés amide ont été modifiés sous UV par addition radicalaire du chlorure de cystéamine, conduisant à une diamine linéaire et à une polyamine ramifiée. Ces dernières ont été utilisées comme durcisseurs d'huile époxydée permettant la réticulation de résines époxy à fort taux de carbone biogénique. L'étude thermomécanique par analyse rhéologique montre que ces matériaux thermodurcissables ont des Tg comprises entre -38 et -9°C.Dans une troisième étude, les lipides ont été fonctionnalisés par addition radicalaire de diméthylphosphite par voie photochimique ou thermique. La transformation ultérieure des esters phosphonés en fonctions silylées a rendu ces composés réactifs vis-à-vis du titane et de ses oxydes. L'ancrage de lipides sur des particules de TiO2 ou des feuilles de Titane influe sur leurs propriétés de surface. / This Ph-D work deals with the valorization of grapeseed oil for the preparation of novel and various bio-based polymers. Three pathways are developed starting from lipids and leading to polymeric materials such as self-assembled polymers, thermosets and hybride polymers. First, the vegetable oil and methyloleate were modified using radical addition on their double bonds. Following, hydroxylated, aminated and phosphonated lipids were synthesized.In a first study, the oil was hydroxylated via thiol-ene coupling reaction. The fatty alcohol was then converted into initiator for the cationic ring-opening polymerization of 2-methyl-2-oxazoline. These Lipopolymers so-called LipoPOx exhibit hydrophilic POx block and fatty block. Their amphiphilic nature confer them a self-organization ability in water. A monomodal and narrow distribution of nanoparticles was observed by DLS and AFM.In a second study, the oil and some fatty amides were also functionalized by UV-induced radical addition using cysteamine hydrochloride. A linear diamine and a branched polyamine were synthesized and used as hardeners of epoxidized vegetable oil leading to thermosets with high level of bio-carbone. The investigation on thermo-mechanical properties showed a Tg between -38 and -9°C.In a last study, the lipids were modified by radical addition of dimethylphosphite using thermal or photochemical process. Then, the phosphonate esters were converted into silylated moieties making them reactive toward titanium. The anchoring of lipids onto titanium based materials induced a modification of their surface properties.

A procura dos consumidores por produtos mais saudáveis, combinada às descobertas científicas sobre os efeitos na saúde humana de diversos alimentos, gerou a busca por processos adequados à produção de alimentos. Neste contexto, óleos e gorduras modificados têm ganhado atenção especial. Uma opção industrial para modificar as propriedades dos óleos e gordura é por meio de reações de interesterificação catalisadas por agentes químicos ou bioquímicos. O presente trabalho teve como objetivo, verificar a influência do tipo de catalisador (metóxido de sódio e lipase de Rhizopus oryzae imobilizada em silica-PVA) nas propriedades sensoriais dos produtos obtidos por interesterificação da gordura do leite anidra e dois óleos vegetais (soja e canola). A avaliação sensorial feita através de um nariz eletrônico e um texturômetro, utilizando matérias-primas que estavam de acordo com as normas brasileiras e adequadas para as duas rotas de interesterificação. As reações de interesterificação química foram realizadas em rotaevaporador de baixa pressão contendo 320g da mistura (65% de gordura do leite e 35% de óleo vegetal) e 0,75% de metóxido de sódio a 60°C por 60min. As reações de interesterificação enzimática foram realizadas em reatores cilíndricos encamisados, carregados com 70g de meio (65% de gordura do leite e 35% de óleo vegetal) incubadas com derivado imobilizado na proporção fixa de 500 unidades de atividade por grama de meio (500U/g). As reações foram conduzidas por 6 horas, com agitação magnética, em atmosfera inerte (N2), ao abrigo da luz, a 45°C. Os resultados mostraram que os sensores do nariz eletrônico discriminaram as amostras satisfatoriamente e que o tipo de catalisador influenciou de forma marcante no aroma dos produtos interesterificados, independentemente do tipo de óleo usado. Este fato pode ser atribuído à especificidade