Ideal food packaging materials should possess good water vapor barrier properties, oxygen barrier properties, thermal stability, antibacterial properties, mechanical properties, and anti-fogging properties, and should not be easily affected by environmental factors. Polyethylene (PE) is the most common and widely used plastic packaging material, with high transparency, easy processing, long storage time, and low cost, accounting for 40% of the entire plastic packaging. However, materials like polyethylene exhibit hydrophobicity, leading to fogging issues, directly impacting their applications.
In recent years, anti-fogging materials have become a research focus, capturing the interest of packaging researchers and manufacturers across various industries. Methods to improve the anti-fogging performance of polymers include melt blending, irradiation, and surface coating. Research on the preparation methods of anti-fog films mainly focuses on surface attachment and internal blending. Surface attachment involves applying an anti-fogging agent to the film surface, offering simplicity but limited resistance to scrubbing and a finite anti-fogging time. Internal blending involves incorporating an anti-fogging agent into the resin matrix for extrusion, resulting in films with longer anti-fogging time and superior anti-fogging effects compared to coating methods.
Polyglyceryl Fatty Acid Ester (PGFE, C27H54O8) is a non-ionic surfactant with high safety and wide applications in the production of pharmaceuticals, food, and cosmetics. Additionally, PGFE serves as an antistatic agent, lubricant, anti-fogging agent, and plasticizer for polyolefin resins, providing multiple functionalities, including antibacterial and preservative properties.
One of the new trends in functional food packaging is the incorporation of food antimicrobial agents and antioxidants into films. Antimicrobial packaging reduces direct contact between food and chemicals, enhancing food safety and quality. Antimicrobial active packaging films act as carriers for controlled release of antimicrobial substances during food storage, including essential oils, lysozyme, carboxymethyl cellulose, and chitosan.
Sodium Dehydroacetate (DHA-S, C8H7NaO4) is a novel food preservative with strong inhibitory effects on yeast, mold, and bacteria. Studies show that DHA-S degrades gradually into acetic acid in water, posing no harm to humans and preserving the flavor and taste of food. Calcium Propionate (CP, (CH3CH2COO)2Ca) is a common inorganic antifungal agent used in food and feed. Research indicates that CP-modified polyvinyl alcohol packaging films exhibit inhibitory effects on bacteria when CP mass fraction is 0.025 g/mL. Both DHA-S and CP are approved by the Food and Agriculture Organization (FAO) and the World Health Organization (WHO) as safe food preservatives.