Search

Onion peels have considerable amounts of bioactive compounds with high antioxidant capacity. This study aimed to assess the antioxidant capacity of yellow, white, and purple onion peel extracts and to analyze their antioxidant effects on the thermo-oxidative stability of soybean oil. The extracts were assessed regarding the total phenolic compounds and antioxidant activities. The oil was supplemented with extracts of onion peel, tocopherol, ascorbyl palmitate, and tert-butylhydroquinone, whether isolated and combined. The treatments were subjected to thermo-oxidation and the samples were analyzed for oxidative stability, total polar compounds, and tocopherols content. The purple onion peel extract showed the highest efficiency in phenolic compounds and antioxidant activity. In the oxidative stability analysis, OAP, OTBHQ and OPE+OTBHQ (synergistic effect) stood out. Total polar compounds were elevated in SO, OTOC, and OTOC+OAP at 8 hours, and all treatments exceeded the 25% limit at 16 hours. δ-tocopherol showed greater retention at the end of 16 hours in the OPE treatment with 51.54%. Therefore, the use of purple onion peel extract can delay oxidation and contribute to the retention of tocopherols, enabling the use of lower concentrations of synthetic antioxidants.

Este trabalho teve como objetivos caracterizar as sementes de chia (Salvia hispanica L.), gergelim (Sesamum indicum L.) e linhaça (Linum usitassimum L.) quanto à composição centesimal, bem como avaliar as propriedades físico-químicas e capacidade antioxidante dos seus óleos. As sementes apresentaram elevadas quantidades de lipídios (31,3%–46,7%) e proteínas (16,6%–25,5%). O óleo de chia mostrou maior degradação hidrolítica e oxidativa devido aos índices de acidez (5,27 mg KOH/g), peróxidos (2,76 meq/kg), ρ-anisidina (3,15) e, consequentemente, o valor Totox (8,79). Quanto aos ácidos graxos, os óleos mostraram ser predominantemente constituídos por ácidos graxos insaturados, sobressaindo o de chia com maior quantidade de ácido α-linolênico (58%). Os óleos de gergelim mostraram quantidades consideráveis de tocoferóis totais (2538,10 mg/kg–2645,59 mg/kg). O óleo de gergelim branco mostrou teor significativo de carotenoides totais (128,44 µg β-caroteno/g), enquanto o de linhaça dourada se destacou com maior conteúdo de fenólicos totais (287,29 mg/kg) e o de chia com 199,03 mg/kg de fitosteróis totais. Os óleos avaliados também demonstraram elevada capacidade antioxidante. Assim, é possível concluir que são óleos importantes do ponto de vista funcional, devido à presença de compostos bioativos.

ABSTRACT The bioactive compounds and the antioxidant capacities of mangaba, mango and papaya oils were investigated. Determinations of fatty acid composition, tocopherol, phytosterols, phenolic compounds profile, total carotenoids, and antioxidant activity were carried out in the oils of mangaba, mango and papaya seeds. The analysis of antioxidant activity was performed by the methods DPPH•, ABTS•+, FRAP, and β-carotene/linoleic acid. Only essential fatty acid C18:2 was detected, in an average of 6.2%. In contrast, the main fatty acids quantified were oleic, palmitic, and stearic. The amount of phytosterols in mangaba (1951.7 mg kg-1), papaya (3540.3 mg kg-1), and mango (4565.7 mg kg-1) oils was higher than that of conventional oils, such as soybean oil. α-tocopherol was the main tocopherol found in all oils analyzed. Quantities of phenolic compounds were found only in mango seed oil. Papaya seed oil showed high quantity of total carotenoids (49.90 µg g-1). The possible use of the seeds studied to produce oils appears to be favorable. The information available in this study is of great importance for investigations regarding the use of vegetable oils as raw material for food, pharmaceutical, and chemical industries.

The tomato processing industry generates a large amount of waste, usually composed of peels and seeds. It is known that the tomato is rich in bioactive compounds, mainly carotenoids (lycopene and β-carotene), however, studies on the functionality of its residues are scarce. Thus, these residues are discarded without the knowledge of possible antioxidant potential. The objective of this work was to determine the stability of bioactive in soybean oil added to the extract of agroindustrial tomato waste under heating. The extract obtained with ethyl alcohol at the ratio of 1:5 (w/v) was initially analyzed for total phenolic compounds, lycopene, β-carotene, and antioxidant activity using the DPPH and β- carotene / linoleic acid. Subsequently, the extract and the synthetic antioxidants, butylhydroxytoluene (BHT) and tert-butylhydroquinone (TBHQ) were applied in soybean oil, and the treatments subjected to heating in Rancimat (180ºC/5 h). The thermoxidated samples were analyzed for the composition of tocopherols by high-performance liquid chromatography (HPLC), phytosterols, and fatty acid profile by gas chromatography (GC). The extract of agro-industrial tomato residues showed moderate results concerning its antioxidant activity, 68% by the DPPH method, and 26.2% of auto-oxidation of the β-carotene / linoleic acid system. The synthetic antioxidant TBHQ had a greater protective effect on soybean oil when compared to the control, providing greater retention of phytosterols (85%) and tocopherols (93%). Tomato extract can be used as a natural antioxidant in industrialized oils, but with less effectiveness than the antioxidant TBHQ.

