On the shelves overflowing with snacks, vacuum-packed nuts attract a lot of attention with their unique packaging. Behind this seemingly simple packaging lies a series of sophisticated industrial technologies and industry considerations.
The core of vacuum packaging lies in creating a "vacuum." The process involves removing air from a sealed container to achieve a highly low-pressure state inside. For nuts, this step is critical, as oxygen is the primary culprit behind quality deterioration. It not only triggers oil oxidation, leading to rancidity, but also provides the necessary conditions for mold and insect eggs to survive. By creating a low-oxygen or even oxygen-free environment, these changes can be significantly delayed.
To achieve an effective vacuum, the packaging materials must possess high barrier properties. Commonly used multi-layer composite films, typically made from materials like polyethylene, polyamide, and aluminum foil, effectively block the intrusion of oxygen, water vapor, and light, constructing a robust physical barrier for the nuts.
However, the vacuum state is not a permanent solution. During storage, logistics, and shelf display, the packaged products continuously face environmental challenges. Therefore, the industry defines their commercial lifecycle through strict "shelf life" testing. This duration is determined through comprehensive evaluation by monitoring key indicators of the nuts, such as acid value and peroxide value, under simulated actual storage conditions. It serves as the scientific basis for quality assurance.
Furthermore, to enhance protective effects or meet specific process requirements, some products are filled with inert gases like nitrogen after vacuum sealing. This not only provides physical protection but also acts as a cushion, preventing the brittle kernels from breaking due to compression during transportation.
From the production line to the hands of consumers, every bag of vacuum-packed nuts represents a precise battle against time and the environment, embodying the integration of modern food technology and meticulous craftsmanship.