Alessandro de Lima

Caracterização nutricional e compostos antioxidantes em resíduos de polpas de frutas tropicais

O Brasil e um dos paises que mais produz residuos agroindustriais, como os residuos de frutas pelas industrias de polpas, o que tem contribuido para o aumento da producao do lixo orgânico, provocando graves problemas ambientais. Nesse contexto, estudos tem sido conduzidos com o intuito de investigar o valor nutricional desses residuos, valorizando-os e sugerindo novas alternativas de utilizacao. Assim, neste trabalho, objetivou-se realizar a caracterizacao nutricional e determinar os compostos antioxidantes dos residuos de polpas de frutas tropicais: acerola (Malpighia glabra L.), goiaba (Psidium Guayaba L.), abacaxi (Ananas comosus L.), cupuacu (Theobroma grandiflorum), bacuri (Platonia insignis) e graviola (Annona muricata L.). Os resultados encontrados mostraram que os residuos analisados apresentaram quantidades significativas de macronutrientes (carboidratos, proteinas e lipidios). Todos os residuos avaliados, com excecao do cupuacu, apresentaram valores elevados de vitamina C. Quanto aos carotenoides, destacou-se o residuo de acerola com 881,56 ± 9,01 µg/100 g e o residuo de goiaba, com 644,9 ± 10,02 µg/100 g. Os residuos analisados apresentaram baixas concentracoes de antocianinas e flavonoides. Com relacao aos teores de fenolicos totais se destacou o residuo da polpa de acerola com 247,62 ± 2,08 mg/100 g. Portanto, pode-se concluir que os residuos de polpas de frutas empregados neste estudo sao fontes potenciais de macronutrientes e compostos bioativos, destacando-se os residuos de acerola e goiaba como mais ricos em compostos antioxidantes.

Chemical composition and bioactive compounds of grape pomace (Vitis vinifera L.), Benitaka variety, grown in the semiarid region of Northeast Brazil

Grape pomace (Vitis vinifera L.), Benitaka variety, grown in the semiarid region of Northeast Brazil was evaluated in relation to chemical composition, and content of minerals and functional properties. Its microbiological quality and toxic potential, using Artemia salina sp, were also investigated. The results showed that the flour obtained from these residues had below neutral pH (3.82), moisture (3.33g/100g), acidity of (0.64g of citric acid/100g), and ash (4.65 g/100g). The amount of total dietary fiber (46.17g/100g) stood out quantitatively compared to the content of carbohydrate (29.2g/100 g), protein (8.49g/100g), and lipids (8.16g/100g). The total energy was 224Kcal/100g. With regard to the compounds with functional properties, higher values of insoluble fiber 79% (36.4 g/100 g); vitamin C (26.25 mg of acid ascorbic/100g), and anthocyanins (131mg/100g) were found. The minerals iron, potassium, zinc, manganese, and calcium were present in higher concentrations. There were no significant copper values. The results showed that the grape residues are an important source of nutrients and compounds with functional properties suggesting that they can be incorporated as an ingredient in the diet and/or used as a dietary supplement aiming at health benefits. The residues did not show microbiological contamination and were considered nontoxic.

Avaliação da atividade antioxidante e identificação dos ácidos fenólicos presentes no bagaço de maçã cv. Gala

Recebido para publicacao em 7/10/2007 Aceito para publicacao em 7/4/2008 (002911) 1 Programa de Pos-Graduacao em Ciencia dos Alimentos, Ciencia e Tecnologia de Alimentos – CAL, Centro de Ciencias Agrarias – CCA, Universidade Federal de Santa Catarina – UFSC, Rod. Admar Gonzaga, 1346, Itacorubi, CP 476, CEP 88934-001, Florianopolis SC, Brasil 2 Departamento de Alimentos e Nutricao Experimental, Faculdade de Ciencias Farmaceuticas, Universidade de Sao Paulo – USP, Av. Prof. Lineu Prestes, 580, Bloco 14, CEP 05508-900, Sao Paulo SP, Brasil, E-mail: jmancini@usp.br *A quem a correspondencia deve ser enviada Avaliacao da atividade antioxidante e identificacao dos acidos fenolicos presentes no bagaco de maca cv. Gala

Identification of Phenolic Compounds and Evaluation of Antioxidant and Antimicrobial Properties of Euphorbia Tirucalli L.

