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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

Antioxidant activity in cooked and gastrointestinal enzyme digested eggs

Remanan, Mejo Kuzhithariel Unknown Date
No description available.
2

Desenvolvimento e atividade do fitocosmético contendo licopeno para o combate à aceleração do envelhecimento cutâneo /

Cefali, Letícia Caramori. January 2009 (has links)
Resumo: O licopeno é um carotenóide com poderosa ação antioxidante, encontrado em maior quantidade no tomate, utilizado no combate a inúmeras doenças como vários tipos de câncer, dentre eles o de próstata, e doenças cardiovasculares. Sua ação tópica é pouco explorada e, por isso, a proposta de ser utilizado no combate à aceleração do envelhecimento cutâneo, incorporado em uma emulsão. Um estudo preliminar foi realizado para a escolha do tipo de tomate que apresenta maior concentração de licopeno e/ou maior atividade antioxidante. O método de quantificação do fitoquímico foi validado e, em função dos testes de avaliação antioxidante in vitro, o tomate do tipo salada foi o escolhido para o desenvolvimento do fitocosmético. Além disso, o extrato foi submetido à avaliação da citotoxicidade in vitro que constatou a não ocorrência de toxicidade em fibroblastos e macrófagos. Assim, o cosmético foi desenvolvido contendo fase oleosa constituída de derivados de karité e submetido a testes para avaliar sua estabilidade, identificar as características da emulsão, avaliar seu comportamento reológico e sua atividade cosmética pelos testes de permeação cutânea e verificando a eficácia quanto à ação antioxidante do licopeno incorporado na emulsão. Foi possível observar que o fitocosmético é estável, de acordo com as condições experimentais realizadas neste estudo, permite a retenção do licopeno na epiderme e na derme e apresenta atividade antioxidante, sendo promissor para o combate à aceleração do envelhecimento cutâneo. / Abstract: Lycopene, a carotenoid with high antioxidant activity, is found in greater quantities in tomatoes used to combat many diseases such as various types of cancers, including of the prostate, and cardiovascular diseases. Its topical action is not explored and therefore the proposal to be used to combat aging, incorporated into an emulsion. A preliminary study was conducted to evaluate which tomato had higher concentration of lycopene and/or higher antioxidant activity. The method of quantification of the phytochemical was validated and the lycopene extract was evaluated by testing in vitro antioxidant activity. Tomato salad was chosen for the development of the phytocosmetic. Furthermore, this extract was subjected to the evaluation of cytotoxicity in vitro activity and it was found that the non-occurrence of toxicity in fibroblasts and macrophages. Thus was developed a product containing oily phase consists only derived about shea which was submitted to tests to assess its stability, to identify the characteristics of the emulsion, to evaluate the rheological behavior and cosmetic activity carried out tests such as skin permeation and checking the effectiveness in the antioxidant action of lycopene incorporated into emulsion. Through the results it was possible to observe that the phytocosmetic is stable, allows the retention of lycopene in the epidermis and dermis, shows antioxidant activity and it's promising to combat the acceleration of skin aging / Orientador: Vera Lucia Borges Isaac / Coorientador: Hérida Regina Nunes Salgado / Banca: Marcos Antônio Correa / Banca: Pedro Alves da Rocha Filho / Mestre
3

Enhancing antioxidant activity and extractability of bioactive compounds of wheat bran using thermal treatments

Dona, Arshala Madapathage 11 April 2011 (has links)
Wheat bran contains a diverse collection of macronutrients, micronutrients and bioactive components, including those thought to have an important role in reducing the risk of many chronic diseases. The complication of wheat bran as a functional food relates to its high insoluble fibre content, which renders bran and its constituent bioactives largely indigestible, and hence with limited bioavailability. The main objective of this thesis research was to evaluate the effects of heat treatments of branon the antioxidant activity and chemical composition of the bran. Presumably, if the solubility of wheat bran can be enhanced by pre-treatment, its biological impact associated with its fibre and resident phytochemicals would also be enhanced. Compared to untreated bran, freeze dried water soluble extracts of thermally treated bran had substantially enhanced levels of antioxidant activity and signficantly increased concentration of a very broad spectrum of bran bioactive constituents including phenolics, minerals, phytate, B vitamins, and non-starch polysaccharide fibre compounds. Results taken together point to the development of novel wheat bran and extracts with considerable commercial potential for whole grain food use and a variety of nutraceutical applications far beyond what may be possible with whole grain wheat or normal bran. Outcomes of the research highlight the conclusion that the nutritional and functional food benefits of normal wheat bran probably represent a fraction of its potential due to the limited digestibility of wheat bran, which in turn, limits the bioavailability of its fiber and constituent bioactive compounds.
4

