Seyed-Ahmad Shahidi Articles List

List of Articles Seyed-Ahmad Shahidi

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1 - Modeling of Mass Transfer Kinetic During Osmotic Dehydration of Eggplant (Solanum Melongena L.)
A.A. Bahmani S.M. Jafari S.A. Shahidi

Introduction: The aim of this study is to investigate the effects of temperature, osmotic solution concentration and dehydration time on the mass transfer during osmotic dehydration of eggplant and then comparison of the mathematical models in order to select the best m More

Introduction: The aim of this study is to investigate the effects of temperature, osmotic solution concentration and dehydration time on the mass transfer during osmotic dehydration of eggplant and then comparison of the mathematical models in order to select the best model for the mass transfer. Materials and Methods: Dehydration of the eggplant with the osmotic solutions containing 5, 10 and 15% salt and temperatures of 30, 45 and 60°C in a water bath at the ratio of eggplant slices to osmotic solution of 1:10, 1:15 and 1: 20 has taken place. Water loss and solid gain values for each concentration and temperature at intervals of 0, 15, 30, 60, 90, 150, 210 and 270 minutes were determined respectively. Equilibrium values of water loss and solid gain were calculated by models as well as the rate of mass transfer. Results: The moisture content and mass transfer kinetics are functions of temperature and salt concentration changes over the time. The model proposed by some researchers (Azura model) with maximum Regression Coefficient and minimum root mean square error and the square sum error was compared to the Magee model that can describe the mass transfer kinetics better. The Azuara model in 1:15 ratio of osmotic solution of the sample resulted in a correlation coefficient of 0.9792 for water loss and of 0.9386 for solid gain as compared with 1:10 and 1:20 ratios that showed the best fit. Conclusion: The proposed model of Azuara regarding the maximum correlation and the minimum root mean square error and the sum of squared errors was recommended in order to model the mass transfer kinetics during osmotic dehydration of eggplant. Manuscript profile
Open Access Article
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2 - Modelling Kinetics of Thermal Colour Degradation in Production of Beetroot Juice Concentrate by Various Heating Methods
A. Ghorbani Hasan Saraei S. A. Shahidi M. Mohebbi R. Moaziyan

Introduction: Preservation of natural colour, as a quality attribute and characteristic ofbeetroot concentrate might be considered as a possibility if the knowledge of kinetic of colorchange is studied thoroughly.Materials and Methods: Three different heating/evaporatio More

Introduction: Preservation of natural colour, as a quality attribute and characteristic ofbeetroot concentrate might be considered as a possibility if the knowledge of kinetic of colorchange is studied thoroughly.Materials and Methods: Three different heating/evaporation processes were employed forthe production of beetroot juice concentrate. The juice was concentrated to a final 40 °Brixfrom an initial °Brix of 10 by microwave heating, rotary vacuum evaporator and evaporatingat atmospheric pressure.Results: The concentration of the final juice at 40 °Brix was achieved in 40, 43 and 70minutes by using microwave, rotary vacuum and atmospheric heating processes, respectively.The changes in colour during the concentration processes were investigated. Total colourdifferences (KE) and L, a and b parameters were used to estimate the extent of colour changesby using Hunter Lab equipment. All colour parameters were decreased with time. The zeroorder,first-order and a combined kinetics model were applied to the changes in colourparameters.Conclusion: The results indicated that the variation in TCD followed both first-order andcombined kinetics models, and parameters L, a and b followed only the combined model.This model implied that the colour formation and pigment destruction occurred duringconcentration processes of beetroot juice. Manuscript profile

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List of Articles Seyed-Ahmad Shahidi