RESUMO: O trabalho teve como objetivo avaliar o potencial antioxidante do extrato de Curcuma longa L. na estabilidade oxidativa do óleo de soja. Para isso, os tratamentos Controle (óleo de soja), TBHQ100 (óleo de soja com 100 mg de TBHQ/kg), Extrato100 (óleo de soja com 100 mg de β-caroteno de extrato/kg) e TBHQ50+Extrato50 (óleo de soja com 50 mg de TBHQ/kg de óleo de soja + 50 mg de β-caroteno de extrato/kg) foram submetidos ao teste acelerado em estufa (60 ºC/20 dias). O extrato apresentou 51,17% de atividade antioxidante pelo método DPPH• e 98,74 μM Trolox.g-1 pelo FRAP, além de 457,9 μg β-caroteno.g-1. Embora, inicialmente, todos os tratamentos tenham apresentado baixos valores de índice de peróxidos (0,55-0,65 meq.kg-1), em 20 dias, o Controle mostrou maior degradação oxidativa, 46,15 meq.kg-1. O TBHQ100 e TBHQ50+Extrato50 apresentaram os menores valores de p-anisidina. Apesar do TBHQ100 ter apresentado maior estabilidade oxidativa (8,25 h), o TBHQ50+Extrato50 (6,41 h) mostrou maior estabilidade que o Controle (3,86 h). Todos os tratamentos apresentaram elevadas concentrações do isômero γ-tocoferol. O antioxidante sintético provou ser mais eficiente na prevenção da reação de oxidação do que o antioxidante natural, visto que possui elevado grau de pureza. Entretanto, o TBHQ50+Extrato50 apresentou resultados satisfatórios, sendo o segundo melhor tratamento capaz de reduzir as alterações do óleo de soja, possibilitando a aplicação para a redução da concentração do antioxidante sintético. PALAVRAS-CHAVE: Atividade antioxidante, Carotenoides, Tocoferóis.

The aim of the study was to characterize the pulp oil of bacuri Attalea phalerata Mart. ex Spreng. (Arecaceae) according to official analytical methods. Total phenolic and carotenoids contents were evaluated by spectrophotometry, and tocopherols composition by high-performance liquid chromatography. The fatty acid profile was obtained through gas chromatography from samples transesterified with potassium hydroxide in methanol and n-hexane. According to the proximate composition, bacuri pulp contained 41.5 % carbohydrates and 39.2 % lipids. Regarding its physicochemical properties, the oil showed a free fatty acids content of 0.7 %, a peroxide value of 1.4 meq/kg, a refractive index of 1.463, an iodine number of 84.3 g I2/100 g, a saponification number of 193.5 mg KOH/g, an unsaponifiable matter of 0.5 %, and 48.7 h of oxidative stability. Total phenolic, carotenoids, and tocopherols contents recorded values of 2.4 mg GAE/g, 243.0 µg/g, and 86.8 mg/kg, respectively. The bacuri oil showed a fatty acid composition similar to olive oil and a high percentage of unsaturation, finding 67.3 % of monounsaturated acids, and 11.3 % of polyunsaturated acids. The main fatty acids were oleic (67.3 %), palmitic (13.3 %), and linoleic (10.5 %). Due to its physicochemical characteristics, bacuri oil has a great potential to be used in food preparations, such as salad oil or in margarine formulation.

Coffee husk can be removed from the grain mainly by two different ways: the wet method and the dry method. Aiming to add value to the by-products of the coffee agroindustry, we analyzed the antioxidant properties of hydroalcoholic extracts of coffee husks obtained from the two different methods. The production of the extract followed a rotational central composite design, varying the ethanol proportion and the ultrasound exposure time in between. The results of the experimental planning were: extract volume yield; total phenolic compound and antioxidant activity expressed by the DPPH and FRAP methods. Mathematical models were constructed using the significant parameters for each response, and its predictive capacity was evaluated through an analysis of variance of the regression. Better results were found in extracts from husk obtained by the dry method using solvent in a proportion of 40-50% (v v-1) ethanol to 40-60 min. of ultrasound exposure.

Due to the increasing production of food in the world with consequent increase of the production of waste, the importance of developing researches for its use is noticed. Thus, the interest in vegetable oils with bioactive compounds, such as the ones extracted from fruit seeds, is growing. Therefore, the present study aims to characterize the oils extracted from seeds of Hamlin, Natal, Pera-rio and Valencia orange varieties (Citrus sinensis), as to the levels of total carotenoids, total phenolic compounds, tocopherols and phytosterols, as well as to determine their antioxidant activity. The orange seed oils presented important content of total carotenoids (19.01 mg/kg), total phenolic compounds (4.43 g/kg), α-tocopherol (135.65 mg/kg) and phytosterols (1304.2 mg/kg). The antioxidant activity ranged from 56.0% (Natal) to 70.2% (Pera-rio). According to the results it is possible to conclude that the orange seed oils can be used as specialty oils in diet, since they contain considerable amounts of bioactive compounds and antioxidants.

