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Mohammad Shafiur Rahman - One of the best experts on this subject based on the ideXlab platform.
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State Diagram of Crystallized Date-Syrup: Freezing Curve, Glass Transition, Crystals-Melting and Maximal-Freeze-Concentration Condition
Thermochimica Acta, 2018Co-Authors: Kutaila Abbas Al-farsi, Nasser Al-habsi, Mohammad Shafiur RahmanAbstract:ABSTRACT State Diagram of crystallized date-syrup was developed based on the freezing curve, glass transition curve, sugar crystals-melting curve, maximal-freeze-concentration condition, and eutectic point. The freezing point, glass transition, and sugar crystal-melting curves were modeled by Chen’s model based on Clausius-Clapeyron equation, Gordon-Taylor equation and Flory-Huggins equation, respectively. The ultimate maximal-freeze-concentration condition was determined as -42.8 °C [i.e. (Tm′)u, end point of freezing curve]. The intersection point on the freezing curve from the vertical line passing through the end point of freezing [i.e. (Tm′)u] as Xs′ [i.e. 0.73 g/g sample (i.e. un-freezable water as 0.27 g/g sample)]. The eutectic temperature and solutes content at eutectic point were determined as -10.2 °C and 0.39 g/g sample, respectively.
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thermal characteristics and State Diagram of freeze dried broccoli freezing curve maximal freeze concentration condition glass line and solids melting
Thermochimica Acta, 2017Co-Authors: Sithara Suresh, Nejib Guizani, Nasser Alhabsi, Mohammad Shafiur RahmanAbstract:Abstract Stability of foods during processing and storage can be determined from their phase and State Diagrams. In this study, State Diagram of broccoli was developed considering freezing curve, glass line, maximal-freeze-concentration conditions, solids-melting and BET-monolayer line. The freezing point, glass transition and solids-melting were measured and modeled by Chen’s model, Gordon-Taylor model, and Flory-Huggins model, respectively. The ultimate maximal-freeze-concentration conditions ( T m ′) u (i.e. end temperature of freezing) and ( T g ′′′) u [i.e. end glass transition at ( T m ′) u ] were found as −30.0 °C and −32.2 °C, respectively, and solids content (i.e. X s ′) at this point was 0.70 g/g sample. The solids-water interaction (χ) during melting was estimated as 0.69 (dimensionless) from Flory-Huggins model, and BET-monolayer was observed as 0.089 g/g dry-solids at 20 °C.
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exploring validity of the macro micro region concept in the State Diagram browning of raw and freeze dried banana slices as a function of moisture content and storage temperature
Journal of Food Engineering, 2017Co-Authors: Mohammad Shafiur Rahman, Ghalib Said AlsaidiAbstract:Abstract State Diagram (i.e. 12 micro-regions) of ripe banana was mapped by measuring and modeling its freezing point, glass transition, maximal-freeze-concentration conditions, solids-melting, and BET-monolayer. At 20 °C, the BET-monolayer moisture was observed as 0.044 g/g dry-solids, and decreased with the increase of temperature. Un-freezable water was found as 0.26 g/g sample and the maximal-freeze-concentration temperature ( T m ′) was observed as −34.5 °C. The freezing point and solids-melting peak were modeled by Chen’s and Flory-Huggins models, respectively. Browning of banana stored at different moisture and temperature (i.e. at different micro-regions) were measured as a function of storage time and modeled with first order reaction kinetics. The variation of reaction rate constant was analyzed based on the glass transition, water activity and macro-micro region concepts. At a specific moisture content, reaction rate constant showed a shift (i.e. sample containing freezable water) or change in slope (i.e. sample containing un-freezable water), when plotted as a function of temperature. However, it was difficult to find any validity above or below glass transition (or BET-monolayer) when all data points (i.e. all moisture and temperature) were plotted (i.e. rate constant with moisture or temperature). Arrhenius plot at moisture content 0.04 g/g sample showed two linear regions (i.e. below and above critical temperature 45 °C) with activation energy values of 105.3 and 25.1 kJ/mol, respectively. Universal validation was difficult to achieve, thus the rate constants within different micro-regions were empirically correlated with moisture content, storage temperature, BET-monolayer and glass transition temperature (p
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development of State Diagram of bovine gelatin by measuring thermal characteristics using differential scanning calorimetry dsc and cooling curve method
Thermochimica Acta, 2010Co-Authors: Mohammad Shafiur Rahman, Nejib Guizani, Ghalib Said Alsaidi, Aminah AbdullahAbstract:A State Diagram of bovine gelatin was developed by measuring the freezing curve, glass transition, unfolding, solids-melting lines, and ultimate maximum-freeze-concentration conditions. The freezing point decreased with the increase of solids; whereas glass transition, unfolding, and solids-melting decreased with the decrease of solids up to solids content 0.84 g/g gelatin and then remained constant. The freezing point, glass transition and solids-melting were modeled by Chen’s model based on the Clausius-Clapeyron equation, modified Gordon-Taylor model, and Flory’s equation, respectively. The ultimate maximumfreeze-concentration conditions were found as (T � m)u equal to −11.9 ◦ C and (T ��� g ) u equal to −14.9 ◦ C, and the characteristic solids content, X
