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Registros recuperados: 7
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A novel procedure to measure the antioxidant capacity of Yerba maté extracts Ciênc. Tecnol. Aliment.
Hartwig,Vanessa Graciela; Brumovsky,Luis Alberto; Fretes,Raquel María; Boado,Lucila Sánchez.
Yerba maté extracts have in vitro antioxidant capacity attributed to the presence of polyphenolic compounds, mainly chlorogenic acids and dicaffeoylquinic acid derivatives. DPPH is one of the most used assays to measure the antioxidant capacity of pure compounds and plant extracts. It is difficult to compare the results between studies because this assay is applied in too many different conditions by the different research groups. Thus, in order to assess the antioxidant capacity of yerba maté extracts, the following procedure is proposed: 100 µL of an aqueous dilution of the extracts is mixed in duplicate with 3.0 mL of a DPPH 'work solution in absolute methanol (100 µM.L-1), with an incubation time of 120 minutes in darkness at 37 ± 1 °C, and then...
Tipo: Info:eu-repo/semantics/article Palavras-chave: DPPH; Yerba maté; Antioxidant capacity; Ilex paraguariensis.
Ano: 2012 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0101-20612012000100019
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Assessment of oxidation of leaves of Ilex paraguariensis (St. Hil) BABT
Molin,Rochele Fernanda; Valduga,Alice Teresa; Di Luccio,Marco; Dartora,Nessana; Cichoski,Alexandre José; Pistore,Mônica; Rigo,Elisandra.
This work aimed to study the oxidation of leaves of Ilex paraguariensis St. Hil, in a process similar to the oxidation of Camellia sinensis, with the purpose of developing new products based on yerba maté. So far, no previous systematic study about the oxidation of yerba maté has been found elsewhere. A Plackett-Burman experimental design was used for the screening of the significant parameters that affected the oxidation. The oxidation was indirectly quantified by following the changes in the product color, water activity, and pH with the time of processing. The factors that most influenced the process were the age of the leaves and the relative humidity of the oxidation chamber. The differences between the treatments were more evident after 3, 6 12 and...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Physicochemical parameters; Yerba maté; Leave; Extract; Experimental design.
Ano: 2011 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132011000200016
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Chlorophyll stability in yerba maté leaves in controlled atmospheres BABT
Morawicki,Rubén O.; Schmalko,Miguel E.; Känzig,Rodolfo G..
The objective of this research was to investigate the stability of chlorophyll in yerba maté leaves in controlled atmospheres of CO2/air mixtures and different water activities at 25°C.Two levels of water activity were selected corresponding to saturated salt solutions of LiCl (a w=0.113) and MgCl2(a w=0.330) and three levels of CO2/air mixtures (0/100,20/80 and 40/60). The chlorophyll content was evaluated using a liquid chromatography HPLC technique. Experimental values varied between 2.16 and 0.61 mg/g of dry matter. For each sample, 5 determination were made during 58 days. Experimental values were fitted to an equation describing a first order reaction. In all cases, the agreement was good with P<3 10-3. The initial concentration of chlorophyll...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Yerba maté; Chlorophyll stability; Controlled atmosphere.
Ano: 1999 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89131999000100012
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Dimethoate degradation in plants and during processing of yerba maté leaves BABT
Schmalko,Miguel E.; Ramallo,Laura A.; Ferreira,Darío; Berlingheri,Rubén D..
The objective of this research was to study degradation kinetics of dimethoate in plants of Ilex paraguariensis Saint Hilaire (or yerba maté) and during its processing. To determine dimethoate concentration, a capillary gas chromatography technique with a mass selective detector was used. Half-life times in plants ranked between 9.8 and 11.8 days. During processing, with a blanching and two drying steps, dimethoate concentration decayed to a 22.7% of its initial value (in dry basis); while during seasoning step (at 45°C), half-life time was 17.3 days. With these values, preharvest safety interval was determined.
Tipo: Info:eu-repo/semantics/article Palavras-chave: Dimethoate; Pesticide; Degradation; Processing; Ilex paraguariensis; Yerba maté.
Ano: 2002 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132002000600003
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Extraction optimization of soluble compounds of yerba maté BABT
Sambiassi,César; Escalada,Andrea M.; Schmalko,Miguel E..
The objective of this research was the extraction optimization of water soluble compounds of yerba maté. Measures variables were extract concentration and weight of leaves and twigs. Controlled variables were time and temperature of extraction and water/solid relation. A surface response method of three variables was used as experimental design, with 20 experiences in each case. The range of each variable, defined in the experimental design, was: extraction time, 13.2 to 46.8 minutes; temperature, 48.2 to 81.8°C and water solid relation, 4.64 to 11.36 g water/100 g of dry solid. Extract weight varied from 13.14 to 29.56 g in leaves and 8.98 to 16.32 g in twigs (each one per 100 g of dry solid). Extract concentration varied between 2.17 and 3.43 g/100 ml in...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Yerba maté; Soluble compounds; Optimization.
Ano: 2002 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132002000200010
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Natural antioxidant from yerba maté (Ilex paraguariensis St. Hil.) prevents hamburger peroxidation BABT
Ferreira,Erica Lemos; Sampaio,Geni Rodrigues; Torres,Elizabeth Aparecida Ferraz da Silva; Bastos,Deborah Helena Markowicz.
The aim of this study was to evaluate whether yerba maté alcoholic extracts at very low concentrations (0.01 and 0.1%), prevent/retard lipid peroxidation in beef hamburgers without impairing sensory acceptability. For this TBARs and hexanal levels, fatty acid profile and cholesterol oxides were evaluated as oxidation parameters in beef hamburgers during 90 days' storage. The addition of 0.01% yerba maté ethanolic extracts proved inefficient in restraining the lipid peroxidation while the addition of 0.1% resulted in efficient antioxidant activity. Sensory evaluation of hamburger containing 0.1% yerba maté ethanolic extracts showed good acceptability. Yerba maté ethanolic extracts could entirely or partially replace the phenolic synthetic antioxidants in...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Yerba maté; Lipid oxidation; Natural antioxidants; Hamburger.
Ano: 2011 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132011000400021
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The Effect of Mg2+, Cu2+ and Zn2+ pre-treatment on the color of yerba maté (Ilex paraguariensis) leaves BABT
Scipioni,Griselda Patricia; Argüello,Beatriz del Valle; Schmalko,Miguel Eduardo.
The aim of this work was to study the effect of alkaline blanching followed by an immersion in salt solutions of Mg2+, Cu2+ and Zn2+ on color preservation of Yerba Maté leaves. The concentration of NaOH in the alkaline solution influenced all of the color parameters. Ion concentration and dipped time influenced only some color parameters. The color parameters of the product obtained with different treatments were different from the control sample (blanched with boiling water instead of alkaline blanching) and from the product obtained via industrial processing. The green color in the pre-treated and control samples was more intense (greater values of -a) and darker (low values of L and b). Ionic and ash content in the leaves increased with the treatments.
Tipo: Info:eu-repo/semantics/article Palavras-chave: Color; Yerba maté; Ionic treatment; Drying.
Ano: 2010 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132010000600027
Registros recuperados: 7
Primeira ... 1 ... Última
 

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