Celeste Maria Patto de Abreu

Antinutrients in the cassava (Manihot esculenta Crantz) leaf powder at three ages of the plant

In Brazil, the cassava leaf meal (CLM) has been used to strive against undernourishment because it is a high source of vitamins and minerals. However, the wide variation in the chemical composition of the different cultivars, as well as their antinutritional substances may be a restriction to their uses. The levels of some antinutrients in CLM from five cultivars at three ages of the plant (TAP) were investigated, in order to select the cultivars and plant ages that would be more appropriate for human consumption. The lowest contents of antinutrients were observed in the 12-month old plants, except for nitrate and hemagglutinin from which the lowest contents were found for the 17 month old ones. The cultivar IAC 289-70 had the lowest antinutrient levels, except for saponin and oxalate. Thus, the cultivar IAC 289-70 at 12 months is the most appropriate for human consumption.

Efeito da estocagem e das condições de colheita sobre algumas propriedades físicas, químicas e nutricionais de três cultivares de feijão (Phaseolus vulgaris, L.)

In Brazil, bean stands out as one of the most important food and it is found nationwide. Providing essential nutrients, it is utilized an as alternative, in substituting of meats or other proteic products, but it presents some problems like low digestibility if compared to animal proteins, which can be reduced under special storage conditions. This research aimed to evaluate the effect of storage and harvest conditions on some nutritious, physical and chemical properties of three bean cultivars. The results show that the average moisture contents were higher before storage and, after storage, the grains came into hygroscopic equilibrium with the environment in the studied cultivars. Early harvested cultivars presented higher water-absorbing capacity, which reduced during the storage period at the harvested samples. The level of phenolic compounds was higher in early harvested samples, which makes us conclude that these compounds would not be affecting the grain hydration capacity. The early harvested samples presented higher values of protein. After storage period, beans presented protein content slightly higher. The digestibility reduced during the months of storage. Reaction between proteins and phenols in processing may be associated to the low digestibility due to the negative correlation between the in vitro digestibility and tannin content present in the product.

Effect of processing and roasting on the antioxidant activity of coffee brews

The aim of this work was to evaluate the effect of processing and roasting on the antioxidant activity of coffee brews. Brews prepared with light, medium and dark roasted coffees were analyzed. The pH, total solids content, polyphenols content, reducing substances and chlorogenic acids content were determined. The antioxidant activity of aqueous extracts, the guaicol decolorizing and the capacity to inhibit lipid peroxidation were also analyzed. The antioxidant activity of coffee brews were concentration-dependent. A progressive antioxidant activity and polyphenols content was observed decreasing with roasting. The light roasted coffee showed the highest antioxidant activity and dark roasted coffee showed the lowest antioxidant activity. The results indicate that the ingestion of coffee brews prepared with light and medium roasted coffees might protect cells from oxidative stress damages.

Avaliação da atividade fungitóxica de óleos essenciais de folhas de Eucalyptus sobre Fusarium oxysporum, Botrytis cinerea e Bipolaris sorokiniana

A maioria das plantas sao resistentes aos diferentes patogenos, e essa resistencia pode estar relacionada a existencia de compostos fungistaticos naturalmente produzidos. Com o presente trabalho, avaliou-se a atividade fungitoxica de oleos essenciais de eucaliptos. Os oleos foram obtidos de folhas dos eucaliptos mediante arraste a vapor de agua, utilizando o aparelho de Clevenger modificado. Nos ensaios biologicos, foram empregados os fitopatogenos Fusarium oxysporum, Botrytis cinerea e Bipolaris sorokiniana. O crescimento dos microorganismos na presenca de diferentes concentracoes de oleo (5, 50 e 500 mg/Kg), usando os meios de cultura BDA (Batata-Dextrose-Agar) e PCA (Batata-Cenoura-Agar), foi avaliado. Nas concentracoes de 500 mg/Kg dos oleos, foram observadas inibicoes significativas no crescimento micelial das especies fungicas, apos periodo de 7 dias. No entanto, o oleo essencial de Eucalyptus urophylla foi o que apresentou maior acao fungitoxica, que foi atribuida a presenca do composto denominado globulol, ausente no E.camaldulensis e no E. citriodora.

Remoção de polifenóis da farinha de folhas de mandioca

Even featuring a relatively high level in proteins, the flour of cassavaleaves presents low digestibility, mainly, due to the presence of such substances as polyphenols. Seeking to improve the protein availability of such flour, three solvents (water, ethanol 50mL/100mL and ammonium hydroxide 1mol/L) were used for the removal of the polyphenols. Mature leaves of cassava were picked in phase of vegetative development, in three repetitions, they were placed in paper trays and dried under shadow, on a wood bench, in a shut and airy place, at room temperature. After drying, the petioles were removed and the leaves were ground and sieved using 40-mesh sieve. The flour was submitted, before e after removal of polyphenols, to the analyses of moisture, neutral detergent fiber (NDF), acid detergent fiber (ADF), total sugars, crude protein, vitamin total C, b-carotene, cyanide, trypsin inhibitor, polyphenols and in vitro protein digestibility. After the removal of the polyphenols, there was a decrease in the levels of total sugars, vitamin total C, trypsin inhibitor and polyphenols and an increase in the levels of NDF, ADF, crude protein, b-carotene and in vitro protein digestibility. Of the solvents employed in the removal the polyphenols, the ammonium hydroxide was the most effective, with index of removal of 94%, followed by the ethanol (83%) and water (65%). The in vitro protein digestibility increased of 74%, when the solvent employed in the removal of the polyphenols was the ammonium hydroxide.