No presente trabalho foram avaliados óleos de fritura utilizados pela cantina localizada no IBILCE/UNESP em São José do Rio Preto-SP. Os objetivos foram determinar os níveis de alteração dos mesmos e conscientizar o estabelecimento quanto às boas práticas de fabricação, tendo em vista o fornecimento de alimentos de melhor qualidade à população. Para isso, as seguintes metodologias foram usadas: determinação de compostos polares totais, porcentagem de ácidos graxos livres, ensaio Oil Test, ácidos dienóicos conjugados, índice de peróxidos e perfil de ácidos graxos. Os limites de alteração estabelecidos foram baseados na legislação adotada por alguns países: 25% para compostos polares totais, 1% para ácidos graxos livres e 10 meq/kg para índice de peróxidos. Os resultados obtidos indicaram que 53,2% das 47 amostras analisadas para compostos polares totais se encontraram acima do limite; 77,8% das 9 amostras cujo teor de ácidos graxos livres foi analisado excederam o limite de 1% e; 33,3% das 9 amostras avaliadas quanto ao índice de peróxidos obtiveram valor maior que 10 meq/kg, ultrapassando o limite estabelecido. Os teores de ácidos dienóicos conjugados oscilaram entre 0,36 e 2,43%, com valor médio de 1,57%. Quanto ao ensaio Oil Test, verificou-se que seria recomendada a troca do óleo para 66,7% das amostras analisadas, pois os resultados obtidos na escala colorimétrica indicaram o nível de alteração ‘trocar’. Na avaliação do perfil de ácidos graxos dos óleos, foram predominantes os ácidos graxos poli-insaturados, que apresentaram diminuição na porcentagem ao longo de cada ciclo de fritura. Diferentemente, os ácidos graxos saturados e monoinsaturados apresentaram aumento. Os resultados das determinações analíticas reforçam a importância de se avaliar e controlar as alterações sofridas pelo óleo durante o processo de fritura, para que o estabelecimento possa oferecer alimentos fritos de qualidade ao consumidor.

ABSTRACT The oxidative stability of linseed (L), cotton (A), and coconut (C) oils, as well as of linseed:cotton (LA), linseed:coconut (LC), and linseed:cotton:coconut (LAC) compound oils was evaluated under accelerated storage at 60°C/20 days. Coconut oil showed to be rather stable, mainly due to low levels of peroxides, conjugated dienes, ρ-anisidine, and long induction period. In addition, along with cotton oil, it improved the stability of linseed oil in the formulation of LAC compound oil. As to fatty acid profile, the compound oils showed to be composed mainly by unsaturated fatty acids. Cotton and coconut oils presented higher retention of total phytosterols, 78.87 and 76.16%, respectively, after 20 days of storage, when compared to linseed oil. The highest retention of total tocopherols at the end of storage was observed in LA (90.81%). In relation to antioxidant activity, by the DPPH method, with the increase in storage time, a reduction in the antioxidant substances of linseed, LC, and LAC oils was observed. Through the FRAP method, oscillations were observed, especially in linseed and compound oils. Although the oils were degraded over time, it was possible to verify that cotton and coconut oils contributed to increase the stability of linseed oil, which, in turn, raised the levels of coconut oil bioactive compounds.

Avocado oil is rich in bioactive compounds, which can improve human health by acting as an antioxidant. It may be extracted from different varieties of avocado, such as Margarida and Hass varieties, each of them with particular characteristics. Aiming to evaluate the differences between them, avocado fruits and pulps from these were analyzed according to their physicochemical characteristics. After extracted, the oils had their bioactive characteristics studied and rheological behavior determined through a rotational rheometer. They were then compared to commercial avocado oil. The fruits of Margarida variety had greater size, higher weight (664.51 g), and higher pulp yield (72.19%) than Hass variety, which showed higher lipid content (65.29 g/100 g dry basis). The commercial oil showed less primary oxidative degradation, whereas Margarida variety had a lower level of secondary degradation products as well as a higher content of bioactive compounds, such as phytosterols (999.60 mg/kg) and tocopherols (36.73 mg/kg). The rheological behaviors of both oils were appropriately described through Newton model, with R2 > 0.999 for all temperatures. By an Arrhenius type equation, it was verified that Hass's rheological parameters are more influenced by temperature than Margarida and commercial oil, presenting activation energy of 33.6 kJ/mol.

It is extremely important to evaluate the extraction processes of vegetable oils used in food, considering that the nuts are rich sources of triacylglycerols. Thus, the present study aimed at comparing the methods of solvent extraction and extraction by pressing of the lipid fractions of walnut (Juglans regia) and pecan nut (Carya illinoensis), in order to elucidate their influence on the content of bioactive substances. The samples were analyzed regarding fatty acid profile, tocopherols, phytosterols, carotenoids, and phenolic compounds, presenting relevant quantities of these bioactive substances. It was found that the extraction of oils by pressing minimized degradation of tocopherol when compared to solvent extraction. However, solvent extraction is more efficient to extract bioactive compounds such as phytosterols, carotenoids, and phenolic compounds.

Frying is a widely used method of preparing food, because it is a very fast and convenient process, and because it provides specific characteristics of color, flavor, odor, and texture, besides having great consumer acceptance. Therefore, the interest in the physiological effects that oils heated at high temperatures can cause to the human body arises. The aim of this work was to analyze the levels of frying used oil alteration in different kinds of foods served at the university restaurant at “Instituto de Biociências, Letras e Ciências Exatas” (IBILCE), in São José do Rio Preto-SP. In addition, it aims to make the restaurant aware of the good ways to fry and the commitment of providing good quality food to students and professionals of the Institute. With this purpose, determination of total polar compounds, conjugated dienoic acids, peroxide value, and fatty acid profile were analyzed. Two rapid tests were also used: 3M Fat Monitor and Oil Test kit. The results were compared with limits recommended for the disposal of oils and fats used in frying by the Brazilian Health Surveillance Agency (ANVISA), by other countries, and by other researches. Thus, it was concluded that the university restaurant provides the consumers with fried food of good quality, since none of the analyses showed results above recommended, although there is a need of improvement in the quality control of the oil used, in order to avoid unnecessary costs to the university restaurant.