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food stability determination by macro micro region concept in the State Diagram and by defining a critical temperature
Journal of Food Engineering, 2010Co-Authors: Mohammad Shafiur RahmanAbstract:Abstract In the 1950s the concept of water activity was proposed for determining food stability. This concept is now being used although it has some limitations. Indeed, these limitations mean that the concept is not universally applicable and in fact is invalid under certain conditions. In order to address the limitations of the water activity concept, the glass transition concept was proposed in the 1960s, although significant application of the concept only started in the 1980s. Recently, it has become evident that the glass transition concept is also not universally valid for stability determination in all types of foods when stored under different conditions. Currently in the literature the need is emphasized to combine the water activity and glass transition concepts since both concepts could complement each other. The glass transition concept was used to develop the State Diagram by drawing another stability map using freezing curve and glass transition line. In this paper an attempt is made to review the published methods used to combine both concepts. These approaches are graphical plot of glass transition conditions and water content as a function of water activity, and macro–micro region concept in the State Diagram. In addition, a new approach is proposed in this paper by defining a critical temperature for stability and then relating it with water content, and other hurdles affecting food stability. The water mobility concept is also reviewed to provide another dimension of food stability in order to determine a more complete picture.
Shafiur M Rahman - One of the best experts on this subject based on the ideXlab platform.
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State Diagram of freeze dried garlic powder by differential scanning calorimetry and cooling curve methods
Journal of Food Science, 2005Co-Authors: Shafiur M Rahman, Shyam S Sablani, Nasser Alhabsi, S Almaskri, R AlbelushiAbstract:zable water zable water zable water zable water, and the G , and the G , and the G , and the G , and the Gordon-Taylor model, r aylor model, r aylor model, r aylor model, r aylor model, respectively. Maximal-freeze-concentrated condition was found ated condition was found ated condition was found ated condition was found ated condition was found as as as as X X X X X w (character acter acter acteristic water content) = 0.82 ( istic water content) = 0.82 ( istic water content) = 0.82 ( istic water content) = 0.82 ( istic water content) = 0.82 (X s (characteristic solids content) = 0.18) with the char istic solids content) = 0.18) with the char istic solids content) = 0.18) with the char istic solids content) = 0.18) with the char istic solids content) = 0.18) with the characteristic tem- istic tem- istic tem- istic tem- istic tem- per per per
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State Diagram of date flesh using differential scanning calorimetry dsc
International Journal of Food Properties, 2004Co-Authors: Shafiur M RahmanAbstract:Abstract The State Diagram of date flesh was developed by measuring its freezing points, glass transition temperatures, maximal-freeze-concentration condition ( and ), and solute melting points (or decomposition temperature) by Differential Scanning Calorimetry (DSC). The freezing curve and glass transition lines were developed using Clausius-Clapeyron equation by incorporating concept of unfrozen water, and Gordon-Taylor equation, respectively. The developed State Diagram of date flesh can be used in determining its stability during storage as a function of temperature and moisture content (such as, frozen and dried conditions) as well as in designing drying and freezing processes.
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State Diagram of tuna meat freezing curve and glass transition
Journal of Food Engineering, 2003Co-Authors: Shafiur M Rahman, Nejib Guizani, Stefan Kasapis, Omar Saud AlamriAbstract:Abstract The State Diagram of tuna meat was developed by measuring and modeling its glass transition temperatures and freezing points. Fresh tuna meat was dried in a freeze drier to vary the moisture content from 73.3% to 6.0% (wet basis). Small deformation dynamic oscillation was employed to identify changes in the viscoelastic properties of tuna as a function of solids. Cooling curve method was used to measure the freezing point and end point of freezing. The State Diagram yielded maximally freeze-concentrated solutes at 61% solids with the characteristic temperature of glass formation being −54.2 °C. The freezing curve and glass transition lines were developed using the Clausius–Clapeyron equation adjusted with unfreezable water and Gordon–Taylor model, respectively.
