What Requirements Do Food Packaging Bags Place on Packaging Technology

An inconspicuous packaging bag on the market has its own story behind its production, and the production of packaging bags and packaging technology are among them. Today we explain the requirements that food packaging bags place on packaging technology.

I. The protective requirements of food must be understood

Different foods have different chemical compositions and physicochemical properties, so different foods have different protective requirements for food packaging bags. For example, cake is oily, soft, and has a certain optimal moisture content requirement, so at a minimum it should meet the following requirements: oil resistance and high oxygen barrier (to prevent oil seepage and oil oxidation), and high moisture barrier (to prevent the cake from losing moisture and becoming dry and hard). Another example: tea packaging should have high oxygen barrier (to prevent active ingredients from being oxidized), high moisture barrier (to prevent tea from absorbing moisture and becoming moldy and deteriorated), high light barrier (chlorophyll in tea changes under the action of sunlight), and high aroma barrier (the aroma components of tea molecules are very easily released, causing the tea flavor to be lost. In addition, tea is also very easy to absorb external odors). Moreover, quite a portion of tea on the current market is packaged in ordinary transparent plastic bags such as PE and PP, which greatly wastes the active ingredients of tea, and the quality of tea cannot be guaranteed. Contrary to the above foods, fruits and vegetables have respiration after picking, which requires packaging to have different permeability to different gases. For example, roasted coffee beans slowly release carbon dioxide after packaging, and cheese also produces carbon dioxide after packaging, so their packaging should have high oxygen barrier and high carbon dioxide permeability. The packaging of fruits and vegetables is often required to be mold-proof, because small droplets on the inner wall of the packaging bag have a series of adverse biochemical effects on fruits and vegetables, causing them to brown easily and rot easily. Different varieties of fruits and vegetables and the same fruits and vegetables at different maturity levels also have different requirements for the air permeability and selectivity of packaging materials. Fresh meat, processed meat foods, beverages, snacks, baked foods, etc. also have very different requirements for the protective properties of packaging. For example, the coating of meat cans should be sulfur-resistant, the coating of fruit cans should be acid-resistant, the containers of carbonated beverages should withstand a certain pressure, and the packaging containers of alcoholic beverages should be alcohol-resistant and aroma-barrier, etc. Therefore, packaging should be scientifically designed according to the different properties of the food itself and the different protective requirements.

II. Choose packaging materials with suitable protective functions

Traditional packaging materials are mainly glass bottles, metal cans, paper boxes, and cartons. Modern food packaging materials are mainly plastics, paper, and composite materials (plastic/plastic, plastic/paper, plastic/aluminum, foil/paper/plastic and other types of multi-layer composites), etc.

1. Composite materials Composite materials are the type of flexible packaging material with the most varieties and the widest application. At present, there are more than 30 kinds of plastics used in food packaging, and there are hundreds of multi-layer composite materials containing plastic. Composite materials generally use 2-6 layers, but special needs can reach 10 layers or even more. By scientifically and reasonably combining or laminating base materials such as plastic, paper or thin paperboard, and aluminum foil, almost all packaging requirements of different foods can be met.
2. Plastics There are also as many as fifteen or sixteen kinds of plastics used in food packaging in China, such as PE, PP, PS, PET, PA, PVDC, EVA, PVA, EVOH, PVC, ionomer resin, etc. Among them, those with high oxygen barrier include PVA, EVOH, PVDC, PET, PA, etc.; those with high moisture barrier include PVDC, PP, PE, etc.; radiation-resistant ones include PS, aromatic nylon, etc.; low-temperature resistant ones include PE, EVA, POET, PA, etc.; those with good oil resistance and mechanical properties include ionomer resin, PA, PET, etc.; and those resistant to both high-temperature sterilization and low temperature include PET, PA, etc. The monomer molecular structures of various plastics are different, the degree of polymerization is different, and the types and amounts of additives are different, so the properties are also different; even different grades of the same plastic may have different properties. Therefore, suitable plastics or combinations of plastics with other materials must be selected according to requirements; improper selection may cause food quality to decline or even lose edible value.
3. Paper and paperboard Modern packaging mainly uses various processed papers (paperboard), composite paper, laminated paper (paperboard), etc., such as polymer-material processed paper, wax processed paper, oil processed paper, cellophane, parchment paper, aluminized paper, paper/aluminum foil laminated paper, etc. In transport packaging, corrugated paperboard is used the most; corrugated boxes and pallets have almost largely replaced wooden boxes. Honeycomb cartons are the latest high-strength paperboard containers. In addition, one point should be noted: aluminized paper, aluminized plastic, paper/aluminum foil laminates, and plastic/aluminum foil laminates differ in internal structure, properties, cost, etc., and should be appropriately selected according to different protection requirements and cost requirements.

III. Adopt advanced packaging technology methods

In order to extend the shelf life of food, new packaging technologies that are continuously being developed are adopted, such as active packaging, mold-proof packaging, moisture-proof packaging, anti-fog packaging, anti-static packaging, selective permeability packaging, anti-slip packaging, cushioning packaging, etc. Developed countries widely apply these new technologies; China does not apply them commonly, and some methods are still blank. The application of these advanced technologies can significantly improve the protective function of packaging.

IV. Select packaging machinery and equipment that matches the food processing technology

In order to meet the needs of food processing technology, a variety of new packaging equipment has been developed, such as vacuum packaging machines, vacuum gas-flushing packaging machines, heat-shrink packaging machines, blister packaging machines, skin packaging machines, sheet thermoforming equipment, liquid filling machines, form/fill/seal packaging machines, aseptic packaging complete equipment, etc. According to the selected packaging materials and packaging process methods, selecting or designing packaging machinery that matches the food processing technology and production capacity is the guarantee of successful packaging.

V. Packaging decoration design and brand awareness in packaging design

Packaging decoration design should conform to the hobbies and habits of consumers and consumers in exporting countries. The pattern design should preferably be coordinated with the contents. The trademark should be in a prominent position, and the text description should meet food requirements. Product descriptions should be true. The trademark should be catchy, easy to understand, easy to spread, and able to play a broad publicity role. The packaging design of famous brand products should have brand awareness; some product packaging is changed easily, affecting sales. For example, China's Laoliutiao vinegar has a good reputation in Japan and Southeast Asia, but sales dropped greatly after the packaging was changed, because consumers were suspicious of the new packaging. Therefore, a product should be scientifically packaged and should not be changed easily.