Os frutos de Pachira aquatica Aublet apresentam sementes comestíveis com características organolépticas muito apreciadas pelas populações amazônicas, sendo pouco utilizados em outras regiões. Este trabalho teve como objetivo caracterizar as sementes quanto à composição centesimal e determinar as características físico-químicas e perfil de ácidos graxos. A determinação da composição centesimal das sementes (teores de umidade, lipídios, proteínas, cinzas e carboidratos) e análises do óleo extraído das mesmas (ácidos graxos livres, índices de peróxido, iodo, refração, saponificação, ponto de fusão e perfil de ácidos graxos) foram realizadas seguindo metodologia oficial. O teor de óleo nas sementes 38,39% demonstrou que estas têm potencial para aproveitamento industrial. Das características físico-químicas analisadas, o óleo extraído das sementes apresentou 39,2% de ácidos graxos livres (expresso em % ácido oleico), índice de iodo de 27,4 g I2.100 g-1, índice de saponificação de 208,0 mg.KOH g-1, índice de refração (40 °C) de 1,4569 e ponto de fusão de 41,9 °C. Quanto à composição de ácidos graxos do óleo predominaram os ácidos palmítico (44,93%), oleico (39,27%) e linoleico (11,35%). Tal fato favorece o uso deste óleo como matéria-prima para as indústrias alimentícia, farmacêutica e de cosméticos.The fruits of Pachira aquatica Aublet present edible seeds with organoleptic characteristics much appreciated by peoples in the Amazon, with little being used in other regions. This study aimed to characterize the seeds and to determine the composition and physicochemical characteristics and fatty acid profile. Determining the composition of the seeds (moisture, lipids, proteins, carbohydrates and ash) and analysis of oil extracted from them (free fatty acids, peroxide, iodine, refractive index, saponification value, melting point and fatty acid profile) was performed following the official methodology. The oil content in the seeds 38.39% showed that these have potential for industrial use. The physical and chemical analysis, the oil extracted from the seeds showed 39.2% of free fatty acids (% oleic acid), iodine value of 27.4 I2.100 g-1, saponification number of 208.0 mg.KOH g-1, refractive index (40 °C) of 1.4569 and melting point of 41.9 °C. Regarding the composition of fatty acids palmitic predominated oil (44.93%), oleic (39.27%) and linoleic (11.35%). This fact favors the use of oil as raw material for the food, pharmaceutical and cosmetic industries.

The aim of this study was to determine the chemical composition -physico-chemical properties, fatty acid and tocopherol compositions and total phenolic compounds -and evaluate the radical-scavenging activity of crude oil extracted from passion fruit (Passiflora edulis f. flavicarpa) seeds, aiming to use the agro-industrial by-products. The oil seed extraction was performed by Soxhlet method and the oil yield from the seeds was 30.39%. The oil showed high levels of unsaturated fatty acids (87.59%), including mainly linoleic (73.14%) and oleic (13.83%) acids, tocopherol (499.30 mg/kg) and phenolic compounds (1,314.13 mg GAE/kg). The physico-chemical characteristics were similar to those of other edible oils and the oil showed significant antioxidant activity. Therefore, the potential utilization of the passion fruit seed oil as a raw material for food, chemical and pharmaceutical industries could be favorable.

This study evaluated the antioxidant activity of passion fruit seeds extract in soybean oil. Dried seeds were ground and submitted to extraction with ethanol:water (95:5), for two hours, at room temperature. The resulting extract was centrifuged and the supernatant evaporated for dry extract yield calculation. The extract of passion fruit seeds was suspended again in ethanol:water (95:5) and applied to soybean oil in two concentrations (500 mg kg-1 and 1,000 mg kg-1), being submitted to oven accelerated test at 60oC, for 20 days. Oil samples were taken every 5 days and analyzed for peroxide value. As a parameter of comparison, it was used butyl hydroxytoluene (BHT) as well as refined soybean oil without antioxidants (control). In the extract, the antioxidant activity was measured by the DPPH radical method and total phenols by using the Folin-Ciocalteau method. The yield of dry extract was 1.26%, the IC50 value was 113.41 µg mL-1, and the concentration of total phenolic compounds was 42.93 mg of gallic acid per gram of extract. At the final heating time, peroxide values were significantly different and the antioxidant activity order was: BHT > passion fruit 500 mg kg-1 > passion fruit 1,000 mg kg-1 > control. KEY-WORDS: Antioxidants; passion fruit seeds; peroxide value; proximal composition. Este trabalho consistiu em avaliar a atividade antioxidante do extrato de sementes de maracujá em óleo de soja. As sementes desidratadas foram trituradas e submetidas à extração em etanol:água (95:5), por duas horas, à temperatura ambiente. O extrato resultante foi centrifugado e o sobrenadante rotoevaporado, a fim de se calcular o rendimento de extrato seco. O extrato de sementes de maracujá foi ressuspenso no mesmo solvente utilizado para a extração e aplicado no óleo de soja, em duas concentrações (500 mg kg-1 e 1.000 mg kg-1), sendo submetido ao teste acelerado de estufa, a 60ºC, por 20 dias. Amostras de óleo foram retiradas a cada 5 dias e analisadas quanto ao índice de peróxidos. Como parâmetro de comparação, foi utilizado butil hidroxitolueno (BHT), bem como o óleo de soja refinado, isento de antioxidantes (controle). No extrato, a atividade antioxidante foi mensurada pelo método do radical DPPH e a concentração de compostos fenólicos totais pelo método de Folin-Ciocalteau. O rendimento em extrato seco foi 1,26%, o valor de CE50 encontrado foi 113,41 µg mL-1 e a concentração de compostos fenólicos totais foi 42,93 mg de ácido gálico/g de extrato. Para o tempo final de estufa, os valores de peróxidos diferiram significativamente entre si e a ordem de atividade antioxidante foi: BHT > maracujá 500 mg kg-1 > maracujá 1.000 mg kg-1 > controle. PALAVRAS-CHAVE: Antioxidantes; sementes de maracujá; índice de peróxidos; composição centesimal.

