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

Abstract

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.

Production and characterization of nanocapsules encapsulated linalool by ionic gelation method using chitosan as wall material

“…Encapsulation can also isolate a substance from the surrounding matter reactions (Matsuno & Adachi, 1993). Chitosan is an ideal polymeric shell component of oily nanocapsules because it has advantageous biological properties, such as biocompatibility (Khalid et al, 2006), biodegradability (Okamoto et al, 2002;Aguirre-Loredo et al, 2017), antimicrobial activity (Li et al, 2008), mucoadhesivity (Anitha et al, 2011), low toxicity (Chaparro-Hernández et al, 2015) and permeability enhancement (Tobío et al, 2000). Sodium tripolyphosphate is an anionic cross-linker; it exhibits non-toxicity and quick gelling ability that make it a favorable cross-linker for ionic gelation of chitosan (Kafshgari et al, 2011).…”

Spouted‐bed drying of acerola pulp (Malpighia emarginata DC): Effects of adding milk and milk protein on process performance and characterization of dried fruit powders

“…These data indicate that the drying adjuvants are responsible for influencing the water sorption characteristics of powdered formulations. Moreover, it can be seen that the addition of 1% concentrated whey‐protein to AMPWP formulation resulted in an increase of the parameter C, related to the water molar sorption energy difference between the monolayer and the upper layers (Aguirre‐Loredo, Rodriguez‐Hernandez, & Velazquez, ; Baptestini et al, ), which suggests that this drying adjuvant can be responsible for minimizing the interaction between the powder surface and the water molecules.…”

Effect of Transglutaminase Cross-Linking in Protein Isolates from a Mixture of Two Quinoa Varieties with Chitosan on the Physicochemical Properties of Edible Films

“…The constant C represents energy that is related to the difference in chemical potential of molecules adsorbed on the monolayer and superior sorption layers. K and C are temperature dependent constants that can be used to construct sorption isotherms at different temperatures [34]. The high value of C constant shows that water molecules are more strongly adsorbed onto matrix active sites [35], whereas K provides a measure of molecular interactions between the multilayers and adsorbent [36].…”