Measurement of Water Activity, Moisture Sorption Isotherm, and Moisture Content of Foods

2020 ◽  
pp. 207-226
Author(s):  
Anthony J. Fontana ◽  
Brady P. Carter
Keyword(s):  
Moisture Content ◽  
Water Activity ◽  
Sorption Isotherm ◽  
Moisture Sorption ◽  
Moisture Sorption Isotherm

scholarly journals Moisture sorption isotherm and thermodynamic properties of jamun (Syzygium cumini L.) powder made from jamun pulp and seed

2019 ◽  
Vol 8 (1) ◽  
Author(s):  
Indira Dey Paul ◽  
Madhusweta Das
Keyword(s):  
Moisture Content ◽  
Sorption Isotherm ◽  
Moisture Sorption ◽  
Isosteric Heat ◽  
Integral Enthalpy ◽  
Seed Kernel ◽  
Syzygium Cumini ◽  
Spreading Pressure ◽  
Hot Air ◽  
Moisture Sorption Isotherm

The present work aimed to: i) find the suitable proportion, based on sensory evaluation, of microwave-convective hot air dried jamun (Syzygium cumini L.) pulp and seed kernel powder to be mixed for the preparation of jamun powder (JP); ii) generate and model the moisture sorption isotherm (MSI) of JP; and iii) estimate net isosteric heat of sorption (qst), spreading pressure (φ), net integral enthalpy (Qin), and net integral entropy (Sin). To formulate JP, the proportion (w/w, db) comprising 2% kernel and 98% pulp powder was the most desirable. The Peleg model was the best fit to MSI of JP. The qst decreased following linear relationship from 11.02 kJ. mol-1 at 5% equilibrium moisture content (EMC) to 0.27 kJ. mol-1 at 30% EMC. The φ increased with increase in water activity and decreased with increase in temperature from 25 ºC to 35 ºC, and the values of φ at 45 ºC were even higher than at 25 ºC. Net integral enthalpy (Qin) initially decreased till 6% moisture content in JP and displayed an increasing trend with further increase in moisture content. On the contrary, Sin, kept on decreasing continually with increasing moisture content. The moisture zone of 7-11% was considered safe for storage for storage of JP within the temperature range of 45-25 ºC.

scholarly journals MATHEMATICAL MODELS AND THERMODYNAMIC PROPERTIES OF MOISTURE SORPTION ISOTHERMS OF FERMENTED CASSAVA FLOUR BY RED YEAST RICE

2017 ◽  
Vol 13 (1) ◽  
pp. 29 ◽  
Author(s):  
Mutiara Nur Alfiah ◽  
Sri Hartini ◽  
Margareta Novian Cahyanti
Keyword(s):  
Thermodynamic Properties ◽  
Moisture Content ◽  
Sorption Isotherm ◽  
Moisture Sorption ◽  
Red Yeast Rice ◽  
Cassava Flour ◽  
Red Yeast ◽  
Moisture Sorption Isotherm ◽  
Gab Model ◽  
Monolayer Moisture

<p>This research aims to determine moisture sorption isotherm curves, moisture sorption isotherm models and thermodynamic properties of fermented cassava flour by red yeast rice. The moisture sorption isotherm model used are Guggenheim Anderson deBoer (GAB), Brunauer Emmet Teller (BET) and Caurie. Meanwhile, the test of modelling accuray by Mean Relative Deviation (MRD) and Root Mean Square Error (RMSE). The thermodynamic properties, i.e., enthalpy and entropy were calculated by Clausius - Clapeyron equation. The result shows that the moisture sorption isotherm curve on fermented cassava flour in a sigmoid form (type II). The GAB model is the best model for moisture sorption isotherm of fermented cassava flour by red yeast rice. The MRD and RMSE values at 30˚C, 35˚C and 40˚C are 3.12%, 2.71%, 3.81%, and 1.01, 0.35, 0.42, respectively. The monolayer moisture content at 30˚C, 35˚C and 40˚C are 6.61%, 6.27% and 6.91%, based on GAB model. Meanwhile, when the BET model was used, the monolayer moisture content are 4.92%, 4.86% and 5.19%, while by Caurie model are 6.37%, 6.18% and 5.30%, at 30˚C, 35˚C and 40˚C, respectively. The enthalpy and entropy of water sorption process were decreased when moisture content increased.</p>

scholarly journals Drying kinetics and determination of water sorption isotherms of corn

2017 ◽  
Vol 15 (2) ◽  
Author(s):  
J Roy ◽  
MA Alim ◽  
MN Islam
Keyword(s):  
Moisture Content ◽  
Sorption Isotherm ◽  
Water Sorption ◽  
Sorption Isotherms ◽  
Moisture Sorption ◽  
Drying Kinetics ◽  
Drying Time ◽  
Moisture Sorption Isotherm ◽  
Water Sorption Isotherm ◽  
Monolayer Moisture

