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How does the barrier property of EVOH in the tray prevent oxygen ingress and extend the product's shelf life?

The barrier property of EVOH (Ethylene Vinyl Alcohol) in the tray is instrumental in preventing oxygen ingress and extending the shelf life of products. EVOH is a highly effective oxygen barrier material, characterized by its ability to impede the transmission of gases such as oxygen through the packaging material. Here's how it works:

High Oxygen Barrier: EVOH's exceptional oxygen barrier performance is attributed to its unique molecular structure. Comprising alternating ethylene and vinyl alcohol units, EVOH forms a highly crystalline structure with densely packed chains. This arrangement creates an effective barrier against oxygen molecules, significantly reducing their ability to permeate through the material. The polar nature of the vinyl alcohol units further enhances this barrier effect, as oxygen molecules have difficulty diffusing through the polymer matrix due to electrostatic interactions and hydrogen bonding. As a result, EVOH exhibits remarkably low oxygen transmission rates, making it an ideal choice for applications requiring stringent oxygen barrier properties, such as food packaging.

Oxygen Absorption: In addition to its inherent barrier function, EVOH possesses a unique ability to absorb oxygen molecules that manage to penetrate through the outer layers of the packaging. This oxygen scavenging capability is facilitated by the presence of residual hydroxyl groups within the polymer structure. When oxygen molecules diffuse into the EVOH matrix, they react with these hydroxyl groups, forming stable peroxy radicals. These radicals are then trapped within the polymer matrix, effectively removing oxygen from the surrounding environment. By continuously scavenging oxygen, EVOH helps maintain an oxygen-depleted atmosphere within the package, further inhibiting oxidative reactions and extending the shelf life of the enclosed products.

Preservation of Product Freshness: The barrier and oxygen scavenging properties of EVOH play a crucial role in preserving the freshness, flavor, and nutritional quality of packaged food products. Oxygen is a primary catalyst for various oxidative reactions that contribute to food deterioration, including lipid oxidation, protein denaturation, and vitamin degradation. By minimizing oxygen ingress and actively removing residual oxygen, EVOH Barrier Trays create a protective environment that significantly reduces the rate of these degradation processes. As a result, packaged foods remain fresher, retain their original flavor profiles, and retain higher levels of essential nutrients throughout their shelf life. This not only enhances consumer satisfaction but also extends the marketability of the products by maintaining their sensory appeal and nutritional value over time.

Protection Against External Factors: In addition to its role in oxygen barrier properties, EVOH provides effective protection against a range of other external factors that can impact product quality. Its low moisture vapor transmission rate helps prevent moisture loss or gain, preserving the texture, consistency, and overall quality of moisture-sensitive food products. EVOH acts as a barrier to light, particularly in the ultraviolet (UV) spectrum, which can induce photochemical reactions bring about color fading, flavor changes, and nutrient degradation. By blocking UV radiation, EVOH helps maintain the visual appeal and nutritional integrity of packaged foods. Its ability to block odors ensures that the sensory attributes of the enclosed products remain unaffected by external aromas, preventing flavor contamination and preserving the intended flavor profiles.

Moisture rention tray