Enhancing antioxidant activity and extractability of bioactive compounds of wheat bran using thermal treatments

Dona, Arshala Madapathage 11 April 2011 (has links)
Wheat bran contains a diverse collection of macronutrients, micronutrients and bioactive components, including those thought to have an important role in reducing the risk of many chronic diseases. The complication of wheat bran as a functional food relates to its high insoluble fibre content, which renders bran and its constituent bioactives largely indigestible, and hence with limited bioavailability. The main objective of this thesis research was to evaluate the effects of heat treatments of branon the antioxidant activity and chemical composition of the bran. Presumably, if the solubility of wheat bran can be enhanced by pre-treatment, its biological impact associated with its fibre and resident phytochemicals would also be enhanced. Compared to untreated bran, freeze dried water soluble extracts of thermally treated bran had substantially enhanced levels of antioxidant activity and signficantly increased concentration of a very broad spectrum of bran bioactive constituents including phenolics, minerals, phytate, B vitamins, and non-starch polysaccharide fibre compounds. Results taken together point to the development of novel wheat bran and extracts with considerable commercial potential for whole grain food use and a variety of nutraceutical applications far beyond what may be possible with whole grain wheat or normal bran. Outcomes of the research highlight the conclusion that the nutritional and functional food benefits of normal wheat bran probably represent a fraction of its potential due to the limited digestibility of wheat bran, which in turn, limits the bioavailability of its fiber and constituent bioactive compounds.
5

Desenvolvimento e atividade do fitocosmético contendo licopeno para o combate à aceleração do envelhecimento cutâneo

Cefali, Letícia Caramori [UNESP] 25 November 2009 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:24:06Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-11-25Bitstream added on 2014-06-13T20:11:56Z : No. of bitstreams: 1 cefali_lc_me_arafcf.pdf: 635100 bytes, checksum: 20424d01dd8e9cc7f5c20d87bb20eec3 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / O licopeno é um carotenóide com poderosa ação antioxidante, encontrado em maior quantidade no tomate, utilizado no combate a inúmeras doenças como vários tipos de câncer, dentre eles o de próstata, e doenças cardiovasculares. Sua ação tópica é pouco explorada e, por isso, a proposta de ser utilizado no combate à aceleração do envelhecimento cutâneo, incorporado em uma emulsão. Um estudo preliminar foi realizado para a escolha do tipo de tomate que apresenta maior concentração de licopeno e/ou maior atividade antioxidante. O método de quantificação do fitoquímico foi validado e, em função dos testes de avaliação antioxidante in vitro, o tomate do tipo salada foi o escolhido para o desenvolvimento do fitocosmético. Além disso, o extrato foi submetido à avaliação da citotoxicidade in vitro que constatou a não ocorrência de toxicidade em fibroblastos e macrófagos. Assim, o cosmético foi desenvolvido contendo fase oleosa constituída de derivados de karité e submetido a testes para avaliar sua estabilidade, identificar as características da emulsão, avaliar seu comportamento reológico e sua atividade cosmética pelos testes de permeação cutânea e verificando a eficácia quanto à ação antioxidante do licopeno incorporado na emulsão. Foi possível observar que o fitocosmético é estável, de acordo com as condições experimentais realizadas neste estudo, permite a retenção do licopeno na epiderme e na derme e apresenta atividade antioxidante, sendo promissor para o combate à aceleração do envelhecimento cutâneo. / Lycopene, a carotenoid with high antioxidant activity, is found in greater quantities in tomatoes used to combat many diseases such as various types of cancers, including of the prostate, and cardiovascular diseases. Its topical action is not explored and therefore the proposal to be used to combat aging, incorporated into an emulsion. A preliminary study was conducted to evaluate which tomato had higher concentration of lycopene and/or higher antioxidant activity. The method of quantification of the phytochemical was validated and the lycopene extract was evaluated by testing in vitro antioxidant activity. Tomato salad was chosen for the development of the phytocosmetic. Furthermore, this extract was subjected to the evaluation of cytotoxicity in vitro activity and it was found that the non-occurrence of toxicity in fibroblasts and macrophages. Thus was developed a product containing oily phase consists only derived about shea which was submitted to tests to assess its stability, to identify the characteristics of the emulsion, to evaluate the rheological behavior and cosmetic activity carried out tests such as skin permeation and checking the effectiveness in the antioxidant action of lycopene incorporated into emulsion. Through the results it was possible to observe that the phytocosmetic is stable, allows the retention of lycopene in the epidermis and dermis, shows antioxidant activity and it’s promising to combat the acceleration of skin aging
6

