Analysis and modeling of moisture sorption behavior for antimicrobial composite protein films

Abstract

The WPI-NaCas-GLY antimicrobial film takes full advantage of the controlled release of active or antimicrobial agents as well as demonstrates a great potential for functioning as an alternative biodegradable polymer in practical applications. The moisture sorption kinetics of the film as an important carrier of active agents was investigated at various relative humidities (RH). The results indicated that the moisture sorption characterization and procedure of this film can be described well by the empirical Peleg model with higher confidence and concordance. The model could predict the film's moisture content at any time (M t ), the time to reach any given level of R (t R ), the equilibrium moisture at any RH condition (M e ), and isotherm trend based upon experimental data and modeled constants k 1 , k 2 , a, b, c, and d without giving consideration to their physical meaning. The water vapor transmission rate of the WPI-NaCas-GLY antimicrobial film increased exponentially with increasing RH due to its hydrophilicity, which was primarily caused by the presence of glycerol in a higher content. The results also suggested that a w predominately affects the film's M e values compared with the temperature factor by fixed nonlinear multiple regression analyses.

Effects of whey protein films on the quality of thawed bigeye tuna (Thunnus obesus) chunks under modified atmosphere packaging and vacuum packaging conditions

“…The MA of the WPI films with 8% glycerol was more than twice that of the WPI films with 4% glycerol. Glycerol was added to the WPI films as a hydrophilic plasticizer usually to increase the elongation and flexibility of the films but also to stimulate an increase in MA, which verified the results of Yoshida et al [20] and Lei et al [13]. Figure 1 provides the changes in the TVC of tuna chunks during cold storage after frozen storage.…”

“…The moisture absorption (MA) was determined according to the modified version of the method suggested by Lei et al [13] and Zolfi et al [14]. Film specimens (20 mm 9 20 mm) were thoroughly dried in an air blow oven at 50°C for 24 h. After weighing, the dried sheets of film were placed in a desiccator containing calcium nitrite saturated solution at 25°C to ensure a RH of 55%.…”

Chitosan nanoparticles for enhancing drugs and cosmetic components penetration through the skin

“…At some stage, there seems to be a "boost" in moisture content probably due to the very high difference in pressure between the nanoparticles and the water surroundings at the initial stage of water sorption activity [36]. The rate of water sorption declined as the moisture content in the particles increased [37]. In general, moisture content of the NPs reached a plateau when the moisture content of the nanoparticles became in equilibrium with the relative humidity surrounding the NPs.…”

Water Sorption and Mechanical Properties of Starch/Chitosan Nanoparticle Films

“…At some stage, there seems to be a "shoot" in moisture content probably due to the very high difference in pressure between the film and the water surroundings at the initial stage of water sorption activity. Then, the rate of water sorption declined with time as the moisture content inside the film was increased [30]. In general, moisture content of the films then reached a plateau indicating that moisture content of the films became equilibrium with the relative humidity [12].…”

“…Besides, the effect of temperature on water sorption activity of the films can also be observed from the value of equilibrium moisture content of starch and starch/CNP films at different temperatures. According to Lei et al [30], temperature influences the binding characteristic of water molecules in the film matrix. It can be observed from Figures 2(a)-2(f) that the amount of equilibrium moisture content for both starch and starch/CNP films at 75% RH and temperature of 4°C was the highest followed by at 75% RH and temperatures of 30°C and 40°C.…”