Conduziu-se este trabalho, com o objetivo de avaliar a atividade antioxidante de diferentes extratos de cogumelo Agaricus blazei, bem como a estabilidade oxidativa do óleo de soja adicionado de extrato de cogumelo. O cogumelo seco em estufa a 55ºC e triturado (10 g) fui submetido à extração, à temperatura ambiente, com 100 mL de metanol e metanol:água (1:1) com duração de 6 e 12 horas para ambas as extrações. O extrato de maior atividade antioxidante, conforme o método DPPH, foi aplicado em óleo de soja na concentração de 0,1% de compostos fenólicos totais e, então, submetido ao método do Rancimat e ao teste acelerado em estufa a 60ºC por um período de 16 dias. Amostras de óleo foram retiradas da estufa cada 4 dias e analisadas quanto ao índice de peróxidos e dienos conjugados. Como parâmetros de comparação, foram utilizados os antioxidantes sintéticos BHT (100 mg/kg), TBHQ (50 mg/kg) e o óleo de soja isento de antioxidantes (controle). Os resultados demonstraram que o extrato metanólico:aquoso, com 6 horas de extração, apresentou maior atividade antioxidante. A aplicação desse extrato em óleo de soja proporcionou a seguinte ordem em relação à estabilidade oxidativa: TBHQ > extrato de cogumelo > BHT = óleo de soja (controle). O extrato de cogumelo também foi eficiente em relação à formação de peróxidos e dienos conjugados que, apesar de aumentarem ao longo do tempo, foi menor que o BHT, porém maior que o TBHQ. O extrato de cogumelo apresentou-se efetivo na proteção do óleo, podendo ser considerado um potencial antioxidante natural.The present paper had the objectives of measuring the antioxidant activity of different extracts of the mushroom Agaricus blazei and evaluating the oxidative stability of soybean oil added with the mushroom extract. The mushroom dried in stove at 55ºC and ground (10g) was submit to extraction with 100 mL methanol and methanol:water (1:1) for six and 12 hours, respectively, at room temperature. The extract with the highest antioxidant activity, according to the DPPH method, was added to the soybean oil at the concentration of 0.1% total phenolic compounds and then submitted to the Rancimat method and to the accelerated test in stove at 60ºC for 16 days. Samples of oil were withdrawn every four days and the rate of peroxides and conjugated dienes were analyzed. The synthetic antioxidants BHT (100 mg/kg), TBHQ (50 mg/kg), and antioxidant-free soybean oil (control) were used as comparison parameters. The results showed that the methanol:water extract resulting from six hours of extraction presented the highest antioxidant activity. The oxidative stability of the mushroom extract, the synthetic antioxidants, and the control followed the sequence: TBHQ > mushroom extract > BHT = soybean oil (control). The mushroom extract was also efficient regarding the formation of peroxides and conjugated dienes. Despite the increase of these compounds over the time, the extract was less efficient than BHT and more efficient than TBHQ. The mushroom extract has shown effective in the protection of the oil, bearing the potential of a natural antioxidant.

The present study was aimed at verifying tocopherols losses and oxidative stability changes in vegetable oils used in discontinuous frying. The frying of frozen cassava chips was carried out in a household electric frying pan, where the oil was heated to a temperature of 180°C for 25 hours, with fresh oil replacement. The results obtained from the analytical determinations were submitted to variance analysis, in a factorial scheme, using a completely randomized design, making it possible to determine the influence of the type of oil and frying times on changes in the oil. The data show that the smallest changes occur in palm oil, which is more saturated. For sunflower and cottonseed oils, which are more unsaturated, there was a clear decrease in both tocopherol concentration and oxidative stability.

