Paulo César Stringheta

Seasonal Variation, Chemical Composition and Antioxidant Activity of Brazilian Propolis Samples

Total phenolic contents, antioxidant activity and chemical composition of propolis samples from three localities of Minas Gerais state (southeast Brazil) were determined. Total phenolic contents were determined by the Folin–Ciocalteau method, antioxidant activity was evaluated by DPPH, using BHT as reference, and chemical composition was analyzed by GC/MS. Propolis from Itapecerica and Paula Cândido municipalities were found to have high phenolic contents and pronounced antioxidant activity. From these extracts, 40 substances were identified, among them were simple phenylpropanoids, prenylated phenylpropanoids, sesqui- and diterpenoids. Quantitatively, the main constituent of both samples was allyl-3-prenylcinnamic acid. A sample from Virginópolis municipality had no detectable phenolic substances and contained mainly triterpenoids, the main constituents being α- and β-amyrins. Methanolic extracts from Itapecerica and Paula Cândido exhibited pronounced scavenging activity towards DPPH, indistinguishable from BHT activity. However, extracts from Virginópolis sample exhibited no antioxidant activity. Total phenolic substances, GC/MS analyses and antioxidant activity of samples from Itapecerica collected monthly over a period of 1 year revealed considerable variation. No correlation was observed between antioxidant activity and either total phenolic contents or contents of artepillin C and other phenolic substances, as assayed by CG/MS analysis.

Black bean (Phaseolus vulgaris L.) as a protective agent against DNA damage in mice

This study was designed to evaluate the toxicogenetic or protective effect of cooked and dehydrated black beans (Phaseolus vulgaris L.) in bone marrow and peripheral blood cells of exposed mice. The frequency of micronuclei detected using the bone marrow erythrocyte micronucleus test and level of DNA lesions detected by the comet assay were chosen as end-points reflecting mutagenic and genotoxic damage, respectively. Initially, Swiss male mice were fed with a 20% black bean diet in order to detect mutagenic and genotoxic activity. However, no increase in the frequency of bone marrow micronucleated polychromatic erythrocytes (MN PCEs) or DNA lesion in leukocytes was observed. In contrast, received diets containing 1, 10 or 20% of black beans, a clear, but not dose-dependent reduction in the frequency of MN PCEs were observed in animals simultaneously treated with cyclophosphamide, an indirect acting mutagen. Similar results were observed in leukocytes by the comet assay. Commercial anthocyanin was also tested in an attempt to identify the bean components responsible for this protective effect. However, instead of being protective, the flavonoid, at the highest dose administered (50 mg/kg bw), induced primary DNA lesion, as detected by the comet assay. These data indicate the importance of food components in preventing genetic damage induced by chemical mutagens, and also reinforce the role of toxicogenetic techniques in protecting human health.

Anticarcinogenic effects of polyphenolics from mango (Mangifera indica) varieties.

Many polyphenolics contained in mango have shown anticancer activity. The objective of this study was to compare the anticancer properties of polyphenolic extracts from several mango varieties (Francis, Kent, Ataulfo, Tommy Atkins, and Haden) in cancer cell lines, including Molt-4 leukemia, A-549 lung, MDA-MB-231 breast, LnCap prostate, and SW-480 colon cancer cells and the noncancer colon cell line CCD-18Co. Cell lines were incubated with Ataulfo and Haden extracts, selected on the basis of their superior antioxidant capacity compared to the other varieties, where SW-480 and MOLT-4 were statistically equally most sensitive to both cultivars followed by MDA-MB-231, A-549, and LnCap in order of decreasing efficacy as determined by cell counting. The efficacy of extracts from all mango varieties in the inhibition of cell growth was tested in SW-480 colon carcinoma cells, where Ataulfo and Haden demonstrated superior efficacy, followed by Kent, Francis, and Tommy Atkins. At 5 mg of GAE/L, Ataulfo inhibited the growth of colon SW-480 cancer cells by approximately 72% while the growth of noncancer colonic myofibroblast CCD-18Co cells was not inhibited. The growth inhibition exerted by Ataulfo and Haden polyphenolics in SW-480 was associated with an increased mRNA expression of pro-apoptotic biomarkers and cell cycle regulators, cell cycle arrest, and a decrease in the generation of reactive oxygen species. Overall, polyphenolics from several mango varieties exerted anticancer effects, where compounds from Haden and Ataulfo mango varieties possessed superior chemopreventive activity.