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State Diagram of apple slices glass transition and freezing curves
Food Research International, 2001Co-Authors: Yan Bai, Shafiur M Rahman, Conrad O Perera, Bronwen G Smith, Laurence D MeltonAbstract:Abstract The State Diagram of apple flesh was developed by measuring and modeling its freezing points and glass transition temperatures. The freezing curve and glass transition lines were developed using Clausias–Clapeyron and Gordon–Taylor models, respectively. The State Diagram of apple pieces developed in this work can be used in determining the stability during frozen storage and in dried conditions as well as in designing drying and freezing processes.
Nejib Guizani - One of the best experts on this subject based on the ideXlab platform.
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thermal characteristics and State Diagram of freeze dried broccoli freezing curve maximal freeze concentration condition glass line and solids melting
Thermochimica Acta, 2017Co-Authors: Sithara Suresh, Nejib Guizani, Nasser Alhabsi, Mohammad Shafiur RahmanAbstract:Abstract Stability of foods during processing and storage can be determined from their phase and State Diagrams. In this study, State Diagram of broccoli was developed considering freezing curve, glass line, maximal-freeze-concentration conditions, solids-melting and BET-monolayer line. The freezing point, glass transition and solids-melting were measured and modeled by Chen’s model, Gordon-Taylor model, and Flory-Huggins model, respectively. The ultimate maximal-freeze-concentration conditions ( T m ′) u (i.e. end temperature of freezing) and ( T g ′′′) u [i.e. end glass transition at ( T m ′) u ] were found as −30.0 °C and −32.2 °C, respectively, and solids content (i.e. X s ′) at this point was 0.70 g/g sample. The solids-water interaction (χ) during melting was estimated as 0.69 (dimensionless) from Flory-Huggins model, and BET-monolayer was observed as 0.089 g/g dry-solids at 20 °C.
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development of State Diagram of bovine gelatin by measuring thermal characteristics using differential scanning calorimetry dsc and cooling curve method
Thermochimica Acta, 2010Co-Authors: Mohammad Shafiur Rahman, Nejib Guizani, Ghalib Said Alsaidi, Aminah AbdullahAbstract:A State Diagram of bovine gelatin was developed by measuring the freezing curve, glass transition, unfolding, solids-melting lines, and ultimate maximum-freeze-concentration conditions. The freezing point decreased with the increase of solids; whereas glass transition, unfolding, and solids-melting decreased with the decrease of solids up to solids content 0.84 g/g gelatin and then remained constant. The freezing point, glass transition and solids-melting were modeled by Chen’s model based on the Clausius-Clapeyron equation, modified Gordon-Taylor model, and Flory’s equation, respectively. The ultimate maximumfreeze-concentration conditions were found as (T � m)u equal to −11.9 ◦ C and (T ��� g ) u equal to −14.9 ◦ C, and the characteristic solids content, X
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State Diagram of dates glass transition freezing curve and maximal freeze concentration condition
Journal of Food Engineering, 2010Co-Authors: Nejib Guizani, Mohammad Shafiur Rahman, Ghalib Said Alsaidi, Salwa Bornaz, Ahmed AlalawiAbstract:Abstract The State Diagram of Deglet Nour dates was developed using freezing curve, glass transition line, and maximal-freeze-concentration condition. Freezing points and glass transition temperature were measured by differential scanning calorimetry (DSC) as a function of water content. Freezing points were fitted to the Clausius–Clapeyron equation adjusted with un-freezable water, and glass transition was fitted to the Gordon–Taylor model. Glass transition decreased with a decrease in solids content, confirming the plasticizing effect of water on date solids. Freezing point data indicated the temperature when ice formed and dates would be most stable in terms of its deterioration if it can be stored below its glass transition. Maximum-freeze-concentration conditions was found as X s ′ (characteristic solids content) = 0.78 g/g sample, with the characteristic temperature as T g ′ (characteristics glass transition) = −48 °C and T m ′ (characteristic end point of freezing) = −38.2 °C. These characteristics indicated that 0.22 g/g sample water in date was un-freezable (i.e. bound with solids or unable to form ice). The developed State Diagram can be used in determining the stability of dates during storage as a function of temperature and moisture content. Moreover, it can be used to determine optimum drying and freezing conditions.