Bioactive compounds extracted from natural sources can benefit human health. The aim of this work was to determine total phenolic content and antioxidant activity in extracts of Euphorbia tirucalli L. followed by identification and quantification of the phenolic compounds, as well as their antibacterial activities. Antioxidant activities were determined by DPPH and ABTS•+ assay. Identification of phenolic compounds was performed using high-performance liquid chromatography (HPLC), and antimicrobial activities were verified by agar dilution methods and MIC values. Total phenolic content ranged from 7.73 to 30.54 mg/100 g gallic acid equivalent. Extracts from dry plants showed higher antioxidant activities than those from fresh ones. The DPPH EC50 values were approximately 12.15 μg/mL and 16.59 μg/mL, respectively. Antioxidant activity measured by the ABTS method yielded values higher than 718.99 μM trolox/g for dry plants, while by the Rancimat® system yielded protection factors exceeding 1 for all extracts, comparable to synthetic BHT. Ferulic acid was the principal phenolic compound identified and quantified through HPLC-UV in all extracts. The extracts proved effective inhibitory potential for Staphylococcus epidermidis and Staphylococcus aureus. These results showed that extracts of Euphorbia tirucalli L. have excellent antioxidant capacity and moderate antimicrobial activity. These can be attributed to the high concentration of ferulic acid.

Atividade antioxidante da polpa, casca e sementes do noni (Morinda citrifolia Linn)

In an attempt to identify new sources of natural antioxidants and to clarify gaps in the scientific literature about the real beneficial properties attributed to Noni (Morinda citrifolia Linn), this study aimed to determine the chemical characterization and to evaluate antioxidant activity of the pulp, skin and seeds of Noni. Chemical composition (moisture, ash, protein, carbohydrates and lipids), bioactive compounds (total phenolics, total carotenoids and vitamin C), and the in vitro activity in aqueous, ethanolic and acetone extracts were determined. The results showed that compared to others fruits, the different parts of Noni have significant amounts of carbohydrates (27.21%, 9.70% and 8.37%) and protein (2.64%, 2.23 %, and 2.24 %) in seeds, skin and pulp, respectively. The pulp had a higher content of vitamin C (23.1 mg/100 g) and carotenoids (3.90 mg/100g).An amount of 109.81 mg/100 g of total phenolics was determined in the acetone extract of the pulp, followed by 76.01 and 28.75 mg/100g in the acetonic extracts of the skin and seeds, respectively and the ethanolic extract of the pulp with 20.33 mg/100g). All extracts showed antioxidant activity in vitro. The acetone and ethanolic extracts of the skin and seeds of Noni showed higher activity by the β-carotene / linoleic acid method while the ethanolic pulp extract had a higher antioxidant activity by DPPH and ABTS assay and the acetone extract of the pulp by the ABTS method. Data showed that Noni has high content of phenolic compounds with antioxidant capacity in vitro in different parts of the fruit.

Efeito do extrato aquoso de alecrim (Rosmarinus officinalis L.) sobre o estresse oxidativo em ratos diabéticos

OBJECTIVE: This study assessed the effect of aqueous rosemary extract on the oxidative stress of diabetic rats. METHODS: Aqueous rosemary extract was obtained by the sequential method. Total phenolic content was determined by the Folin Ciocateau method and antioxidant activity in vitro was determined by the following methods: β-carotene/linoleic acid, 2,2 Difenil-1-Picril-hidrazil and oxygen radical absorbance capacity. Male Wistar rats were distributed into 5 groups: control, diabetic, and three groups of diabetic animals treated with aqueous rosemary extract in different concentrations: 25, 50 or 100mg/kg orally for 30 days. Diabetes was induced by streptozotocin and, at the end of the experiment, blood was collected to assess the percentage of glycated hemoglobin; liver and brain tissues were collected for the determination of the antioxidant enzymes: superoxide dismutase, catalase, glutatione peroxidase and glutatione reductase. RESULTS: Aqueous rosemary extract contains high levels of phenolic compounds and significant total antioxidant activity in vitro according to the three methods. Aqueous rosemary extract at a concentration of 50mg/kg decreased the percentage of glycated hemoglobin and increased the activity of glutatiose peroxidase and catalase enzymes in the liver and superoxide dismutase in the brain of diabetic rats. However, no dose-response effect was observed in the other concentrations. CONCLUSION: Aqueous rosemary extract presented significant antioxidant capacity in vitro attributed to its high phenolic compound content. When administered to rats at a concentration of 50mg/kg, it proved to be efficient against the oxidative stress secondary to experimental diabetes.

NUMERICAL INVESTIGATION OF VORTEX-INDUCED VIBRATION OF A MARINE SCR

In this paper the dynamic response and fatigue analysis of a marine SCR (Steel Catenary Riser) due to vortex shedding is numerically investigated. The riser is divided in two-dimensional sections along the riser length. The discrete vortex method (DVM) is employed for the assessment of the hydrodynamic forces acting on these two-dimensional sections. The hydrodynamic sections are solved independently, and the coupling among the sections is taken into account by the solution of the structure in the time domain by the finite element method implemented in ANFLEX code [1]. Parallel processing is employed to improve the performance of the method. A master-slave approach via MPI (Message Passing Interface) is used to exploit the parallelism of the present code. The riser sections are equally divided among the nodes of the cluster. Each node solves the hydrodynamic sections assigned to it. The forces acting on the sections are then passed to the master processor, which is responsible for the calculation of the displacement of the whole structure. The time histories of stress are employed to evaluate the damage as well as the life expectancy of the structure by the rainflow method to count the cycles in the dynamic response.Copyright