Morpho-pomological and chemical properties of pomegranate (Punica granatum L.) cultivars in Iran

Rahimi, Ali Mohammad, Jafarpour, Mehrdad, Pessarakli, Mohammad 25 January 2017 (has links)
This study was conducted to investigate the physico-chemical properties and antioxidant activity of five pomegranates fruit (Punica granatum L.) cultivars grown in Iran. Significant differences were found among the pomegranate cultivars for many of the properties studied. Results showed that, in particular, fruit diameter ranged from 63.63 mm (Syah) to 79.29 mm (Rabab), fruit volume from 153.3 cm3 (Syah) to 293.3 cm3 (Rabab), fruit density from 0.93 g cm-3 (Rabab) to 1.13 g cm-3 (Torsh Sefeed). Although Syah showed the lowest fruit weight (144.8 g), fruit yield (8.28 ton ha–1) and fruit skin thickness (1.55 mm), Rabab had the highest fruit yield (27.1 ton ha–1) and fruit skin thickness (2.32 mm). Juice volume was between 61.1 and 67.0 cm3. Percent of aril ranged from 59.64% (Rabab) to 75.3% (Syah) and weight of aril was between 108.9 and 199.8 g. Also, results indicated that titratable acidity content varied from 0.39% (Syah) to 1.13% (Torsh Sefeed). The total soluble solids content varied from 12.67 ◦Brix (Torsh Sefeed) to 15.67 ◦Brix (Zardeh Anar), pH values from 3.05 to 3.77, Electrical conductivity values from 2.8 to 3.14 dSm-1 and vitamin C content from 59.25 to 69.52 mg 100g1. The anthocyanins content was observed between 80.36 (Syah) and 216.97 (Zardeh Anar). The antioxidant activity of pomegranate cultivars ranged from 27.24% (Syah) to 84.04% (Torsh Sefeed). These results demonstrated that the cultivar was the major factor which influences the morpho-pomological and chemical (especially, antioxidant activity), properties in pomegranates.
7

Stanovení biologicky aktivních látek ve vybraných přírodních rostlinných extraktech / Analysis of some biologicaly active components in natural plant extracts

Kováčová, Ivana January 2016 (has links)
This thesis is focused on the study of the effectiveness of active ingredients from natural extracts such as milk thistle and turmeric. The thesis describes the use of modern methods of analysis and identification of active substances located in plants of milk thistle and turmeric. In the experimental part of thesis, which was preceded by a literature search focused on the biological effects of active substances in the chosen natural extracts, the extracts were characterized according to group characteristics (total assessment of polyphenols and flavonoids, assessment of antioxidant activity, and assessment of vitamin C volume and tocopherol). The next part is focused on the study of the encapsulation of natural active substances into the organic particles: liposomes. Silymarin and curcumin were encapsulated as active substances. The idea of a plant with a single active ingredient is usually erroneous. Plants usually contain hundreds of components which cooperate on a given effect. Therefore, the majority of herbalists believe that a simple plant is an active ingredient. However, some plants are known to be containing a particular active phytochemical. For instance, plants such as the milk thistle, turmeric, or a ginkgo are great examples of the plant containing a particular active phytochemical. In these cases, the active compound is disproportionately more effective than the plant itself. Encapsulation efficiency of active ingredients of Silymarin and curcumin was determined by HPLC/PDA. The aim of the analysis was to observe the behavior of elements during the incubation in surrounding of gastric juice model, and the stability while maintaining the particles in model food.
8