The study was carried out for the purpose of determining the drying kinetics as well as moisture sorption isotherm of hybrid-81 corn. Corn at about 31% moisture content (wb) was dried in a forced convective hot air cabinet dryer at different drying conditions, such as variable air dry bulb temperature (40°C, 50°C and 60°C) and loading density (3.56 kg/m2, 7.12 kg/m2, and 10.68 kg/m2) as well as in shining sun at different layers (3.56 kg/m2, 7.12 kg/m2, and 10.68 kg/m2). The water sorption isotherm of the dried corn was developed using vacuum desiccators, which contained saturated salt solutions in the range of 11-93% RHs. The mono-layer moisture content calculated by the Brunauer–Emmett–Teller (BET) model (6.76 g/100 g solid) was lesser than that calculated by the Guggenheim–Anderson–De Boer (GAB) model (10.53 g/100 g solid). The energy constants were 10.45 and 4.64 as per BET and GAB equation, respectively. Both models gave suitable fits for corn. The activation energy (Ea) for diffusion of water was found to be 11.09 kcal/gm-mole for corn. Furthermore, it was noticed that, with the increase of corn layer, the drying rate decreased in case of both sun and mechanical drying. However, higher loading density resulted in efficient drying, at least up to 10.7 kg/m2. It was shown that the drying time to obtain stability was the lowest for moisture content (12.08 %) corresponding to aw of 0.65 in case of BET or GAB monolayer moisture content. This finding could be helpful in predicting the storage life of corn.J. Bangladesh Agril. Univ. 15(2): 309-317, December 2017

scholarly journals Measurement and Modelling of Moisture Sorption Isotherm and Heat of Sorption of Fresh Feces

Water ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 323
Author(s):  
Claire Remington ◽  
Catherine Bourgault ◽  
Caetano C. Dorea
Keyword(s):  
Moisture Content ◽  
Sorption Isotherm ◽  
Waste Treatment ◽  
Moisture Sorption ◽  
Activity Levels ◽  
Public Health Perspective ◽  
Heat Of Sorption ◽  
Moisture Sorption Isotherm ◽  
Fecal Sludge ◽  
Fresh Feces

The drying (or dewatering) of fresh feces and fecal sludge is a productive step in the management of sanitation, waste treatment, and resource recovery services. An improved understanding of fresh feces and fecal sludge drying would contribute to the development and deployment of fecal sludge management services. However, there is a lack of available literature on the fundamental drying characteristics of fresh feces. In response to this gap, this work shares experimental results for equilibrium moisture content of fresh feces at different water activity levels (aw) and proposes the use of the Guggenheim, Anderson, and de Boer (GAB) model for predicting aw, calculating the heat of sorption, and estimating the corresponding energy requirements for drying of fresh feces. This is the first time this work has been done with fresh feces. The total heat of evaporation was significant up to a moisture content of about 0.2 kg water per kg dry solids. In addition to informing drying process design, the sorption isotherm can be used to predict microbial activity, which could improve the management of feces and fecal sludge from a public health perspective. These data in turn will be used to promote access to dignified, safe, and sustainable sanitation.

scholarly journals Moisture Sorption Characteristics of Weaning Food

2020 ◽  
pp. 45-50
Author(s):  
Kabindra Bhattarai ◽  
Babita Adhikari ◽  
Prabina Ghimire
Keyword(s):  
Moisture Content ◽  
Sorption Isotherm ◽  
Dry Matter ◽  
Gravimetric Method ◽  
Moisture Sorption ◽  
Weaning Food ◽  
Sorption Data ◽  
Moisture Sorption Isotherm ◽  
Gab Model ◽  
Coefficient Of Regression

 Stickiness and caking are the significant problems for food powders due to moisture migration from the storage environment. This study was conducted to determine the moisture sorption isotherm of weaning food (Nutrilac and Superceral) and to fit the sorption data in different sorption isotherm models. Static gravimetric method was used to determine the equilibrium moisture content (EMC) at 22-89% RH at 30°C. The EMC data obtained were plotted to the models Brunauer Emmet Teller (BET), Guggenheim Anderson and De Boer (GAB). Results indicated that sorption isotherms were of type II isotherm according to Brunauer et al., (1940) classification. BET model was fitted to the sorption data with coefficient of regression 0.985 and 0.986 for Nutrilac and Supercereal respectively. The GAB model was fitted with coefficient of regression 0.983 and 0.979 for Nutrilac and Supercereal respectively. Monolayer moisture content determined from the BET and GAB model at 30°C were 1.63 and 2.24 g/100g dry matter for Nutrilac and 1.51 and 2.26 g/100g dry matter for Supercereal respectively.

scholarly journals MATHEMATICAL MODELS AND THERMODYNAMIC PROPERTIES OF MOISTURE SORPTION ISOTHERMS OF FERMENTED CASSAVA FLOUR BY RED YEAST RICE

