Development of active films with thymol-based hydrophobic eutectic solvents.

Area of Science:

• Food Science and Technology
• Materials Science
• Biochemistry

Background:

• Gelatin films are widely used but often lack mechanical strength and stability.
• Natural eutectic solvents (NAES) offer potential for improving biopolymer-based film properties.
• Thymol, a natural antimicrobial, can be incorporated into NAES to impart bioactivity.

Purpose of the Study:

• To investigate the influence of hydrophobic natural eutectic solvents (NAES) composed of thymol, acetic acid, betaine, and caprylic acid on the properties of bovine gelatin films.
• To evaluate the mechanical performance, physical properties, stability, and antimicrobial activity of these modified gelatin films.
• To assess the potential of NAES-based gelatin films for active packaging applications.

Main Methods:

• Bovine gelatin films were prepared with varying concentrations of NAES (acetic acid, betaine, caprylic acid).
• Mechanical properties (tensile strength, elongation at break), water vapor permeability, total soluble matter, and swelling were analyzed.
• Volatility of thymol and NAES was assessed, and antibacterial activity against Gram-positive and Gram-negative bacteria was evaluated.
• The efficacy of NAES-based films in reducing microbial contamination on chicken breast was tested.

Main Results:

• NAES significantly enhanced the mechanical properties of gelatin films, with notable increases in tensile strength and elongation at break.
• Films incorporating NAES exhibited reduced water vapor permeability, lower soluble matter, and decreased swelling.
• NAES dramatically reduced the volatility of thymol, improving the stability of the active compounds.
• The developed films displayed significant antibacterial activity, achieving large inhibition zones and undetectable CFU levels for key pathogens on chicken breast.

Conclusions:

• Hydrophobic NAES effectively plasticize and reinforce bovine gelatin films.
• NAES-based gelatin films demonstrate improved physical properties and enhanced stability, particularly regarding thymol volatility.
• These films possess potent antimicrobial properties, making them promising candidates for active food packaging solutions.
• The study highlights the potential of NAES as functional additives for developing advanced biodegradable packaging materials.