Publications by authors named "Andrea C Montenegro"

Migration of nib Cd to the testa during fermentation can be achieved with high temperatures (> 45 °C) and low nib pH values (< 5.0) using spontaneous fermentation. However, this low pH can lead to low flavor quality.

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Lettuce is Colombia's most widely cultivated leafy vegetable, but in the absence of good agricultural practices, there is the risk of some pesticide residues that affect its safety and quality. This work aimed to identify the pesticides used by farmers for the lettuce crop, the iceberg variety ( var. capitata), in some municipalities of Cundinamarca (Colombia) and to investigate their residues by sampling and analysis.

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Several research efforts on cocoa have been focused on parameters for controlling the transformation process to guarantee homogeneity and quality of cocoa beans, the main raw material in the chocolate industry. The main changes that determine the final quality of cocoa-and also the product's homogeneity-occur during fermentation, given the great number of factors that affect the process. This research seeks to identify the most relevant factors affecting quality in order to offer higher-quality and more homogeneous cocoa for the chocolate industry.

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To investigate the in vitro anthelmintic efficacy of dividivi (Caesalpinia coriaria), a traditional medicinal plant used in Central America and the northern part of South America, extracts from the foliage of this plant were subjected to the egg hatching test (EHT) and larval exsheathment inhibition test (LEIT), against Haemonchus contortus. Four different extracts were evaluated: acetone-water (AW), methanol-water (MW), acetone-water-dichloromethane (AWD) and methanol-water-dichloromethane (MWD). The concentrations used for the EHT and LEIT tests ranged from 500 to 4000 µg mL-1 and six repetitions per concentration.

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Sandy soils in Florida are vulnerable to toxic metal pollution, and it is necessary to identify desirable amendments for the remediation of metal contaminated soils. Sorption and incubation experiments were conducted to compare the effectiveness of dolomite phosphate rock (DPR), humic acid activated dolomite phosphate rock (ADPR) and biochar (BC) in immobilizing Cd and Pb in two representative agricultural soils in south Florida (Alfisol-Riviera and Spodosol -Ankona series). The results showed that the soils had a low sorption capacity for metals with maximum sorption of 0.

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The reactivity of coordinated nitroxyl (HNO) has been explored with the [Fe(II)(CN)(5)HNO](3-) complex in aqueous medium, pH 6. We discuss essential biorelevant issues as the thermal and photochemical decompositions, the reactivity toward HNO dissociation, the electrochemical behavior, and the reactions with oxidizing and reducing agents. The spontaneous decomposition in the absence of light yielded a two-electron oxidized species, the nitroprusside anion, [Fe(II)(CN)(5)NO](2-), and a negligible quantity of N(2)O, with k(obs)≈5×10(-7)s(-1), at 25.

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Not so elusive: [Fe(II)(CN)(5)(HNO)](3-) has been characterized spectroscopically after the two-electron reduction of nitroprusside (see scheme). The complex is stable at pH 6, slowly decomposing to [Fe(CN)(6)](4-) and N(2)O. It is deprotonated at increasing pH value with oxidation of bound NO(-) to [Fe(II)(CN)(5)(NO)](3-).

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