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State Diagram of tuna meat freezing curve and glass transition
Journal of Food Engineering, 2003Co-Authors: Shafiur M Rahman, Nejib Guizani, Stefan Kasapis, Omar Saud AlamriAbstract:Abstract The State Diagram of tuna meat was developed by measuring and modeling its glass transition temperatures and freezing points. Fresh tuna meat was dried in a freeze drier to vary the moisture content from 73.3% to 6.0% (wet basis). Small deformation dynamic oscillation was employed to identify changes in the viscoelastic properties of tuna as a function of solids. Cooling curve method was used to measure the freezing point and end point of freezing. The State Diagram yielded maximally freeze-concentrated solutes at 61% solids with the characteristic temperature of glass formation being −54.2 °C. The freezing curve and glass transition lines were developed using the Clausius–Clapeyron equation adjusted with unfreezable water and Gordon–Taylor model, respectively.
Qilong Shi - One of the best experts on this subject based on the ideXlab platform.
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thermal transition and State Diagram of yacon dried by combined heat pump and microwave method
Journal of Thermal Analysis and Calorimetry, 2015Co-Authors: Qilong Shi, Yaqin Zheng, Ya ZhaoAbstract:Adsorption isotherm and thermal transition of yacon dried by combined heat pump and microwave method were developed to investigate the interactions between water and biopolymers. Adsorption isotherm of yacon was determined by the gravimetric method, and the data were modeled by GAB model. The GAB monolayer moisture content was observed to be 0.0795 g H2O g−1 dry solids. Thermal transitions of yacon powders equilibrated at various water activities were analyzed using differential scanning calorimetry. The State Diagram was developed using glass transition line and freezing curve, which were modeled by Gordon–Taylor equation and Clausius–Clapeyron equation, respectively. The maximal-freeze-concentrated condition was estimated as the solid content of 0.706 g g−1 yacon with the glass transition temperature of −66.6 °C. The adsorption properties and State Diagram of yacon are useful in optimizing conditions of freezing and drying of yacon as well as in evaluating its storage stability as a function of moisture content and temperature.
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glass transition and State Diagram for freeze dried agaricus bisporus
Journal of Food Engineering, 2012Co-Authors: Qilong Shi, Xihai Wang, Ya Zhao, Zhongxiang FangAbstract:Sorption isotherms and State Diagram of freeze-dried Agaricus bisporus were developed to further investigate the connection between the two distinct criteria of food stability. Sorption isotherms of freeze-dried A. bisporus were determined by the gravimetric method and the data were modeled by GAB model. The GAB monolayer moisture content was calculated to be 6.2 g/100 g (d.b.). The glass transition temperature of freeze-dried A. bisporus was determined by differential scanning calorimetry. The State Diagram was composed of the freezing curve and glass transition line, which were fitted according to Clausius–Clapeyron model and Gordon–Taylor model, respectively. The State Diagram yielded maximally-freeze-concentrated solutes at 0.704 solids with the characteristic temperature of glass formation being −77.9 °C. The State Diagram and sorption isotherms of freeze-dried A. bisporus are useful in evaluating the storage stability as a function of temperature and moisture content as well as optimizing drying and freezing conditions.
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glass transition and State Diagram for freeze dried horse mackerel muscle
Thermochimica Acta, 2009Co-Authors: Qilong Shi, Ya Zhao, Haihua Chen, Changhu XueAbstract:Abstract Glass transition temperatures of freeze-dried horse mackerel muscle conditioned at various water activities at 25 °C were determined by differential scanning calorimetry (DSC). High moisture content (>0.33 g/g, d.b.) samples obtained by adding liquid water into freeze-dried samples, were also analyzed. The State Diagram was composed of the freezing curve and the glass transition line, which were fitted according to Clausius–Clapeyron model and Gordon–Taylor model, respectively. The State Diagram yielded maximally freeze-concentrated solutes at 0.786 solids with the characteristic temperature of glass formation being −83.1 °C. The State Diagram of horse mackerel muscle developed in this work could be used to predict the stability during frozen storage and in dried conditions as well as in designing drying and freezing processes.
