Sustained-release modeling of clove essential oil in brine to improve the shelf life of Iranian white cheese by bioactive electrospun zein.

In this study, the sustained-release of clove essential oil (CEO) loaded into the structure of electrospun zein was used as a biopreservative to extend the shelf life of Iranian white cheese. CEO was loaded at levels of 5, 7.5, and 10% w/w in the structure of electrospun nanofibers. In this study, a concentration of 35% w/v zein was used to produce electrospun fibers, and in the field emission scanning electron microscope (FESEM) it was observed that by increasing the loading of CEO from 5 to 10% w/w in the fiber structure, their diameter decreased from 517.96 ± 41.57 nm to 457.88 ± 32.45 nm. Although increasing the level of CEO reduced the diameter of the electrospun nanofibers, Young's modulus, tensile strength, and a higher level of CEO increased elongation at break of the films. The results of mechanical properties showed that by increasing the amount of CEO application in the structure of electrospun zein nanofibers from 5 to 10% w/w tensile strength from 8.18 ± 0.62 to 4.43 ± 0.86 MPa, and Young's modulus from 38.25 ± 2.81 to 27.25 ± 3.48 MPa decreased. Successful encapsulation of CEO in designed structures and the absence of adverse bonds between the encapsulant material (zein) and the core (CEO) were confirmed by the Fourier-transform infrared spectroscopy (FTIR) test. The in vitro sustained-release of the CEO in 8% w/v brine during 45 days of storage at 4 °C was modeled. The Fickian diffusion was the dominant release mechanism of the CEO and the Peppas-Sahlin model was the best model describing the essential oil release behavior. The electrospun films containing CEO were well able to suppress the growth of Listeria monocytogenes and Escherichia coli O157: H7 in samples of Iranian white cheese kept in 8% brine for 45 days at 4 °C. The samples treated with the electrospun film containing 7.5% w/w of CEO had the highest acceptability among different treatments.

Sustained release modeling of clove essential oil from the structure of starch-based bio-nanocomposite film reinforced by electrosprayed zein nanoparticles.

Electrosprayed zein nanoparticles containing 10% (w/w) of clove essential oil (CEO) were prepared and then with different levels (5, 10, and 15% w/w) in the starch matrix were used. The incorporation of zein nanoparticles in the structure of starch-based bio-nanocomposites films was confirmed by Fourier transform infrared spectroscopy and field emission scanning electron microscopy. Increasing the level of application of zein bio-nanofillers in the starch film matrix increased thickness and contact angle. However, the use of electrosprayed zein nanoparticles loaded by CEO (EZN-CEO) up to 10% significantly (p < 0.05) reduced the water vapor permeability (WVP), but using 15% of the nanoparticles increased the WVP of the films significantly (p < 0.05). Increasing the EZN-CEO up to 10% significantly (p < 0.05) increased the tensile strength and Young's modulus and reduced the elongation at break of the films. Sustained release of CEO from the bio-nanocomposites showed that the most release of the CEO occurs in 10% ethanol medium. The Fickian diffusion was the predominant mechanism in the release of the CEO, and the Peleg model was selected as the best one to explain the release behavior. The structures designed in this study can be used as an edible coating and bio-preservative in perishable food products.