Optimization of methodology to analyze ascorbic and dehydroascorbic acid in vegetables

In this study, different solutions to extract vitamin C were tested. High-performance liquid chromatography was chosen and the conditions were based on isocratic elution in reverse phase column. Dehydroascorbic acid was determined indirectly after its reduction using dithiothreitol. The use of metaphosphoric acid to stabilize the vitamin C was shown to be required and it was necessary to neutralize the pH of the extract to apply dithiothreitol. The average recovery was 90% in collard and tomato samples. The presence of oil did not interfere in extraction and the methodology can be used to analyze stir fried vegetables.

Políticas de saúde e alegações de propriedades funcionais e de saúde para alimentos no Brasil

O trabalho estabelece a relacao entre as diretrizes das politicas publicas de saude brasileiras e os criterios adotados pela Anvisa para aprovacao das alegacoes de propriedades funcionais e, ou, de saude para alimentos e para substâncias bioativas e probioticos isolados. Comenta a legislacao brasileira sobre alimentos com alegacoes de propriedades funcionais e, ou, de saude, novos alimentos e substâncias bioativas e probioticos isolados, evidenciando a obrigatoriedade de registro destes produtos junto aos orgaos competentes. Apresenta as diretrizes da Politica Nacional de Alimentacao e Nutricao, Politica Nacional de Promocao da Saude, Guia Alimentar para a Populacao Brasileira e Estrategia Global sobre Dieta, Atividade Fisica e Saude da Organizacao Mundial de Saude. Ressalta a convergencia das diretrizes destas politicas que objetivam a reducao das doencas cronicas nao-transmissiveis na populacao atraves da promocao da alimentacao saudavel e da atividade fisica. Destaca as orientacoes direcionadas aos governos e a industria para a implementacao dessas medidas. Apresenta criterios de avaliacao da base cientifica das alegacoes propostos por orgaos internacionais. Objetiva oferecer subsidios para o entendimento da influencia da tecnologia de alimentos sobre a saude publica e para o entendimento dos criterios adotados pela Anvisa, na avaliacao das alegacoes de propriedades funcionais e de saude.

Qualidade da manga e polpa da manga Ubá

Uba mango (Mangifera indicates L. var. Uba) has excellent flavor qualities and a tasty, yellow and succulent pulp. It contains a high content of soluble solids, around 14 °Brix, acidity of 0.2% as citric acid and ratio 70, besides being rich in potassium and vitamins A and C. The fruit has soft and short fibers, and can be consumed fresh or be industrialized, especially for the production of pulp and juice. This variety possesses an excellent industrialization yield, by greatly reducing processing, with a consequent reduction in the final production costs. Uba mango supplied to a pulp and juice agroindustry in the Zona da Mata Mineira area had its quality determined through fruit and pulp analyses. During the 2003/2004 harvest period, the Dirty Mangos (DM), as were denominated the fruits that arrived at the industry, presented an average initial count of 7.34 log CFU mesophyllic aerobics/mango. After cleaning, the fruits were called Clean Mangos (CM), and had an average of 5.62 log CFU/mango, presenting an average reduction of 1.72 log cycles. In the 2004/2005 harvest period, the DM presented an average initial count of 7.02 log CFU mesophyllic aerobics/mango and the CM, an average of 5.76 log CFU/mango, with an average reduction of 1.52 log cycles. The mango pulp presented values for pH, total soluble solids, total acidity, total soluble solids/total acidity ratio, total solids and total soluble sugars, in accordance with the legislation requirements. The color coordinates presented values indicating that the pulp has a yellow-orange characteristic color.

