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Neves Junior A.C.V.,Federal Rural University of Rio de Janeiro | Melo A.,University of Porto | Pinho C.,University of Porto | Coneglian R.C.C.,Federal Rural University of Rio de Janeiro | And 2 more authors.
Journal of Chemometrics | Year: 2014

Cyanamide is widely used for agricultural purposes; therefore, its residues can be found in water. A new method was developed for its quantification using in situ derivatization with 2,6-dimethyl-4-quinolinecarboxylic acid N-hydroxysuccinimide ester followed by dispersive liquid-liquid microextraction (DLLME) and high-performance liquid chromatography/fluorescence analysis. Multivariate chemometric techniques were successfully used to obtain the optimum conditions for direct derivatization and DLLME extraction. Derivatization parameters and DLLME extraction conditions were optimized by a two-step design, 2k factorial design for screening, and central composite design for optimization. Best derivatization conditions were addition of 600 μL of derivatizing reagent, a temperature of 4°C, and pH 8.5, whereas for optimum extraction 800 μL of solvent, 30% NaCl conc. w/v, and pH 3.8 were chosen. The analytical performance of the method for routine analysis was evaluated. Excellent linearity was achieved from 10 to 200 μgL-1 with a correlation factor of 0.9996. Precision ranged from 3.5% to 5.5% for intraday assays and 8.5% to 8.6% for interday assays. The mean recoveries performed on water from different origins (ground, river, sea, tap, and mineral) at three levels of concentration (20, 75, and 200 μgL-1) ranged from 90.2% to 110.2%. © 2014 John Wiley & Sons, Ltd. Source


Neves Jr. A.C.V.,Federal Rural University of Rio de Janeiro | Coneglian R.C.C.,Federal Rural University of Rio de Janeiro | Soares A.G.,Postharvest Physiology and Technology of Fruits and Vegetables | Freitas D.G.C.,Postharvest Physiology and Technology of Fruits and Vegetables | And 3 more authors.
Acta Horticulturae | Year: 2012

Edible coatings can be an important tool to ensure quality and increase the shelf life of minimally processed (MP) persimmon. Four different types coatings were evaluated: 1) cassava starch (CS, 3.5% with 0.0135% potassium permanganate, 0.0135% calcium lactate, 1% glycerol and 5% polyethylene glycol 400); 2) sodium alginate (SA, 1% with 1500 mg g-1 potassium sorbate, 30 ml L-1 calcium chloride solution 0.4%, 0.5% glycerol and 5% polyethylene glycol 400); 3) carboxymethyl cellulose (CMC, 1% with 0.25% citric acid and 5% of polyethylene glycol 400); and 4) bovine gelatin (5% with 1500 mg g-1 potassium sorbate and 15% glycerol). Thickness, permeability to water vapor, oxygen and carbon dioxide, and the elasticity modulus of the coatings were determined. Preliminary sensory analyses of minimally processed fruit treated with edible coatings were performed. It was found that the CS coating had higher strength and the SA coating the higher elasticity. The CMC coating showed the highest CO2/O2 ratio and the lowest permeability to water vapor. The CS coating showed the lowest CO2/O2 permeability ratio and the highest water permeability. The sensory analysis indicated that the coatings CS and CMC were more preferred for use on minimally processed persimmon. Source


Neves Jr. A.C.V.,Federal Rural University of Rio de Janeiro | Coneglian R.C.C.,Federal Rural University of Rio de Janeiro | Soares A.G.,Postharvest Physiology and Technology of Fruits and Vegetables | Fonseca M.J.O.,Postharvest Physiology and Technology of Fruits and Vegetables | Alencar C.A.,Postharvest Physiology and Technology of Fruits and Vegetables
Acta Horticulturae | Year: 2012

The 'Mikado' persimmon is a very astringent fruit. This fruit requires an adequate process to reduce its astringency and produce quality acceptable for minimally processing (MP). The objective was to evaluate the exposure time of persimmon to alcohol vapor (AV) 70% (7.00 ml alcohol kg-1 fruit) to reduce the astringency of the fruit before fresh cut processing. The experiment was conducted with fruits from the city of Sumidouro, Rio de Janeiro. The fruits were transported to Embrapa Food Technology during the night to avoid high temperatures. The fruits were collected during seven days. At each harvest, fruits were selected, cleaned and subjected to AV at different exposure times. The treatments were: T1-10 h; T2-36 h; T3-55 h; T4-83 h; T5-107 h; T6-130 h; and T7-155 h. The fruit quality was evaluated through the following analyses: firmness, pH, total titratable acidity (TTA), total soluble solids (TSS), and total tannin contents. Sensory analysis (SA) was also conducted to determine the detection threshold of astringency correlated with the concentration of soluble tannin in the pulp. There was a decrease of firmness and soluble tannin concentration of the pulp with increased duration of exposure to alcohol vapor. There were variations in the TTA and the TSS contents over time. It was observed, through sensory analysis, that astringency was felt, by the panelists, up to 0.8161 μg 100 g-1 of soluble tannin in the pulp. Regarding the firmness of the fruit, the more appropriate exposure time, to AV, was 55 hours. According to sensory analysis, the best time of exposure was 83 hours. However, with 83 hours of exposure to AV the fruits firmness declined below acceptable levels for a product to be minimally processed. Source

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