Kinetic evaluation of color, texture, polyphenols and antioxidant capacity of Irish York cabbage after blanching treatment

School of Food Science and Environmental Health, College of Sciences and Health, Dublin Institute of Technology, Cathal Brugha Street, Dublin 1, Ireland
Food Chemistry (Impact Factor: 3.26). 01/2011; 131(1). DOI: 10.1016/j.foodchem.2011.08.032

ABSTRACT In the present work, York cabbage was blanched between 80 to100°C with an increment of 5°C for up to 14 min and kinetics of the different physio-chemical properties were studied. Significant reductions in the texture, color, polyphenols (PPs) and antioxidant (AO) capacity were observed due to blanching. Total phenolic and flavonoid content retained ranged from 19.6-24.5 and 22.0-25.7%, respectively. Heavy losses in the AO capacity also occurred as a result of blanching, which was evident with a loss of 74.0-82.0% in activity as compared to raw York cabbage. Textural studies showed that blanching caused a significant reduction in firmness in the range of 24.0-73.2% and similar trend also observed for color. Kinetic evaluation of degradation was carried out for all the studied quality parameters. The fractional conversion (FC) first-order reaction model showed a good fit for the different studied parameters with the coefficient of determination ranging from 0.892-0.992 except for texture and color, which followed first order and zero order kinetics, respectively. The temperature effect followed the Arrhenius law with activation energy for polyphenolic content, AO capacity, color and texture calculated as 9.22-11.5, 9.05-35.05, 15.73 and 33.8 kJ/mol K, respectively.

  • [Show abstract] [Hide abstract]
    ABSTRACT: The aim of this work was to show that the leaching process of saponins from quinoa (Chenopodium quinoa Willd.) seeds during washing with water, as is generally practiced by people in South America, can be modeled using mathematical expressions related to Fick's second law. Experimental data were obtained through batch extraction with a ratio of quinoa to water of 1:10 under constant agitation for processing time between 15 and 120 min at 20, 30, 40, 50 and 60C. It was found that residual saponin concentration in the quinoa seeds decreased as washing temperature increased. Leaching rate followed the Arrhenius relationship, with calculated effective saponin diffusion coefficient between (5.05 ± 0.15) × 10−10 and (32.50 ± 1.65) × 10−10 m2/s as the temperature increased from 20 to 60C. Several mathematical models to describe the kinetic behavior of the leaching process were analyzed. The modified Henderson–Pabis model had the best fit quality as shown by statistical analysis. PRACTICAL APPLICATIONSDuring processing of quinoa for human consumption, a washing process is necessary to remove most of the bitter saponins found in the seeds, as this type of saponin is considered to be a serious antinutritional factor. For industrial scale‐up of this processing step, leaching behavior of the saponin is of crucial importance to find the best design parameters and the most cost‐effective process conditions. This helps reduce energy waste and optimize water flow rate in a continuous washing process. The present study used well‐known models to explain saponins' leaching kinetics from the quinoa seeds with water at different temperatures. The best mathematical model with its justification was also determined, which is generally the most economical way to proceed.
    Journal of Food Process Engineering 04/2013; 36(2). DOI:10.1111/j.1745-4530.2012.00673.x · 0.63 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The edible coating applied to food pieces prior to hot air drying is a technology that can improve the nutritional and sensory qualities of dehydrated products. The effects of the pectin coating technique on the drying efficiency and quality of papaya slices of the Formosa cultivar were investigated, determining the cell structure, color, and vitamin C contents of the fresh and dried fruits, with and without a pectin coating. The drying kinetics was evaluated based on Fick's Law. The analytical solution for a plane sheet was used to estimate the water effective diffusion coefficients, and, in order to take into account shrinkage during drying, the average and variable thicknesses were considered in an approximate manner. Diffusion modeling presented a better fit when considering the thickness of the slices as variable. Regarding fruit quality, the coating applied to papaya slices before drying enhances vitamin C retention in comparison to papaya dried without coating, showing that pectin coating efficiently prevented oxidation of this bioactive compound. In addition, the moisture diffusivity of the coated samples was higher than that of the non-coated slices, due to the hydrophilic nature of the pectin. Light and transmission electron microscopy images revealed intense rupturing of the cell membranes in the dried tissues. The cell tissue arrangement in the coated papaya slices was similar to that found in the fresh papaya slices, before and after drying.
    Food and Bioprocess Technology 10/2014; 7(10):2828-2839. DOI:10.1007/s11947-014-1350-6 · 3.13 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Rheological behavior and green color retention are important parameters during thermal processing of pureed leafy vegetables. In this study, an attempt was made to investigate thermal effect on the color and rheological characteristics of rocket (Eruca sativa L.) purees made from leaves with and without stems. The color degradation kinetics of rocket puree was studied at temperatures between 60 and 110 �C using fractional conversion technique. The degradation kinetics of puree followed a 1st order reaction kinetics and the activation energy values for puree with and without stems were ranged between 38.90 and 51.21 kJ/mol. Effects of blanching on oscillatory and steady flow rheology of puree made from leaves with and without stems were studied in the temperature range of 25 to 70 �C. All puree samples exhibited an elastic modulus that is larger than the loss modulus in the tested frequency range. Blanched leaf puree exhibited the highest mechanical strength at 70 �C. The steady flow data fitted the Herschel– Bulkley model well. The complex viscosity and the apparent viscosity at similar frequency and shear rate range failed to follow the Cox–Merz rule. Scanning electron microscopy and sieve-analysis revealed that the leaf puree had smaller particle sizes than puree with stems.
    Journal of Food Engineering 12/2013; 119(3):660-667. DOI:10.1016/j.jfoodeng.2013.06.038 · 2.58 Impact Factor

Full-text (3 Sources)

Available from
May 26, 2014