Avaliação dos compostos fenólicos e das propriedades antioxidantes da polpa do pequi (Caryocar spp) processado e in natura / Evaluation of phenolic compounds and antioxidant properties of pulp pequi (Caryocar spp) processed and fresh

Oliveira, Lucillia Rabelo de 14 July 2010 (has links)
O pequi caracteriza-se por possuir expressiva quantidade de compostos fenólicos, que por apresentarem propriedades antioxidantes estão associados com a prevenção da formação de radicais livres. Além de ser consumido in natura, é também comumente consumido na forma processada. No entanto, sabe-se que os antioxidantes presentes nos vegetais podem ser afetados pela forma de processamento e provocam alterações dos teores de fenólicos totais (FT) bem como da sua atividade antioxidante. Este trabalho objetivou avaliar o teor de FT e as propriedades antioxidantes da polpa do pequi processado e in natura. Foram obtidos os extratos alcoólicos (EALC) e aquosos (EAQ), a partir de amostras liofilizadas de diversas polpas de pequi processado (em conserva) e também do in natura, bem como as frações de ácidos fenólicos livres (AFL), ésteres solúveis de ácidos fenólicos (AFS) e ésteres insolúveis de ácidos fenólicos (AFI) de pequi processado (CB1). Os EALC e EAQ, além dos líquidos provenientes das conservas (LC), foram avaliados quanto aos teores de FT, onde se verificou que os EAQ do pequi in natura, principalmente, e do processado tiveram um maior conteúdo de FT quando comparados aos EALC. Os LC, por sua vez, apresentaram valores médios ainda maiores que os EAQ. Com relação ao teor de FT das frações, a AFL se destacou diante da AFS e AFI. Os extratos, LC e frações foram avaliados quanto à atividade antioxidante in vitro pelo sistema β-caroteno/ácido linoléico e também pelo ensaio do radical DPPH• (2,2 difenil-1-picril-hidrazila). No primeiro, verificou-se que os EAQ e LC do pequi apresentaram maior atividade que os EALC. Foi observada ainda atividade elevada em todas as frações analisadas. No segundo ensaio pelo método do radical DPPH•, pode-se observar que os extratos aquosos do pequi in natura apresentaram maior atividade, enquanto que, no pequi processado, os extratos alcoólicos e os líquidos das conservas tiveram melhores resultados. Verificou-se também que a AFL possui atividade superior às outras frações. De uma maneira geral, os resultados do pequi processado foram inferiores aos do pequi in natura tanto em relação aos teores de FT como na atividade antioxidante. Verificando-se ainda, que isto se deve principalmente à perda dos FT da polpa, indicando que houve lixiviação destes compostos para os LC. / Pequi characterized by having a significant amount of phenolic compounds, that are related with its antioxidant properties that are associated with the prevention of free radicals. Besides being eaten fresh, it is also widely consumed in processed form. However, it is known that the antioxidants present in plants can be affected by processing form and cause changes in the levels of total phenolic content (FT) and the antioxidant activity. The objective of this study was to evaluate the content of phenolic compounds and the antioxidant properties of the pequi pulp processed and fresh. Were obtained the alcoholic (EALC) and aqueous (EAQ) extracts from lyophilized samples of various pulps pequi processed (canned) and also in nature, as well as the fractions of free phenolic acids (AFL), soluble esters of phenolic acids (AFS) and insoluble esters of phenolic acids (AFI) of processed pequi (CB1). The EALC and EAq, besides the liquid from the canned (LC) were evaluated for the levels of FT, where it was found that the EAQ of the pequi in nature, mainly, and of the processed had, in general, a higher content of FT compared to EALC. The LC, in turn have showed that even greater EAQ. Regarding the content of FT of the fractions, the AFL stood in front of the AFS and AFI. The extracts, LC and fractions were also evaluated for their antioxidant activity in vitro by the system β-caroteno/ linoleic acid and by test DPPH• (2,2-diphenyl-1-picryl hydrazyl). At first, it was found that the LC and EAQ of the pequi showed greater activity than the EALC. Still high activity was observed in all fractions analyzed. In the second test, we can observe that the EAQ of the pequi in nature showed greater activity, whereas in pequi processed, the EALC and LC had better results. It was also noted that the AFL has superior activity to other fractions. In general, the results of pequi processed were lower than in fresh pequi both in relation to content of FT as antioxidant activity. Verifying also, that this is mainly due to the loss of FT of the pulp, indicating that there was leaching of these compounds to the LC.
9