do catalisador enzimático (enzima 1,3 específica) que atua nos carbonos 1,3 do glicerol enquanto na interesterificação química a distribuição dos triacilgliceróis ocorre ao acaso, imprimindo no painel dos componentes principais do aroma posições opostas. Especificamente, verificou-se que os aromas dos produtos interesterificados pela rota enzimática ficaram localizados em posição mais próxima à dos óleos vegetais, enquanto pela rota química os produtos obtidos ficaram mais próximos aos componentes dos aromas da gordura de leite e das misturas gordura e óleos vegetais. Apesar desta metodologia não permitir identificar que tipo de aroma poderia ser mais agradável ao consumidor, é possível afirmar que o catalisador tem uma influência importante no aroma de produtos obtidos por interesterificação. Com relação à textura, ambas as rotas geraram produtos com consistências adequadas ao critério estabelecido por Haigton. / Consumers\' demand for healthier products, combined with scientific discoveries about the effects of different foods on human health, has generated the search for suitable processes for the production of food. In this context, oils and modified fats have gained special attention. Reactions catalysed by chemical or biochemical agents are an industrial option to modify the properties of the oils and fat by means of its interesterification. This study aimed to verify the influence of the type of catalyst (sodium methylate and Rhizopus oryzae imobilizada on silica PVA) on the sensory properties of the products obtained by interesterification anhydrous fat milk and two vegetable oils (soybean and canola). Sensory evaluation was made through an electronic nose and texturometer, using raw materials that were in accordance with Brazilian rules and appropriate standards for the two routes of interesterification. The chemical interesterification reactions were performed at low pressure rotaevaporator, the mixture containing 320g (65% milk fat and 35% vegetable oil) and 0.75% sodium methoxide at 60° C for 60min. The enzymatic interesterification reactions were carried out in cylindrical jacketed reactors loaded with 70g of médium (65% milk fat and 35% vegetable oil) incubated with immobilized derivative in a fixed proportion of 500 activity units per gram of reaction medium (500U / g). The reactions were conducted for 6 hours, with magnetic stirring under inert atmosphere (N2), protected from light, at 45 ° C. The results showed that the sensors of the electronic nose discriminated samples satisfactorily and that the type of catalyst influenced markedly in the aroma of interesterified products regardless of the type of oil used. This fact can be attributed to the specificity of the enzyme catalyst (1.3-specific enzyme) that acts on the 1,3 carbons of the glycerol as chemical interesterification of triacylglycerols distribution occurs randomly, printing on the panel of the components of the aroma opposite positions. Specifically, it was found that the scent of interesterified product by enzymatic route were located in the nearest position to the vegetable oil, while by the chemical route the products obtained were closest to the components of milk fat flavors and mixtures fat and vegetable oils . Although this methodology cannot identify what kind of aroma could be more pleasant to the consumer, it is clear that the catalyst has an important influence on product aroma obtained by interesterification. Regarding the texture, both routes generated products with suitable consistency to the criteria established by Haigton.

O objetivo do experimento foi verificar o efeito da adição do óleo de soja, óleo de linhaça, óleo de coco babaçu e sebo bovino na ração de fêmeas suínas lactantes. As dietas eram energeticamente altas, sendo uma dieta basal acrescida em 8% por diferentes fontes de energia, (1) óleo de soja, (2) óleo de linhaça, (3) óleo de coco e (4) gordura animal, tratamentos 1, 2, 3 e 4 respectivamente. O experimento foi realizado na Fazenda Santa Rosa, Leme, SP. As variáveis avaliadas foram peso inicial, aos 100 dias de gestação (PI), peso à desmama (PD), espessura de toucinho aos 100 dias de gestação (ETI), espessura de toucinho à desmama (ETD), mudanças corporais no período lactacional como perda de peso (PP), perda