Textura de goiabas "Pedro Sato" submetidas à aplicação de cloreto de cálcio

Among the techniques used to maintain the post-harvest quality of fruits, stands out the application of calcium, usually associated to the refrigeration. However, not all the producers have access to cold cameras, therefore it was aimed at in this work, to evaluate the isolated treatment with calcium chloride in the maintenance of the appearance of guavas (Psidium guajava L.) destined to the consumption “in nature”, stored in environmental conditions. The hydrothermical treatment at the temperature of 30oC, with calcium chloride 1g/100 mL, was tested comparing with fruits without treatment. Soon after the fruits were stored under environmental conditions (22,6oC (±1), UR 75% (±5) for four days. After the storage, the contents of total and soluble pectin and the pectinametilesterase and poligalacturonase activities were evaluated. The employment of calcium affected the analyzed characteristics providing smaller content of soluble pectin and lower activities of pectinametilesterase and poligalacturonase, promoting a less intense softening, maintaining the firmness of the fruits during the storage period.

INFLUÊNCIA DO PROCESSAMENTO E DA TORREFAÇÃO SOBRE A ATIVIDADE ANTIOXIDANTE DO CAFÉ (Coffea arabica)

The aim of this work is to evaluate the influence of processing (semi-dry and dry) and roasting (light, medium and dark) on the antioxidant activity of coffee brews, using tests to determine the reducing power and the DPPH scavenging, Fe+2 chelating and lipid peroxidation inhibition activities. All of the coffee brews presented concentration-dependent antioxidant activity. The light coffee samples presented the higher reducing power and DPPH scavenging activity. Its ion chelating capacity was similar to the medium samples, but was less than the green coffee chelating capacity. The semi-dry processing was more efficient than the dry processing only for the reducing power. All of the samples presented high lipid peroxidation inhibition activity. Based on the results the degree of coffee roasting seems to be more important than the processing to determine the antioxidant activity of brews.

Alterações pós-colheita da "fruta-de-lobo" (Solanum lycocarpum St. Hil.) durante o amadurecimento: análises físico-químicas, químicas e enzimáticas

Estudaram-se, neste trabalho, algumas modificacoes fisico-quimicas, quimicas e enzimaticas, em pos-colheita, durante o amadurecimento da fruta-de-lobo, comparando-as com as de outros frutos. Os frutos colhidos de plantas nativas no inicio do estadio de amadurecimento foram selecionados e armazenados durante 18 dias a temperatura ambiente (17,1 a 26,9oC). Os frutos foram lavados com agua destilada, descascados, picados, congelados em nitrogenio liquido e liofilizados ate massa constante. O delineamento experimental utilizado foi o inteiramente casualizado, com quatro repeticoes de 3 frutos. Os valores de pH e acidez titulavel nao variaram estatisticamente durante o amadurecimento. A atividade de amilase e os teores de amido diminuiram gradativamente com o aumento dos acucares soluveis totais e nao redutores, enquanto os teores dos redutores se mantiveram constantes. Os teores de pectinas totais e soluveis diminuiram, enquanto a atividade de pectinametilesterase manteve-se constante. As atividades das enzimas poligalacturonase e polimetilgalacturonase nao foram detectadas no fruto. Observou-se diminuicao dos teores de polifenois e das atividades das enzimas peroxidase e polifenoloxidase e consequente diminuicao do escurecimento da polpa do fruto.

Estudo dos efeitos do silício e do fósforo na redução da disponibilidade de metais pesados em área de mineração

This study was developed with a soil contaminated by heavy metals, with the purpose of evaluating the action of silicon and phosphorus as protection agents through simple extractions by DTPA. The collected samples were prepared and incubated with five doses of silicon and five doses of phosphorus, with four replicates, amounting to 100 experimental units. After 30 and 60 days, samples of each treatment were collected, submitted to pH analyses and simple extraction by DTPA. The amounts of DTPA-extracted metals depended on the doses of silicon and phosphorus and on the pH. Treatments with silicon and phosphorus was efficient in decreasing the availability of heavy metals in soil.

Produção de matéria seca e de grãos por plantas de feijoeiro (Phaseolus vulgaris L.) cultivadas em solos tratados com metais pesados

This work aimed at evaluating the contents of extractable Cd, Pb, Zn and Cu with a solution of DTPA (diethyleneaminopentacetic acid) and to relate them with the production of dry material and grain production of bean plants under two conditions of experimentally contaminated soil materials with Cd, Pb, Cu and Zn: (i) samples of distrofic red latosol and (ii) humic yellow-red latosol. A decrease in the yield of dry matter was observed for all treatments, if compared with the zero-dose control sample; the grain yield was affected for the soil samples treated with Cd and Cu but only slightly for those treated with Pb and Zn.