Efeito da sazonalidade no perfil químico e na atividade antioxidante de Baccharis dracunculifolia (Asteraceae) e ação modulatória desta planta sobre o metabolismo oxidativo de neutrófilos / Effect of the seasonality in the chemical profile and in the antioxidant activity of Baccharis dracunculifolia (Asteraceae) and modulatory action of this plant on the neutrophils oxidative metabolism

Figueiredo, Andréa Silva Garcia de 14 May 2010 (has links)
Os neutrófilos ou leucócitos polimorfonucleares (PMNs) são células fagocíticas com funções bactericida e fungicida altamente potentes. A destruição dos microrganismos invasores é realizada através da liberação de substâncias tóxicas presentes em seus grânulos e das espécies reativas de oxigênio (EROs) produzidas durante o metabolismo oxidativo dessas células. Apesar dos benefícios da atividade antimicrobiana, em situações de intensa ativação celular, a grande produção e liberação de compostos citotóxicos podem causar efeitos deletérios sobre os tecidos do hospedeiro, como parece ocorrer em doenças por imunocomplexos. O grande potencial dos antioxidantes para o tratamento e prevenção dessas doenças tem levado à pesquisa de novos compostos que atuam no processo inflamatório em que estão envolvidos os neutrófilos ativados. Dentre estes, destacam-se os naturais, em que se encontra a planta Baccharis dracunculifolia (Asteraceae), principal fonte botânica da própolis verde, sendo que a própolis possui diversas atividades biológicas conhecidas. Entretanto, a produção de metabólitos secundários pelas plantas pode ser modificada de acordo com fatores sazonais o que dificulta os estudos e pode acarretar em alterações de atividade biológica. Desta forma, este trabalho avaliou o efeito da sazonalidade no perfil químico de B. dracunculifolia e na atividade desta planta sobre o metabolismo oxidativo de PMNs. Para isso, extratos etanólicos brutos das folhas de B. dracunculifolia (EEBBd), colhidas mensalmente durante 14 meses foram submetidos à ensaios de cromatografia líquida de alta eficiência (CLAE), e avaliados quanto à capacidade de inibir a quimioluminescência dependente de luminol (QLlum) e de lucigenina (QLluc) produzida por PMNs estimulados. Além disso, para desvendar o(s) possível(is) mecanismo(s) de ação responsável(is) pela atividade antioxidante, foram realizados, com a amostra mais ativa em inibir a QL, ensaios para avaliar a citotoxicidade, a atividade scavenger de radicais livres (DPPH) e a ação sobre a atividade da enzima NADPH oxidase. Os resultados mostraram que todos os EEBBd inibiram tanto a QLlum quanto a QLluc de forma dependente da concentração e que para ambos os ensaios houve variação na eficiência deste efeito biológico ao longo do período de tempo estudado, demonstrando que a sazonalidade desempenhou um papel importante na intensidade da atividade antioxidante dos extratos. O ensaio de CLAE permitiu análise dos seguintes compostos: ácido caféico, ácido p-cumárico, aromadendrina-4-metil éter, isosakuranetina e artepilin C, e revelaram que apesar de não haver notória variação qualitativa entre os componentes, foi observada grande diferença quantitativa. As análises com a amostra do mês de maior atividade antioxidante (Maio/07) revelou que esta foi colhida durante um período de baixo índice pluviométrico, temperaturas amenas e apresentou a menor concentração da maioria dos compostos fenólicos estudados, evidenciando que tais compostos não