The aim of this work was to evaluate antioxidant activity of lemon seeds added to soybean oil, submitted to accelerated incubator-storage test and to determine its synergistic effect with the synthetic antioxidant TBHQ. The treatments Control, TBHQ (50 mg/kg), LSE (2,400 mg/kg Lemon Seed Extract), Mixture 1 (LSE + 50 mg/kg TBHQ) and Mixture 2 (LSE + 25 mg/kg TBHQ) were prepared and subjected to the accelerated incubator-storage test at 60 ºC for 12 days; samples were taken every 3 days and analyzed regarding peroxide value and conjugated dienes. The results showed that antioxidant activity of the tested treatments were: TBHQ = Mixture 1 = Mixture 2 > LSE > Control.

This work was aimed at evaluating the antioxidant activity of rosemary extract added to soybean oil in thermoxidation conditions. Purified soybean oil, refined soybean oil and refined soybean oil containing 1,000 mg/kg rosemary extract were heated at 180 °C. The oxidation of the samples was evaluated after 0, 2.5, 5, 7.5 and 10 hours of thermoxidation by means of oxidative stability determination, total polar compounds and conjugated dienes. The purified oil differed significantly from the refined oil, mainly in relation to oxidative stability due the removal of the natural antioxidants. Rosemary extract presented antioxidant effects at high temperatures. After 10 hours of heating, 1,000 mg/kg rosemary extract added to the refined soybean oil significantly increased the oil oxidative stability from 7.52 to 13.5 hours and decreased the formation of polymers and decomposing products measured through the polar rates from 17.35 to 7.99%. The build up of primary oxidation products gauged through diene rates also decreased from 1.61 to 0.80%. Rosemary extract could be recommended as an alternative antioxidant.

The present study had the purpose of evaluating the profile of fatty acids and the total alteration of cottonseed, sunflower and palm oils brought about during discontinued frying processes of cassava frozen chips. An increase in the percentage of saturated fatty acids and a decrease in polyunsaturated fatty acids was observed, regardless of the type of oil used. With regard to the oil's global alteration, the results showed that palm oil, the most saturated one, underwent less alteration. However, none of the oils presented total polar compound values above the limits prescribed.

A utilização crescente de alimentos rápidos determinou a expansão de uma indústria de produtos fritos e pré-fritos. A compreensão das mudanças que o óleo sofre durante os processos de fritura é importante, pois pode levar à otimização destes processos, e a melhoria da qualidade do óleo de fritura e do produto final. Neste trabalho, objetivou-se determinar os níveis de alteração de diferentes óleos vegetais, girassol, soja e milho, no processo de fritura dos snacks produto cárneo empanado pré-frito congelado. As frituras foram conduzidas em temperatura de 180°C, relação superfície/volume (S/V) de 0,3 cm-1 e tempo total de aquecimento de 12 horas. Nos snacks procederam-se as análises de teor de umidade e lipídios; nos óleos as determinações de compostos polares totais, ácidos graxos livres e índice de peróxidos. Nenhuma análise apresentou alteração acima dos limites recomendados por alguns países. Desta forma, concluiu-se que as condições estabelecidas no processo de fritura são seguras, indicando que todos os óleos foram adequados à fritura, sendo o óleo de milho de maior estabilidade oxidativa.The ever growing utilization of fast food determined the expansion of an industry of pre-fried and fried products. The understanding of the changes that the oil undergoes during the frying processes is outstanding because it may lead to the optimization of such processes as well as to improvements on the quality of both frying oil and the finished product. The purpose of the present study was to determine the alteration levels of different vegetable oils, sunflower, soybean and corn, in the frying process of snacks frozen pre-fried meat coated product. The frying sessions were carried out at 180ºC temperature, 0.3 cm-1surface/volume ratio and 12 hours overall heating time. As for the snacks, the moisture rate and lipids analyses were performed; for the oils, total polar compounds, free fatty acids and peroxide indices were determined. No analysis presented any alteration above the limits recommended by some countries. Therefore, it was concluded that the conditions established in the frying process are safe, suggesting that all of the oils were fit for the frying, being the corn oil the one of the highest oxidative stability.

Objetivou-se com este estudo determinar a influência dos fatores relação superfície/volume (S/V) e tempo de fritura sobre a alteração da mistura azeite de dendê-óleo de soja em frituras descontínuas de batatas chips.Foram realizados dois procedimentos de fritura com relações S/V de 0,5 e 1,0 cm-1 e temperatura média de 180°C. O óleo foi aquecido por um período de 7,25 horas. As amostras obtidas durante o processo de fritura foram analisadas pelas determinações de índice de peróxidos, compostos polares totais, ácidos graxos livres e índice de refração. Todas as determinações analíticas foram influenciadas pelo tempo de fritura, verificando-se aumentos significativos destes parâmetros ao longo do processo de fritura. O fator relação S/V apresentou influência sobre os valores dos índices de peróxidos e de refração. A mistura azeite de dendê-óleo de soja apresentou alteração acima do limite recomendado para óleos de fritura (compostos polares totais > 25%) a partir de 6,25 horas de fritura.The purpose of this study was to determine the factors influence of surface/volume ratio (S/V) and frying time on the alteration to the "dendê" and soybean oil mixture during discontinuous frying of potatoes chips. Two frying procedures with surface/volume ratios (S/V) of 0.5 and 1.0 cm-1 at temperature of 180°C were done. The oil was heated up for 7.25 hours. Oil samples obtained during the frying process were assessed for peroxide value, total polar compounds, free fatty acids and refractive index. All analytical determinations were influenced by frying time, verifying significative increases in the values during frying process. The factor S/V ratio showed influence on the peroxide values and refractive index. "Dendê" and soybean oil mixture showed alteration above the recommended limits for frying oils (total polar compounds > 25%) after 6.25 hours of frying.