2017 ◽  
Vol 13 (1) ◽  
pp. 29 ◽  
Author(s):  
Mutiara Nur Alfiah ◽  
Sri Hartini ◽  
Margareta Novian Cahyanti
Keyword(s):  
Thermodynamic Properties ◽  
Moisture Content ◽  
Sorption Isotherm ◽  
Moisture Sorption ◽  
Red Yeast Rice ◽  
Cassava Flour ◽  
Red Yeast ◽  
Moisture Sorption Isotherm ◽  
Gab Model ◽  
Monolayer Moisture

<p>This research aims to determine moisture sorption isotherm curves, moisture sorption isotherm models and thermodynamic properties of fermented cassava flour by red yeast rice. The moisture sorption isotherm model used are Guggenheim Anderson deBoer (GAB), Brunauer Emmet Teller (BET) and Caurie. Meanwhile, the test of modelling accuray by Mean Relative Deviation (MRD) and Root Mean Square Error (RMSE). The thermodynamic properties, i.e., enthalpy and entropy were calculated by Clausius - Clapeyron equation. The result shows that the moisture sorption isotherm curve on fermented cassava flour in a sigmoid form (type II). The GAB model is the best model for moisture sorption isotherm of fermented cassava flour by red yeast rice. The MRD and RMSE values at 30˚C, 35˚C and 40˚C are 3.12%, 2.71%, 3.81%, and 1.01, 0.35, 0.42, respectively. The monolayer moisture content at 30˚C, 35˚C and 40˚C are 6.61%, 6.27% and 6.91%, based on GAB model. Meanwhile, when the BET model was used, the monolayer moisture content are 4.92%, 4.86% and 5.19%, while by Caurie model are 6.37%, 6.18% and 5.30%, at 30˚C, 35˚C and 40˚C, respectively. The enthalpy and entropy of water sorption process were decreased when moisture content increased.</p>

scholarly journals Shelf Life Prediction of Chocomix Instant Chocolate Beverage Powder Using Accelerated Shelf Life Testing (ASLT) based on Critical Moisture Content Approach

REAKTOR ◽  
2018 ◽  
Vol 18 (2) ◽  
pp. 63 ◽  
Author(s):  
Rifa Nurhayati ◽  
Rosi Pratiwi ◽  
Baskara Katri Anandito ◽  
Ervika Rahayu Novita ◽  
Mukhammad Angwar
Keyword(s):  
Moisture Content ◽  
Shelf Life ◽  
Sorption Isotherm ◽  
Moisture Sorption ◽  
Value Added ◽  
Life Testing ◽  
Critical Moisture Content ◽  
Moisture Sorption Isotherm ◽  
Cocoa Products ◽  
Critical Moisture

Chocomix chocolate beverage powder is one of the increased value-added cocoa products by Griya Cokelat Nglanggeran. The aimed of this study to estimate the shelf life using Accelerated Shelf Life Testing (ASLT) based on critical moisture content. Results showed that critical moisture content of Chocomix was 4.01 % (db). Moisture sorption isotherm (MSI) curve of Chocomix at 28oC was type II isothermic sigmoidal with 2 curves at the ranged of water activity between 0.24 and 0.68; and the equation was  y = 86.584X3 – 91.893X2 + 28.818X – 0.470. The calculation showed that estimated shelf life of Chocomix stored in 51.89 µm thick package at 28oC was 16.4 months.Keywords: chocolate powder, critical moisture content, moisture sorption isotherm, shelf life

scholarly journals Study on water sorption isotherm of summer onion

2015 ◽  
Vol 40 (1) ◽  
pp. 35-51 ◽  
Author(s):  
Md Masud Alam ◽  
Md Nazrul Islam
Keyword(s):  
Moisture Content ◽  
Sorption Isotherm ◽  
Water Sorption ◽  
Moisture Sorption ◽  
Moisture Sorption Isotherm ◽  
Water Sorption Isotherm ◽  
Monolayer Moisture Content ◽  
Using Data ◽  
Monolayer Moisture ◽  
Added Salt

The water sorption characteristics of dehydrated onion and onion solutes composite by vacuum drying (VD) and air drying (AD) were developed at room temperature using vacuum desiccators containing saturated salt solutions at various relative humidity levels (11-93%). From moisture sorption isotherm data, the monolayer moisture content was estimated by Brunauer-Emmett-Teller (BET) and Guggenheim-Anderson-de Boer (GAB) equation using data up to a water activity of 0.52 and 0.93 respectively. Results showed that in case of non treated samples the monolayer moisture content values (Wo) of BET gave slightly higher values than GAB (9.7 vs 8.2) for VD, while GAB gave higher value than BET (11.0 vs 9.8) for AD. It is also seen that the treated and non treated onion slice and onion powder absorbed approximately the same amount of water at water activities below about 0.44 and above 0.44 the treated samples begin to absorb more water than the non treated samples. It was observed that 10-20% added of sugar gave no change in water sorption capacity while the amount of sorbed water increases with increasing amount added salt for mix onion product.Bangladesh J. Agril. Res. 40(1): 35-51, March 2015

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