foram os maiores responsáveis pela atividade biológica da amostra e que alguns desses compostos podem ter atuado como pró-oxidantes. Além disso, foi verificado que esta amostra atuou de forma não tóxica sobre as células, através da captação de parte das EROs geradas no meio reacional e de inibição parcial da atividade da NADPH oxidase. / Neutrophils or polymorphonuclear (PMN) are phagocytic cells with potent bactericidal and fungicidal functions. The destruction of invading microorganisms is made by the release of toxic substances contained within their granules and by the reactive oxygen species (ROS) produced during the oxidative metabolism of these cells. Despite the benefits of antimicrobial activity, in situations of intense cellular activation, large production and release of toxic compounds may cause deleterious effects on host tissue, as it seems to occur in immune complex diseases. The great potential of the antioxidants for the treatment and prevention of these diseases has led to the search of new compounds that act in the inflammatory process where are involved the activated neutrophils. Within this context, natural products are highlighted, mainly plants, among which is the Baccharis dracunculifolia (Asteraceae), the main botanical source of green propolis, which has several activities already known. However, secondary metabolites of plants can be modified according to seasonal factors, what can difficult the studies and alter the biological activity results. Thus, this study evaluated the effect of seasonality in the chemical profile of B. dracunculifolia and in the activity of this plant on the oxidative metabolism of PMNs. For this, crude ethanolic extracts of B. dracunculifolia leaves (CEEBd), harvested monthly for 14 months were analyzed in high performance liquid chromatography (HPLC) and evaluated for their ability to inhibit the luminol- and lucigenin-dependent chemiluminescence (CLlum and CLluc, respectively) produced by stimulated PMNs. In addiction, to understand the possible mechanisms of action responsible for antioxidant effect, the most active sample in the CL test was evaluated for the following proprieties: cytotoxic, scavenger of free radicals (DPPH) and action on the NADPH oxidase activity. The results showed that all CEEBd inhibited both CLlum and CLluc in a concentration-dependent manner and that in both trials it was found variation in the biological effect over the study period, indicating that the seasonality played an important role on the intensity of the antioxidant activity of the extracts. The HPLC assay allowed the analysis of the following compounds: caffeic acid, p-coumaric acid, aromadendrin-4\'-methyl ether, isosakuranetin and artepillin C, and showed that although there was no evident variation in qualitative profile, it was observed large quantitative differences. The analysis of the sample of greatest antioxidant activity (May/07) revealed that it was harvested during a period of low rainfall, mild temperatures and had lower concentrations of most compounds studied, indicating that these compounds were not the most responsible for the biological activity of the sample and that some of these substances may have acted as pro-oxidants molecules. Furthermore, it was found that this sample works in a non-toxic manner on cells, by capturing some of the ROS generated in the reaction medium and by partial inhibition of NADPH oxidase activity.
10