de espessura de toucinho (PET), produção de leite (PL) e peso dos leitões (Ple) nos dias 7, 14 e 21 da lactação, intervalo desmama estro (IDE), duração do estro (DE) e concentrações de estrógeno (Es) à desmama, 48 horas após a desmama e no estro. A espessura de toucinho foi medida no P2. A técnica de PL foi realizada pela técnica de peso dos leitões antes e depois das mamadas. O manejo para diagnóstico do estro foi realizado duas vezes ao dia. As coletas de sangue foram realizadas em 3 ocasiões à desmama (Dia 1), 48 horas após a desmama (Dia 2) e na comprovação do estro (Dia 3). As análises da (Es) foram realizadas pela técnica de radioimunoensaio. Foram utilizadas 24 fêmeas, em um delineamento inteiramente ao acaso. Os resultados foram analisados através do programa computacional Statistical Analysis System (SAS Institute Inc., 1985) submetidos à análise de variância pelo procedimento GLM (PROC GLM). Para os valores de peso, espessura de toucinho, bem como das mudanças no período não houve diferença significativa, e os resultados foram para PI 257,7; 259,3; 265,0 e 267,0 quilos e para PD 231,3; 217,4; 224,9 e 225,0 quilos para os tratamentos 1, 2, 3 e 4, respectivamente. Os valores de 17,0; 16,5; 16,5; 16,0 milímetros foram para ETI e 13,2; 12,13; 12,5 e 12,0 mm para ETD nos tratamentos 1, 2, 3 e 4, respectivamente. A PP durante a lactação foi de 44,4; 41,9; 40,1 e 39,1 para os tratamentos 1, 2, 3 e 4, respectivamente. Já a PET apresentou médias de 3,8; 4,2; 4,0 e 4,0 mm nos tratamentos 1, 2, 3 e 4, respectivamente. Não foi encontrada diferença significativa para PL, bem como para os diferentes dias de mensurações tendo como resultados no 7º dia 10,13; 9,43; 8,98 e 8,85 Kg para os diferentes tratamentos 1, 2, 3 e 4, respectivamente. No 14º dia os valores médios para os tratamentos foram de 10,12; 11,20; 10,26 e 8,79 Kg, respectivamente, e os valores de 11,34; 10,47; 10,56 e 10,76 Kg para os tratamentos 1, 2, 3 e 4, respectivamente para o 21º dia. O peso dos leitões não foi significativo entre os tratamentos, mas apresentou significância nos três diferentes tempos (P < 0,01) e os valores médios foram de 2,87; 2,95; 2,83 e 2,9 Kg para os tratamentos 1, 2, 3 e 4, respectivamente para o 7º dia de amamentação, de 5,01; 4,88; 4,8 e 4,75 Kg nos tratamentos 1, 2, 3 e 4, respectivamente para 14º dia. Já para o 21º dia os valores nos tratamentos 1, 2, 3 e 4, respectivamente foram de 6,80; 6,58; 6,56 e 6,82 Kg. O IDE e DE não apresentaram diferença significativa e tiveram como médias nos respectivos tratamentos 1, 2, 3 e 4 de 74,0; 68,0; 70,3 e 78,7 horas para IDE e 57,6; 62,0; 64,0 e 72,0 para DE. Para as médias de Es não houve significância e estas apresentaram os seguintes valores de 10,25; 12,82; 9,65 e 8,71 pg/ml nos respectivos tratamentos 1, 2, 3 e 4 no dia 1. Para o dia 2 os valores nos tratamentos 1, 2, 3 e 4 foram de 25,8; 27,39; 24,64 e 32,12 pg/ml respectivamente, e os valores de 83,6; 79,14 e 77,64 pg/ml para os tratamentos 1, 2, 3 e 4, respectivamente referentes ao dia 3. / Twenty-four Dalland C40 sows were used in one experiment to study the effect of dietary vegetable oil or tallow on productive and reproductive parameters. All sows were fed a corn-soybean meal diet supplemented with 8% soybean (T1), linseed (T2), coconut (T3) oil or tallow (T4) from day 100 of gestation and throughout the lactation period. Sow initial weight and backfat thickness were determined at day 100 of gestation (ISW and IBT, respectively), and at weaning (WSW and WBT, respectively). Sow weight and backfat thickness losses (WL and BTL, respectively) were calculated, and milk yield (MY) was estimated at day 7, 14 and 21 of lactation by weighing the litter before and after suckling. Interval weaning estrus (IWE), and estrus duration (ED), and piglet weight (PW) were recorded. Blood samples were taken at weaning (day 1), and 48 hours after weaning (day 2), and at onset of estrus (day 3) for estradiol (E2) determination. There were no treatment effects for the parameters studied. The means for E2 were 10.25; 12.82; 9.65 e 8.71 pg/ml (day 1), and 25.8; 27.39; 24.64 e 32.12 pg/ml (day 2), and 83.6; 79.14 e 7764 pg/ml (day 3) for treatment 1, 2, 3 e 4, respectively. Means for E2 on day 3 were higher than values observed on day 1 and 2.