Color evaluation of carbon monoxide treated porcine blood

The stability of liquid porcine blood, treated with carbon monoxide (CO) at different pH values (7.40, 6.70, and 6.00) up to its complete saturation, was studied. Lowering the pH from 7.40 to 6.70 resulted in a decrease in the amount of CO necessary to obtain 100% carboxyhemoglobin. Further pH lowering to 6.00 did not result in additional reduction in the amount of gas. During 4 days of refrigerated storage CO treated liquid blood maintained, at every pH, a more stable and attractive red color than fresh blood, which was a result of an increase (P<0.05) of a(*) (redness) and b(*) (yellowness) values and no variation (P>0.05) on L(*) (lightness) value. Hue (h(*)) and chroma (C(*)) decreased in the untreated blood but not in the CO-treated blood. The results indicate that blood saturation with CO yields a product having greater potential for use in meat products without compromising its visual appearance.

Avaliação de genótipos de tomateiro cultivados em ambiente protegido e em campo nas condições edafoclimáticas de Viçosa

The influence of the temperature, air humidity, brightness and their effects on tomato yield growth in protected environment and in the field were evaluated. Two experiments were carried out in different atmospheres from January to May 2002. The cultivar Santa Clara, hybrid Carmen and an accession BGH-320 from the Germplasm Vegetable Bank of Universidade Federal de Vicosa, Minas Gerais State, Brazil, were used in both experiments. The experiment under protected environment was carried out in a greenhouse type chapel and the other in the field, under natural conditions. In general higher production of fruits was observed on plants cultivated under protected environment than in open field. The Carmen hybrid exceeded the other genotypes in yield in the protected environment. Accession BGH-320 presented lower total yield under protected environment than the other two genotypes. In the field the accession BGH-320 presented higher total yield than Santa Clara cultivar and a similar yield than Carmen. In the field, the commercial yield did not differ among the three genotypes.

Produção e sabor dos frutos de tomateiro submetidos a poda apical e de cachos florais

The effect of top-shoot and floral cluster pruning on the production and flavor of the tomato fruits were experimentally evaluated (May to November of 2002). The experimental design was of randomized blocks, with five treatments, seven replications, and eight-plant plots. Seedlings from cultivar Kindyo of indeterminate growth habit, were used. Treatments were: (A) pruning of the 1st floral cluster and top-shoot pruning above the 7th floral cluster; (B) same as A, but without top-shoot pruning and with pruning of the floral clusters above the 7th cluster; (C) without pruning the 1st floral cluster, but with top-shoot pruning above the 6th floral cluster; (D) same as C, but without top-shoot pruning and with pruning of floral clusters above the 6th.; (E) without top-shoot and floral cluster pruning, but evaluating only the first six floral clusters. Tomato fruits were harvested, graded and weighed in a week basis, after reaching maturity (100% red). Data were submitted to variance analysis and Tukeys test (p<0.05). Pruning of the 1st floral cluster was detrimental for commercial production of tomato fruits. The preservation of plant growth in combination with pruning of floral cluster above the sixth, without pruning the first floral cluster (treatment D), significantly increased the production of large fruits (101.5 t ha-1) in relation to the other treatments (treatment A: 74.9; B: 71.4; C: 80.3; E: 78.9 t ha-1). However, for commercial production, treatment D (127.7 t ha-1) significantly differed only from treatments A and B (106.6 and 99.4 t ha-1, respectively). For total production, flavor, oBrix, and pH, whose averages were respectively 149.4 t ha-1; 13; 4,32%, and 4,34, there were no significant differences.

Pró-vitaminas A em hortaliças comercializadas no mercado formal e informal de Viçosa (MG), em três estações do ano

With the aim of providing data on the influence of climate and form of commercialization on carotenoid of vegetables, this study evaluate the content of a and b carotene and vitamin A value of seven vegetables (sweet potato, carrot, squash, green pepper, okra, tomato and green bean) market in Vicosa (MG), Brazil, using High Performance Liquid Chromatography (HPLC). It was compared vegetables commercialized in two local markets and in the free market during spring, summer and autumn. Carrot presented the highest values of a and b-carotene (31.17 e 58.18 µg/g, respectively), followed by squash (4.33 and 23.16 µg/g, respectively), while sweet potato presented the lowest value of b carotene (0.51 µg/g). The vitamin A values varied as the profile of a and b-carotene content. The results showed that, except for carrot and okra, there was no significant influence of the market type on the content of carotenoids. The variation of the content of a and b-carotene in the seasons was not important, and only green pepper presented significantly different values. Portions of 100 g of analyzed vegetables supply 3 to 78% of vitamin A recommendation.