Lipid oxidation is certainly one of the most important alterations that affect both oils or fats and foods that contain them. It is responsible for the development of unpleasant taste and smell in foods, making them unsuitable for consuming. The use of antioxidants permits a longer useful life of these products. This work presents a bibliographic review of research carried out in order to evaluate the antioxidant activity of natural or synthetic substances used in the conservation of food lipid. Among such substances, the following antioxidants are highlighted: butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), tertiary butylhydroquinone (TBHQ), propyl gallate (PG), tocopherols, phenolic acids and isolated compounds from rosemary and oregano.

A finalidade deste estudo foi caracterizar os óleos extraídos das sementes de laranja, maracujá, tomate e goiaba, como aproveitamento de resíduos industriais. Os óleos foram extraídos das sementes em um extrator Soxhlet, utilizando como solvente o éter de petróleo e a caracterização dos mesmos foi realizada por meio de métodos analíticos padrões para óleos e gorduras (ácidos graxos livres, índices de peróxidos, refração, iodo, saponificação, matéria insaponificável e estabilidade oxidativa). As análises realizadas indicaram que esses óleos possuem características físico-químicas semelhantes a alguns óleos comestíveis, podendo ser uma nova fonte de óleos para o consumo humano.The purpose of this study was to characterize the extracted oils of the seeds of tomato, orange, passion fruit and guava with the objective of using industrial residues. The oils were extracted from the seeds with a Soxhlet extractor, using petroleum ether as solvent, and were characterized by standard methods for oil and fat analysis (free fatty acids, peroxide value, refractive index, iodine value, saponification value, unsaponifiable matter and oxidative stability). The analyses accomplished indicate that these oils possess similar physicochemical characteristics as some edible oils, them they can be a new source of oils for human consumption.

O presente trabalho teve como objetivo avaliar o estado de degradação do óleo de soja utilizado em frituras descontínuas. A qualidade do óleo foi monitorada durante o processo de fritura mediante análises físico-químicas como dienos conjugados (%) e ácido tiobarbitúrico - TBA (mmoles g-1) e determinação de compostos polares totais (%). Verificou-se que os valores de dienos aumentaram significativamente com o tempo e atingiram 1,87% após 15 horas para a Fritadeira I e 1,76% após 22,5 horas para a Fritadeira II. Os índices de TBA alcançaram ao final do processo, valores de 0,0265 e 0,0210 mmoles g-1 para as Fritadeiras I e II, respectivamente. As porcentagens de compostos polares totais apresentaram aumento de seis e oito vezes em relação à amostra original partindo de valores de 5,9% e 3,7% e atingindo valores de 36,8% e 29,2%, para as Fritadeiras I e II, após 15 e 22,5 horas de aquecimento, respectivamente. Assim, conclui-se que houve um aumento nas alterações do óleo de soja com o tempo de fritura, em ambas as fritadeiras. O óleo utilizado na Fritadeira I foi o que apresentou maior grau de alteração, quando comparado com o óleo da Fritadeira II, apesar do menor tempo de aquecimento. Considerando-se os limites permitidos pelas legislações de alguns países como compostos polares inferiores a 25%, os óleos das duas fritadeiras já encontravam sem condições de uso no momento do descarteThe main objective of this study was to evaluate the degree of degradation of the soybean oil used in frying processes. The quality of the oil during the frying process was evaluated by means of physical-chemical analyses, such: conjugated dienes (%) and TBA index (mmoles g-1), and determination of total polar compounds (%). It was observed that the values of conjugated dienes increasing significantly with time until 1.87% after 15 hours for fry pans I and 1.76% after 22.5 hours for fry pans II. The TBA indexes reached at the end the frying process values of 0.0265 and 0.0210 mmoles g-1 for fry pans I and II, respectively. The percentages of total polar compounds have shown an increase of six and eight times in relation to the original sample starting from 5.9% and 3.7% and reaching values of 36.8% and 29.2%, for fry pan I and II, after 15 and 22.5 hours of heating, respectively. It has been concluded that the alterations of the soybean oil increased as the time of frying increased, for both fry pans. The oil used in fry pan I showed greater alteration than the that observed in the oil used in fry pan II, in spite of the time of heating being shorter. Taking into consideration that the levels of polar compounds should be less than 25% according to the legislation of several countries, the oils used in both fry pans were already inadequate conditions at the moment of disposal.

Objetivou-se com este trabalho conhecer a influência dos tipos de óleos e tempos de fritura na perda de umidade e absorção de óleo em batatas fritas. Os experimentos foram conduzidos com frituras de batatas empregando óleos de girassol, milho e soja, submetidos em diferentes tempos, à temperatura de 175ºC. Amostras de batatas fritas foram analisadas por meio das determinações de umidade e teor lipídico, após primeira, quinta, décima e décima-quinta fritura. Análise de variância e teste de Tukey foram aplicados aos dados experimentais a níveis de 1 e 5% de significância. Verificou-se que batatas quando fritas em óleo de soja absorveram menor quantidade de óleo, diferindo significativamente daquelas fritas nos demais óleos estudados, além de ter obtido maior teor de umidade ao longo de todo o processo. No entanto, para o teor lipídico, batatas fritas em óleos de girassol e milho não diferiram significativamente entre si.The objective of this study was to determine the influence of the oil type and the frying time on oil absorption and moisture loss by potato chips. Sliced potatoes were fried in sunflower, corn or soybean oils, at 175ºC, for 10 minutes and different times. Samples of potatoes were analyzed for moisture and lipid contents after 1, 5, 10 and 15 fryings. Analysis of variance and Tukey test were applied to the experimental data at 1 and 5% level of significance. It was verified that the soybean oil resulted in smaller absorption by the potatoes, in comparison with the other oils studied, and higher moisture contents in the fried potatoes. Regarding lipid contents, potato chips fried in sunflower and corn oils didn't differ significantly.