A cárie dental ainda afeta grande número de pessoas no mundo todo. Sua ocorrência depende da formação, sobre a superfície dentária, de um biofilme microbiano. As interações entre microrganismos do biofilme e os componentes da dieta, podem interferir de diferentes formas nessa patologia, pois alguns componentes alimentares atuam favorecendo o aparecimento de lesões, tal como os carboidratos, enquanto outros, atuam inibindo, como ácidos graxos, polifenóis, caseína e lectina. O tucumã (Astrocaryum vulgare) e a pupunha (Bactries gasipae) são frutos oleaginosos nativos da Região Amazônica, que apresentam alto teor lipídico e de carotenos. Assim, o objetivo deste estudo foi avaliar a influência dos óleos extraídos da polpa destes frutos na composição do biofilme dental e dinâmica do processo de desmineralização em esmalte. Os óleos foram extraídos sem adição de solventes, caracterizados e misturados a uma solução de 20% de sacarose, para serem testados por meio de um modelo de estudo in situ. Oito voluntários utilizaram dispositivos palatinos contendo 4 blocos de esmalte dental, durante 3 fases de 14 dias cada (n=96). As soluções controle (sacarose 20%) e as soluções com óleos testadas, foram aplicadas sobre os blocos de esmalte 8 vezes ao dia, de 2 em 2 horas. A cada 7 dias, foram coletados 2 blocos de esmalte e o biofilme formado sobre esses blocos. A análise do biofilme compreendeu avaliação da quantidade de unidades formadoras de colônia (UFC) de Streptococcus mutans, Streptococcus totais e Lactobacillus casei; dosagem de carboidratos totais e dosagem da capacidade antioxidante equivalente ao Trolox (TEAC). A perda mineral dos blocos de esmalte foi avaliada por meio da microdureza superficial Knoop e Tomografia por Coerência Óptica (OCT). Utilizou-se o programa BioEstat 5.0 para a análise estatística, com nível de significância de ?=0,05. A análise do biofilme mostrou que o grupo tucumã (GT)-14dias e grupo pupunha (GP)-7dias apresentaram a menor quantidade de UFC do total de microrganismos, diferindo estatisticamente dos grupos sacarose (GS)-7 e 14dias, GT-7dias e GP-14dias (p<0,05). O grupo GT-7 e 14 dias mostraram dosagens de TEAC semelhantes estatisticamente ao grupo GS-7 e 14dias. O grupo GP apresentou os menores valores de TEAC e de carboidratos totais. Não houve diferença estatística intragrupos nos diferentes tempos experimentais, relacionados ao TEAC e carboidratos totais. A análise da perda de dureza superficial (PDS), coeficiente de atenuação óptica e área sob a curva do sinal de OCT mostraram que o grupo GP-7dias apresentou a menor perda mineral superficial e subsuperficial. A variável TEAC revelou correlação positiva moderada com carboidratos, Streptococcus mutans, Streptococcus totais e PDS sugerindo que o ambiente redox possa ter influenciado e mediando as reações no biofilme. Concluiu-se que os óleos testados reduziram a agregação bacteriana e a perda mineral, sendo que o óleo de tucumã apresentou efeito tardio, enquanto que o óleo da pupunha mostrou resultado mais imediato. O óleo da pupunha por ter apresentado ação nos processos iniciais de formação do biofilme pode ser considerado mais efetivo na prevenção à cárie dental. / Dental caries still affects many people worldwide. Its occurrence depends on the formation of a biofilm on the tooth surface. The interaction between biofilm microorganisms and the components of the diet can interfere in different ways in this pathology, as some food components act favoring the appearance of lesions, such as carbohydrates, while others, act by inhibiting it, such as fatty acids, polyphenols, casein and lectin. Tucumã (Astrocaryum vulgare) and peach palm (Bactries gasipae) are oleaginous fruits native from the Amazonia, which have a high lipid content and carotenes. The objective of this study was to evaluate the influence of the oils extracted from the pulp of these fruits on dental biofilm composition and dynamics of enamel demineralization. The oils were extracted without addition of solvents, characterized and mixed with a 20% sucrose solution, to be tested under an in situ study model. Eight volunteers wore palatal appliances containing 4 dental enamel blocks during 3 phases of 14 days each (n = 96). The control (20% sucrose) and experimental solutions (addition of the oils) were applied on the enamel blocks 8 times per day, every 2 hours. Every 7 days 2 enamel blocks were removed and biofilm formed on their surfaces were collected. The analysis comprised the assessment of biofilm forming units (CFU) of Streptococcus mutans, Streptococcus total and Lactobacillus casei, and the dosage of both the total carbohydrates and the Trolox equivalent antioxidant capacity (TEAC). The mineral loss of enamel blocks was evaluated by Knoop microhardness and Optical Coherence Tomography (OCT). The BioEstat 5.0 was used for statistical analysis with a significance level of ? = 5%. The biofilm analysis showed the least amount of CFU of total microorganisms on group tucumã (GT)-14days and group pupunha (GP)-7days, differing from groups of sucrose (GS)-7 and 14days, GT-7days and GP-14days (p<0,05). The GT-7 and 14days showed statistically similar doses of TEAC compared to groups GS-7 and 14days. The GP group showed the lowest values of TEAC and total carbohydrates. With respect to TEAC and total carbohydrates, there was no statistical difference among groups in different experimental times. The analysis of surface hardness (SMH) loss, optical attenuation coefficient and area under the curve of the OCT signal showed that group GP-7days had the lowest surface and subsurface mineral loss. The TEAC variable showed moderate positive correlation with carbohydrates, Streptococcus mutans, Streptococcus total and SMH, suggesting that the environment is influencing and mediating redox reactions in the biofilm. It was concluded that all the oils reduced bacterial aggregation and mineral loss, and that the tucumã oil presented a late effect, while the peach palm oil showed a most immediate result. As the peach palm oil was shown to act during the initial processes of biofilm formation it can be considered more effective in preventing dental caries.