Reciclagem de resíduos do processamento de tilápia (Oreochromis niloticus) visando obter hidrolisado proteico como coproduto / Tilapia (Oreochromis niloticus) processing residues recycling to obtain protein hydrolysates as coproduct

Lunelli, Taciana 08 October 2015 (has links)
O crescimento da produção e comercialização de pescado gera um aumento considerável na quantidade de resíduos. A escassez de reutilização e as formas incorretas de descarte tem sido preocupação constante das indústrias e dos pesquisadores, que buscam soluções para a melhor destinação dos mesmos. Buscando o conceito de empresa eco eficiente, são propostos tratamentos que levem à obtenção de coprodutos. A produção de \"farinha de peixe\" é a forma de aproveitamento do resíduo mais utilizada, porém apresenta baixo valor comercial. A elaboração de hidrolisados proteicos apresenta-se como uma alternativa de maior valor agregado. A clivagem proteica realizada por enzimas específicas pode gerar peptídeos biologicamente ativos, que apresentam propriedades funcionais e medicinais, bem como atividade antioxidante. O objetivo deste trabalho foi a elaboração e caracterização de hidrolisados proteicos de cabeças de tilápia (Oreochromis niloticus), a aferição da atividade antioxidante destes e sua relação com o tamanho de peptídeos, como forma de se obter e disponibilizar coprodutos, visando a sustentabilidade da cadeia produtiva desta espécie. O hidrolisado proteico de tilápia (HPT) foi obtido por hidrólise enzimática e empregando as enzimas Neutrase (Protemax NP-800), Papaína (Brauzyn-100) e Pepsina nos tempos 30, 60 e 120 minutos. O grau de hidrólise foi determinado através da metodologia com utilização do o-ftaldialdeído. A atividade antioxidante foi avaliada pelos ensaios do DPPH e ABTS+. O perfil de peptídeos foi avaliado através da separação por cromatografia em gel com coluna Superdex peptide. O grau de hidrólise para os tratamentos com a neutrase (30 min, 60 min, 120min) variou de 11,3% a 14,1%. No tratamento com a papaína (30 min, 60 min, 120 min) o grau de hidrólise foi superior ao observado com a enzima neutrase, apresentando variação de 21,14%a 25,28%. A variação para o tratamento com a pepsina (30 min, 60 min e 120 min) foi de 10,18% a 14,97% Todos os hidrolisados apresentaram propriedade antioxidante através da inibição de radicais livres, mesmo a concentrações baixas de hidrolisado. A inibição de 50% (EC50) dos radicais na metodologia de DPPH ocorreu com concentrações inferiores a 3mg/mL para todos os tratamentos, sendo a menor concentração 1,36 mg/mL (pepsina 120 min) e a maior 2,70 mg/mL (neutrase 30 min). Na metodologia de ABTS, concentrações superiores foram necessárias para a inibição de 50% dos radicais, porém ainda assim foram inferiores a 5%. A menor concentração foi 3,58 mg/mL (pepsina 120 min) e a maior foi de 4,49 mg/mL (neutrase 60 min). O tamanho das cadeias de peptídeos para a maioria dos tratamentos se situou entre cadeias de 1000 a 10000Da, sendo que o tratamento com pepsina promoveu porcentagem de peptídeos com maior peso molecular seguido pela neutrase. A papaína foi a enzima que promoveu maior clivagem de proteína e menores tamanhos de peptídeos, localizados na faixa de 100 a 1000 Da, valor relacionado ao seu maior grau de hidrólise. As propriedades observadas nos hidrolisados elaborados indicam que este pode ser um potencial suplemento alimentício devido ao seu elevado valor proteico, aditivos para conservação de alimentos e ainda aplicados na indústria farmacêutica. / The growth in production and marketing of fish generates a considerable increase in the amount of waste. The scarcity of re-used products and incorrect disposal forms has been a constant concern of industries and researchers who seek solutions for better allocation thereof. Seeking an efficient eco company concept, proposed treatments are leading to obtaining co-products. The production of \"fish meal\" with the residues is the most common use for the waste, but has a low commercial value. The preparation of protein hydrolysates is presented as an alternative with higher added value. The protein cleavage performed by specific enzymes can generate biologically active peptides which exhibit functional and medicinal properties as well as antioxidant activity. The objective of this work was the preparation and characterization of protein hydrolysates of tilapia (Oreochromis niloticus) , the measurement of antioxidant activity of these and its relation to the size of peptides as a way to obtain and provide co-products , aimed at the sustainability of the chain production of this species. The protein hydrolyzate of tilapia (HPT) was obtained by enzymatic hydrolysis and employing the enzyme Neutrase (Protemax NP- 800), Papain (Brauzyn - 100) and Pepsin at 30, 60 and 120 minutes. The degree of hydrolysis was determined using o- phthaldialdehyde . In the treatment with papain (30 min, 60 min, 120 min) the degree of hydrolysis was higher than that observed with Neutrase enzyme, showing variation of 21.14% to 25.28%. The variation for treatment with pepsin (30 min, 60 min and 120 min) was 10.18% and 14.97% hydrolyzed. All samples showed antioxidant properties through inhibition of free radicals, even at low concentrations hydrolyzate. The 50% inhibition (EC50) of the DPPH radical methodology occurred at concentrations below 3 mg / ml for all treatments, being the lowest concentration 1.36 mg / ml (lot 120 min) and the largest 2.70 mg / ml (Neutrase 30 min). In the ABTS method, higher concentrations were required for 50% inhibition of the radical, but still was less than 5%. The lowest concentration was 3.58 mg / mL (120 pepsin min) and the largest was 4.49 mg / mL (Neutrase 60 min). The size of the peptide chains to most treatments ranged from 1000 to 10000Da chains, whereas treatment with pepsin promoted percentage of peptides of higher molecular weight followed by Neutrase. The papain was the enzyme cleavage that generated more protein and peptides of smaller size, situated in the range from 100 to 1000 Da, which is related to the higher degree of hydrolysis. The properties observed in hydrolysates produced indicate that this is a potential food supplement because of its high protein value for food preservation additives, and applied in the pharmaceutical industry.

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