Este trabajo tuvo como objetivo caracterizar las semillas de jabuticaba (Myrciaria cauliflora Berg) en cuanto a su composición proximal y potencial antioxidante y evaluar el perfil de ácidos grasos en el aceite extraído de las mismas. Para la obtención del extracto, las semillas deshidratadas y trituradas fueron extraídas con alcohol etílico por 30 minutos, en la proporción de 1:3 de semillas:alcohol etílico, bajo agitación continua, a temperatura ambiente. Seguidamente, la mezcla fue filtrada y el sobrenadante fue deshidratado a 40oC con la finalidad de determinar, por pesaje directo, el rendimiento en materia seca del extracto. De acuerdo con los resultados obtenidos, las semillas de jabuticaba mostraron ser una importante fuente de carbohidratos totales, además presentaron una relevante actividad antioxidante. El aceite de jabuticaba presentó porcentaje significativa de ácidos grasos poliinsaturados, con predominancia del ácido linoleico y α-linolénico, ácidos grasos esenciales.

RESUMO Este trabalho teve como principais objetivos medir o teor de compostos fenólicos totais e a atividade antioxidante do extrato de Portulaca oleracea L., além de avaliar a estabilidade oxidativa e a retenção dos compostos fitoquímicos presentes no óleo de soja adicionado de antioxidantes sintéticos (TBHQ e BHT) e naturais (Extrato de Portulaca oleracea L.). Os tratamentos: óleo de soja (OS), óleo de soja adicionado de 100 mg/kg TBHQ (TBHQ), óleo de soja adicionado de 100 mg/kg BHT (BHT) e óleo de soja adicionado de 100 mg/kg extrato (Extrato) foram submetidos à termoxidação a 180 oC, por cinco horas. O extrato apresentou 99,5 mg EAG/100 g de compostos fenólicos totais e 84,6%, 35,5% e 1,8 µM Trolox/100 g de atividade antioxidante para DPPH, sistema β-caroteno/ácido linoleico e FRAP, respectivamente. A estabilidade oxidativa do tratamento Extrato foi inferior à do TBHQ, que apresentou o maior período de indução (7,6 h). Após aquecimento, os tratamentos TBHQ e Extrato apresentaram maior capacidade de retenção de tocoferóis e fitosteróis, atingindo valores acima de 88 e 87%, respectivamente. Percentagens similares de ácidos graxos poli-insaturados foram encontradas nos tratamentos OS e Extrato. O extrato de beldroega na concentração 100 mg/kg foi capaz de reduzir as alterações sofridas pelo óleo de soja após aquecimento e pode ser utilizado como substituto natural de antioxidantes sintéticos.

Abstract The present study aims to evaluate the influence of extraction methods on the quality of bioactive compounds and antioxidant capacity in Pterodon emarginatusVogel (sucupira) oils. The oils were extracted from the sucupira seeds by Soxhlet and by the extraction system of Bligh & Dyer. The oils were analyzed as to fatty acid profile, tocopherols, phytosterols, carotenoids, total phenolics, and total antioxidant capacity. The extraction by Soxhlet showed better yield of total lipids and was more efficient to extract tocopherols, phytosterols, and carotenoids, besides presenting better antioxidant activity by DPPH•. However, this method showed insufficient capacity to extract the polar lipid components of the sample, as evidenced by the low results of total phenolic compounds. On the other hand, the Bligh & Dyer method preserved the fatty acid profile and was also effective to extract higher phenolic compounds content and presented superior antioxidant activity when assessed by FRAP, ABTS•+, and oxidative stability index.

Abstract Each year, the consumption of vegetable oils increases gradually. Some oils, such as chia, sesame, and quinoa, are consumed due to the nutritional properties and health promoters that have been recognized in their components. Based on this premise, the present study aimed to characterize chia (Salvia hispanica), sesame (Sesamum inducum), and quinoa (Chenopodium quinoa) oils, in order to enable their applications in the development of new food products. Chia oil presented higher degradation, as it stood out with higher amounts of free fatty acids (4.46%) and peroxide value (18.35 meq/kg). It is an oil that is rich in polyunsaturated fatty acids (75.47%), and, consequently, with high refractive index (1,475) and iodine value (192.86 g/100 g). Quinoa oil stood out for its higher oxidative stability (17.55 h) and higher amount of phenolic compounds (190.84 mg/100 g). Sesame and quinoa oils showed no significant difference for carotenoids, but sesame oil had higher content of total tocopherols (656.50 mg/kg). Thus, the oils can be used in technological processes and/ or in the formulation of new food products, in order to their increase the nutritional value.