Theoretical Prediction of the Water Activity of Standard Saturated Salt Solutions at Various Temperatures

Kitic, D.; Jardim, D. C. P.; Favetto, Guillermo J.; Resnik, Silvia L.; Chirife, Jorge

doi:10.1111/j.1365-2621.1986.tb11227.x

Cited by 50 publications

(37 citation statements)

References 22 publications

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“…To assess the fitting of each model, the values of the R 2 and %E were calculated Adapted from: Alzamora et al (2003), Figura & Teixeira (2007) and Kitic et al (1986).…”

Section: Discussionmentioning

confidence: 99%

Modelling the effect of temperature on the water sorption isotherms of chitosan films

2016

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The interaction of the water molecules from the environment with foods and other materials can be evaluated using sorption isotherms. Films and biodegradable films are susceptible to changes in their functional characteristics due to adsorbed water. The amount of moisture that biodegradable films can adsorb depends on the temperature, relative humidity of the storage area and chemical composition. Several mathematical models can be used to describe the behavior of sorption isotherms in biodegradable films and some of them have been modified to include the temperature parameter into the equation. In this research, the original and modified BET, GAB, Halsey, Henderson and Dswin models were assessed to determine their suitability describing the behavior of moisture adsorption isotherms of chitosan films at 15, 20, 25 and 30 °C. The modified models of GAB, Dswin and Halsey gave the best fit to the experimental sorption data of the chitosan films, with R 2 values higher than 0.97 demonstrating that those models describe better the sorption isotherms at the temperatures studied.Keywords: chitosan film; moisture adsorption isotherm; GAB model. Practical Application:The knowledge of the relationship between the equilibrium moisture content, equilibrium relative humidity and temperature is very important in order to describe the effect of water activity on storage of foods. Several mathematical models were used to describe the water sorption behavior of chitosan edible films involving water activity, moisture content and temperature.

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“…To assess the fitting of each model, the values of the R 2 and %E were calculated Adapted from: Alzamora et al (2003), Figura & Teixeira (2007) and Kitic et al (1986).…”

Section: Discussionmentioning

confidence: 99%

Modelling the effect of temperature on the water sorption isotherms of chitosan films

2016

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“…NaCl, (NH 4 ) 2 SO 4 , KCl, BaCl 2 and K 2 SO 4 respectively. The preparation of each salt solution followed the procedure of Kitic et al (1986). As much as 200 g of salt was placed in a 5 l sorption container containing 200 l of distilled water.…”

Section: Preparation Of Saturated Salt Solutionsmentioning

confidence: 99%

Fungal Population of Nutmeg (Myristica fragrans) Kernels Affected by Water Activity During Storage

et al. 2018

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The aim of this investigation was to determine the effect of various water activities (a w ) on fungal population in nutmeg kernels during storage. The seed nutmegs were obtained from ripe fruits one week after they fell on the ground in North Minahasa Regency, North Sulawesi Province, Indonesia. The kernels (moisture content ± 10%) were stored 0, 15, and 30 days in various a w (0.75, 0.80, 0.83, 0.90, 0.97) using saturated salt solutions at 29 °C in sorption containers. Serial dilution method followed by a pour-plate method in Dichloran 18% Glycerol Agar (DG18) was used to isolate and quantify the fungal population. Results revealed that kernels stored at a w p < 0.05) different from at a w = 0.80-0.83. Fungal population of kernels determined a w p by duration of storage. Range of a w 0.80-0.83 has a smaller total fungal population than a w Aspergillus and Eurotium (6 species), Penicillium (3 species), Fusarium (2 species), 1 species each of Cladosporium or Syncephalastrum, and isolate A. The largest total fungal population (5.0×10 5 CFU g -1 ) was present at the beginning of storage (a w = 0.97) and it was dominated by Penicillium citrinum (2.6×10 5 CFU g -1 ) followed by Cladosporium cladosporioides (1.7×10 5 CFU g -1 ). After 30 days of storage (a w = 0.97) the population of P. citrinum was still dominant with a population of 2.4×10 4 CFU g -1 . Eurotium chevalieri followed with a population of 1.2×10 4 CFU g -1 .

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“…We therefore used our measured relationship between water activity and molality to determine the molality of a saturated solution. In order to do this we assume that water activity is independent of temperature, which is a good approximation for many aqueous solutions (Koop, 2004;Kitic et al, 1986). The calculated aqueous solubility at a number of temperatures for I 2 O 5 is given in Table 4.…”

Section: -50µmmentioning

confidence: 99%

Physical properties of iodate solutions and the deliquescence of crystalline I2O5 and HIO3

et al. 2010

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Abstract. Secondary aerosol produced from marine biogenic sources in algal-rich coastal locations will initially be composed of iodine oxide species, most likely I 2 O 5 , or its hydrated form HIO 3 , formed as a result of iodine gas-phase chemistry. At present, there is no quantitative hygroscopic data for these compounds and very little data available for iodate solutions (HIO 3 and I 2 O 5 share a common aqueous phase). With increased interest in the role of such aerosol in the marine atmosphere, we have conducted studies of (i) the deliquescence behaviour of crystalline HIO 3 and I 2 O 5 at 273-303 K, (ii) the efflorescence behaviour of aqueous iodate solution droplets, and (iii) properties (water activity, density, and viscosity) of subsaturated and saturated iodate solutions.The deliquescence of I 2 O 5 crystals at 293 K was observed to occur at a relative humidity (DRH) of 80.8±1.0%, whereas for HIO 3 , a DRH of 85.0±1.0% was measured. These values are consistent with measured water activity values for saturated I 2 O 5 and HIO 3 solutions at 293 K of 0.80±0.01 and 0.84±0.01 respectively. At all temperatures, DRH values for HIO 3 crystals were observed to be higher than for those of I 2 O 5 . The temperature-dependent DRH data, along with solubility and water activity data were used to evaluate the enthalpy of solution ( H sol ) for HIO 3 and I 2 O 5 . A H sol value of 8.3±0.7 kJ mol −1 was determined for HIO 3 which is consistent with a literature value of 8.8 kJ mol −1 . For I 2 O 5 , we report for the first time its solubility at various temperatures and H sol = 12.4±0.6 kJ mol −1 . The measured water activity values confirm that aqueous iodate solutions are strongly non-ideal, consistent with previous reports of complex ion formation and molecular aggregation.

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Theoretical Prediction of the Water Activity of Standard Saturated Salt Solutions at Various Temperatures

Cited by 50 publications

References 22 publications

Modelling the effect of temperature on the water sorption isotherms of chitosan films

Modelling the effect of temperature on the water sorption isotherms of chitosan films

Fungal Population of Nutmeg (Myristica fragrans) Kernels Affected by Water Activity During Storage

Physical properties of iodate solutions and the deliquescence of crystalline I<sub>2</sub>O<sub>5</sub> and HIO<sub>3</sub>

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Theoretical Prediction of the Water Activity of Standard Saturated Salt Solutions at Various Temperatures

Cited by 50 publications

References 22 publications

Modelling the effect of temperature on the water sorption isotherms of chitosan films

Modelling the effect of temperature on the water sorption isotherms of chitosan films

Fungal Population of Nutmeg (Myristica fragrans) Kernels Affected by Water Activity During Storage

Physical properties of iodate solutions and the deliquescence of crystalline I&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;5&lt;/sub&gt; and HIO&lt;sub&gt;3&lt;/sub&gt;

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Physical properties of iodate solutions and the deliquescence of crystalline I<sub>2</sub>O<sub>5</sub> and HIO<sub>3</sub>