A demanda pelo uso de formulações biodegradáveis e provenientes de fontes renováveis tem motivado o desenvolvimento de biofluidos de resfriamento para aplicação em têmpera de aços. Os óleos vegetais são potenciais candidatos a serem empregados como base destas formulações, porém, a baixa estabilidade termo-oxidativa inibe sua maior utilização pela indústria. As modificações químicas na cadeia carbônica dos óleos vegetais podem promover melhoria nesta característica, sendo epoxidação uma das mais comuns. O presente trabalho estudou, primeiramente, a estabilidade termo-oxidativa de formulações contendo óleo de soja epoxidado (ESBO) e éster metílico de ácido graxo (FAME), em diferentes concentrações, por Calorimetria Exploratória Diferencial com Pressão (PDSC). Posteriormente, o desempenho destes biofluidos, no tratamento térmico de têmpera, foi avaliado pela análise microestrutural e medições de dureza (curvas em U) nos aços SAE 1045 e SAE 4140, comparando-o com o desempenho promovido pelos fluidos derivados de petróleo. As tensões térmicas residuais foram simuladas com o ABAQUS, usando os coeficientes de transferência de calor obtidos pela solução do problema inverso. As distorções causadas pelos biofluidos foram estudadas em corpos Navy-C-rings modificados de aço SAE 4140. Além disto, a viscosidade dos biofluidos também foi estudada em função da temperatura por estar diretamente relacionada à propriedade de molhamento, que influencia a transferência de calor durante o processo de resfriamento. A adição de FAME no ESBO foi eficiente na redução da viscosidade das formulações propostas, em função da temperatura, adequando-as para utilização como fluidos de resfriamento. As formulações EF30 e EF38 apresentaram temperatura inicial de oxidação (OOT) superior ao óleo de soja, indicando assim, maior estabilidade termo-oxidativa. Todas bioformulações foram eficientes na têmpera de ambos os aços, nos diâmetros ensaiados, promovendo dureza mínima de aproximadamente 52 HRC no centro dos corpos SAE 4140, dureza esta, comparável àquela promovida pelos fluidos minerais. Comportamento similar foi observado para o aço de menor temperabilidade. As tensões térmicas residuais simuladas não variam em magnitude em função da composição das formulações, enquanto que as distorções tenderam a aumentar em função do aumento do FAME nas formulações. / The search for biodegradable and renewable basestocks has motivated the development of bioquenchants for steel heat treatment. Vegetable oils are potential candidates, however, their poor thermo-oxidative stability inhibits a wide industrial application. Modifications of the chemical structure of vegetable oils may be used to improve this characteristic and epoxidation is one of the most common approaches reported to date. The first step of the study reported here was to analyze and compare the thermo-oxidative stability of soybean oil, epoxidized soybean oil (ESBO) and different blend ratios of ESBO with a soybean oil-derived fatty acid methyl ester (FAME) by Pressure Differential Scanning Calorimetry (PDSC). Subsequently, the quenching performance of the formulations was evaluated by cooling curve analysis and microstructural analysis and hardness measurements by U-curves analysis of SAE 1045 and SAE 4140 steels and then, compared with results obtained using commercially available petroleum oil quenchants. Thermal residual stress profiles were simulated with ABAQUS, using the heat transfer coefficients obtained by an inverse method. Bioquenchant distortions were determined using SAE 4140 steel and a so-called modified Navy C-ring test. Moreover, the viscosity-temperature property of bioquenchants was also studied, since it is directly related to the heat transfer and wetting behavior occurring during the cooling process. Although the viscosity of ESBO was too high for use as a quenchant, increasing FAME addition to ESBO provided sufficient reduction of resulting kinematic viscosities to permit their potential use as quenchants. EF30 and EF38 (30% and 38% FAME, respectively) exhibited onset oxidation temperatures (OOT) higher than soybean oil, thus indicating better thermo-oxidative stability. All bioquenchants were effective for both steels, at the specimen diameters tested, producing a minimum hardness of approximately 52 HRC at the center of the SAE 4140 test specimen. This hardness is comparable to that obtained with the petroleum-based fluids. Comparable results were obtained for the lower hardenability SAE 1045 steel. The simulated residual stress profiles did not vary in terms of magnitude as a function of formulation composition while the distortions tended to increase as FAME is added in the formulations.