Journal of Food Processing The latest articles from Hindawi Publishing Corporation © 2014 , Hindawi Publishing Corporation . All rights reserved. Effect of Processing Conditions on Calcium Content, Firmness, and Color of Papaya in Syrup Mon, 16 Jun 2014 08:18:45 +0000 Calcium impregnation is used as a pretreatment in the processing of papaya in syrup. The effect of process temperature (30 and 45°C), calcium source (calcium gluconate and calcium lactate), calcium concentration (0.5 and 1.5% w/w), and pH (4.2 and 6) were studied. The mineral source affected significantly the calcium uptake and the fruit firmness, and therefore, the product quality maximum content of calcium in the fruit was 240 and 72 mg/100 g fresh fruit in 8 h of treatment with calcium lactate and calcium gluconate, respectively. Greater firmness was observed in samples impregnated with calcium lactate. Impregnation treatments did not affect the surface color of fruit. Finally, the effect of cooking in sucrose syrup on product quality attributes (calcium retention, firmness, and color) was analyzed. Cooking in syrup had a positive effect on tissue firmness, despite the decrease of calcium content. During cooking in syrup, calcium content of treated fruit decreased between 9% and 37%. However, the calcium content of fruit in syrup was up to 6 times higher than in fresh fruit. Moreover, the cooking stage had a strong influence on color parameters, leading to a processed product darker than fresh fruit. Nancy Lovera, Laura Ramallo, and Viviana Salvadori Copyright © 2014 Nancy Lovera et al. All rights reserved. Effects of Different Enzymes and Concentrations in the Production of Clarified Lemon Juice Sun, 01 Jun 2014 08:49:41 +0000 Lemon juice obtained from Interdonato variety was treated with different enzymes at specific concentrations as depectinization processes to produce clear lemon juice and its concentrates. In addition, the best condition obtained from laboratory treatments was carried out in the local fruit juice plant. Effects of the processing steps on some quality parameters were investigated during the lemon juice production and the obtained concentrates were stored at −25°C for 180 days. The results showed that Novozym 33095 had the best depectinization effectiveness. Total pectin content of lemon juices decreased rapidly following the enzyme treatment and could not be detected following the filtration. Viscosity values decreased after pulp separation and the largest reduction was observed with the filtration. At the end of filtration in 40 μL/100 mL concentrations of each of the three enzymes, values of residual pectinmethylesterase (PME) activity were found to be in the lowest amounts. Filiz Uçan, Asiye Akyildiz, and Erdal Ağçam Copyright © 2014 Filiz Uçan et al. All rights reserved. Evaluation of Nitrite Radical Scavenging Properties of Selected Zimbabwean Plant Extracts and Their Phytoconstituents Sun, 06 Apr 2014 13:24:36 +0000 Oxidative stress resulting from accumulation of reactive oxygen species has been associated with disease. The search for natural antioxidants of plant origin is necessitated by the side effects associated with synthetic antioxidants currently available. The objective of the study was to determine the antioxidant activity of Combretum zeyheri, Combretum platypetalum, and Parinari curatellifolia extracts by determining nitrite radical scavenging ability. The nitrite radical scavenging assay was used to evaluate the antioxidant potential of the extracts. The total flavonoid content of P. curatellifolia methanol extract was determined by the aluminium calorimetric method. The aqueous and ethanolic leaf extracts of C. zeyheri, C. platypetalum, and P. curatellifolia extracts exhibited nitrite radical scavenging activity. The results show the scavenging activity in the order of potency: P. curatellifolia > C. platypetalum > C. zeyheri with concentration values of 103 µg/mL, 158 µg/mL, and 188 µg/mL for the ethanol extracts and 92.5 µg/mL, 97.5 µg/mL, and 198 µg/mL for the water extracts, respectively. P. curatellifolia ethanol extract was the most potent and the total flavonoid content was estimated to be 0.4 ± 0.05 mg/g quercetin and could account for the activity. Thus, our findings provide evidence that C. zeyheri, C. platypetalum, and P. curatellifolia leaf extracts could be potential sources of natural antioxidants. Fadzai Boora, Elaine Chirisa, and Stanley Mukanganyama Copyright © 2014 Fadzai Boora et al. All rights reserved. Moisture Diffusivity and Shrinkage of Fruit and Cladode of Opuntia ficus-indica during Infrared Drying Thu, 03 Apr 2014 13:40:00 +0000 Drying behaviour of prickly pear cladodes and fruits was studied with an Infrared dryer. The volume shrinkage for Opuntia ficus-indica products is calculated and a linear relation was established to describe the experimental variation of shrinkage of the product versus its moisture content. Effective diffusion coefficient of moisture transfer was determined using the Fick law at three drying temperatures (40, 50, and 60°C). Shrinkage was also included into the diffusion model for the determination of the effective diffusion coefficient. The obtained results of the effective moisture diffusivity, for the cladode and the fruit, were evaluated in the range of 1.77 × 10−10–5.07 × 10−10 m2/s and 2.53 × 10−10–7.6 × 10−10 m2/s, respectively. The values of the activation energies for cladode and fruit were estimated to be 45.39 and 47.79 kJ/mol, respectively. However, these values of moisture diffusivity were estimated independently of the evolution of moisture content during drying process. Therefore, a correlation (full quadratic equation) for moisture diffusivity as a function of moisture content and temperature was developed. The parameters are obtained by a multilinear regression method. This equation was found satisfactory to describe the diffusivity evolution function of moisture content and temperature with correlation coefficients of 91.5 and 95%. Amira Touil, Saber Chemkhi, and Fethi Zagrouba Copyright © 2014 Amira Touil et al. All rights reserved. Effects of the Domestic Cooking on Elemental Chemical Composition of Beans Species (Phaseolus vulgaris L.) Sun, 02 Mar 2014 07:34:34 +0000 Cooking is imperative for beans owing to the presence of compounds that can negatively affect nutritional value. Additionally, the heating of beans can increase protein digestibility and induce desirable sensory properties. However, cooking also causes considerable changes in the composition of numerous chemical constituents, including amino acids, vitamins, and minerals. For this, effects of domestic cooking on the essential element concentrations in various beans species (Phaseolus vulgaris L.) were investigated using jalo, fradinho, rajado, rosinha, bolinha, black, and common species. Elemental determination was made with flame atomic absorption spectrometry and inductively coupled plasma optical emission spectrometry after sample digestion in a closed-vessel microwave oven using a diluted oxidant mixture. Analytical methods were evaluated with an addition and recovery test and analysis of certified reference materials (apple and citrus leaves). Ca, Cu, K, and Mg were present mainly in rajado, Cu in jalo, Fe in black, S and Zn in fradinho, and P in rosinha species. Thermal treatment did not affect Cu, Fe, S, and Zn concentrations, but it increased Ca, K, Mg, P, and Zn concentrations in jalo and black species. Ca concentration decreased in fradinho and rajado species, as did Fe concentration in jalo and rajado species. Alessandra S. T. Ferreira, Juliana Naozuka, Gislayne A. R. Kelmer, and Pedro V. Oliveira Copyright © 2014 Alessandra S. T. Ferreira et al. All rights reserved.