Ghalib Said Alsaidi - One of the best experts on this subject based on the ideXlab platform.
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exploring validity of the macro micro region concept in the State Diagram browning of raw and freeze dried banana slices as a function of moisture content and storage temperature
Journal of Food Engineering, 2017Co-Authors: Mohammad Shafiur Rahman, Ghalib Said AlsaidiAbstract:Abstract State Diagram (i.e. 12 micro-regions) of ripe banana was mapped by measuring and modeling its freezing point, glass transition, maximal-freeze-concentration conditions, solids-melting, and BET-monolayer. At 20 °C, the BET-monolayer moisture was observed as 0.044 g/g dry-solids, and decreased with the increase of temperature. Un-freezable water was found as 0.26 g/g sample and the maximal-freeze-concentration temperature ( T m ′) was observed as −34.5 °C. The freezing point and solids-melting peak were modeled by Chen’s and Flory-Huggins models, respectively. Browning of banana stored at different moisture and temperature (i.e. at different micro-regions) were measured as a function of storage time and modeled with first order reaction kinetics. The variation of reaction rate constant was analyzed based on the glass transition, water activity and macro-micro region concepts. At a specific moisture content, reaction rate constant showed a shift (i.e. sample containing freezable water) or change in slope (i.e. sample containing un-freezable water), when plotted as a function of temperature. However, it was difficult to find any validity above or below glass transition (or BET-monolayer) when all data points (i.e. all moisture and temperature) were plotted (i.e. rate constant with moisture or temperature). Arrhenius plot at moisture content 0.04 g/g sample showed two linear regions (i.e. below and above critical temperature 45 °C) with activation energy values of 105.3 and 25.1 kJ/mol, respectively. Universal validation was difficult to achieve, thus the rate constants within different micro-regions were empirically correlated with moisture content, storage temperature, BET-monolayer and glass transition temperature (p
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development of State Diagram of bovine gelatin by measuring thermal characteristics using differential scanning calorimetry dsc and cooling curve method
Thermochimica Acta, 2010Co-Authors: Mohammad Shafiur Rahman, Nejib Guizani, Ghalib Said Alsaidi, Aminah AbdullahAbstract:A State Diagram of bovine gelatin was developed by measuring the freezing curve, glass transition, unfolding, solids-melting lines, and ultimate maximum-freeze-concentration conditions. The freezing point decreased with the increase of solids; whereas glass transition, unfolding, and solids-melting decreased with the decrease of solids up to solids content 0.84 g/g gelatin and then remained constant. The freezing point, glass transition and solids-melting were modeled by Chen’s model based on the Clausius-Clapeyron equation, modified Gordon-Taylor model, and Flory’s equation, respectively. The ultimate maximumfreeze-concentration conditions were found as (T � m)u equal to −11.9 ◦ C and (T ��� g ) u equal to −14.9 ◦ C, and the characteristic solids content, X
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State Diagram of dates glass transition freezing curve and maximal freeze concentration condition
Journal of Food Engineering, 2010Co-Authors: Nejib Guizani, Mohammad Shafiur Rahman, Ghalib Said Alsaidi, Salwa Bornaz, Ahmed AlalawiAbstract:Abstract The State Diagram of Deglet Nour dates was developed using freezing curve, glass transition line, and maximal-freeze-concentration condition. Freezing points and glass transition temperature were measured by differential scanning calorimetry (DSC) as a function of water content. Freezing points were fitted to the Clausius–Clapeyron equation adjusted with un-freezable water, and glass transition was fitted to the Gordon–Taylor model. Glass transition decreased with a decrease in solids content, confirming the plasticizing effect of water on date solids. Freezing point data indicated the temperature when ice formed and dates would be most stable in terms of its deterioration if it can be stored below its glass transition. Maximum-freeze-concentration conditions was found as X s ′ (characteristic solids content) = 0.78 g/g sample, with the characteristic temperature as T g ′ (characteristics glass transition) = −48 °C and T m ′ (characteristic end point of freezing) = −38.2 °C. These characteristics indicated that 0.22 g/g sample water in date was un-freezable (i.e. bound with solids or unable to form ice). The developed State Diagram can be used in determining the stability of dates during storage as a function of temperature and moisture content. Moreover, it can be used to determine optimum drying and freezing conditions.
