Different foods have different chemical compositions and physical and chemical properties, so different foods have different protection requirements for packaging. For example, cakes are rich in oil and soft, and there are certain requirements for the optimal water content, so at least the following requirements should be met: high oil resistance, high oxygen resistance (to prevent oil leakage and oil oxidation) and high moisture resistance (to prevent cakes from drying and hardening after losing water). For another example, the packaging of tea leaves should have high oxygen resistance (to prevent the effective components from being oxidized), high moisture resistance (the tea leaves are moldy and deteriorated due to moisture), high light resistance (the chlorophyll in tea leaves will change under the action of sunlight) and high aroma resistance (the molecular aroma components of tea leaves are easy to be emitted and the taste of tea is lost). In addition, tea is easy to absorb foreign odors. A considerable number of tea in the market are packed in transparent plastic bags such as PE and PP, which greatly wastes the effective components of tea and the quality of tea cannot be guaranteed. Contrary to the above-mentioned food, fruits and vegetables have the choice of breathing function after picking, that is, the packaging is required to have different breathability for different gases. For example, fried coffee beans will slowly release carbon dioxide after packaging, and cheese will also produce carbon dioxide after packaging, so their packaging should have high oxygen resistance and high carbon dioxide permeability. The packaging of fruits and vegetables often requires mildew prevention, because the small water droplets on the inner wall of the packaging bag will have a series of adverse biochemical effects on fruits and vegetables, leading to the easy browning and rot of fruits and vegetables. Different varieties of fruits and vegetables and the same kind of fruits and vegetables with different maturity have different requirements on the permeability and selectivity of packaging materials. Raw meat, processed meat food, beverages, snacks, baked goods, etc. There are also great differences in the protection requirements for packaging. For example, the coating of canned meat should be sulfur-resistant, the coating of canned fruit should be acid-resistant, the container of aerated beverage should be pressure-resistant, and the packaging container of alcohol should be alcohol-resistant to block the aroma. Therefore, packaging should be scientifically designed according to the different properties of food itself and the protection requirements of water.
Second, choose packaging materials with suitable protection function.
Traditional packaging materials are mainly glass bottles, metal cans, cartons and cartons. Modern food packaging materials mainly include plastic, paper and composite materials (plastic/plastic, plastic/paper, plastic/aluminum, foil/paper/plastic and other types of multilayer composite materials).
1, composite material composite material is a kind of flexible packaging material with the largest variety and the widest application. At present, there are more than 30 kinds of plastics used in food packaging, and there are hundreds of multilayer composite materials containing plastics. Composite materials generally use 2-6 layers, and can reach more than 10 layers for special needs. Scientific and rational use of plastic, paper or tissue machine, aluminum foil and other substrates can almost meet the packaging requirements of various foods.
2. Plastics There are as many as fifteen or six kinds of plastics used in food packaging in China, such as PE, PP, PS, PET, PA, PVDC, EVA, PVA, EVOH, PVC, ionic bond resin, etc. Among them, PVA, EVOH, PVDC, PET, PA, etc. It has high oxidation resistance, and PVDC, PP, PE and so on. Has high moisture resistance; Radiation resistance, such as PS aromatic nylon; Low temperature resistance, such as PE, EVA, POET, PA, etc. Good oil resistance and mechanical properties, such as ionic bond resin, PA, PET, etc. , that is, high temperature sterilization and low temperature resistance, such as PET, PA, etc. Various plastic monomers have different molecular structures, different polymerization degrees, different types and quantities of additives and different properties, even if the same plastic brand is different. Therefore, suitable plastics or the combination of plastics and other materials must be selected according to the requirements. Improper selection may lead to the decline of food quality and even the loss of edible value.
3. Modern packaging paper and cardboard mainly use various processed potatoes (cardboard), composite paper, laminated paper (cardboard) and so on. , such as polymer material processing paper, wax processing paper, oil processing paper, cellophane, parchment, aluminized paper, paper/aluminum foil composite paper, etc. In transportation packaging, corrugated cardboard is used most, and corrugated boxes and trays almost replace wooden boxes. Honeycomb carton is the latest high-strength cardboard container. In addition, it should be noted that the internal structure, performance and cost of aluminized paper, aluminized plastic, paper/aluminum foil laminate and plastic/aluminum foil laminate are all different, and should be properly selected according to different protection requirements and cost requirements.
Third, adopt advanced packaging technology and methods.
In order to prolong the shelf life of food, new packaging technologies are constantly developed, such as active packaging, anti-mildew packaging, moisture-proof packaging, anti-fog packaging, anti-static packaging, selective breathable packaging, non-slip packaging, cushioning packaging and so on. These new technologies are widely used in developed countries, but they have not been widely used in China, and some methods are still blank. The application of these advanced technologies can obviously improve the protective function of packaging.
Four, the choice of packaging machinery and equipment and food processing technology.
In order to meet the needs of food processing technology, a variety of new packaging equipment have been developed, such as vacuum packaging machine, vacuum inflatable packaging machine, thermal shrinkage packaging machine, blister packaging machine, body-fitted packaging machine, sheet thermoforming equipment, liquid filling machine, forming/filling/sealing packaging machine, aseptic packaging complete equipment and so on. According to the selected packaging materials and packaging technology, it is the guarantee of packaging success to choose or design packaging machinery that matches the food processing technology and production capacity.
Five, packaging decoration design and brand awareness of packaging design
Packaging and decoration design should conform to the hobbies and habits of consumers in exporting countries. Pattern design is most in harmony with content. The trademark should be in an obvious position, and the text description should meet the food requirements. The product description should be true. Trademarks should be catchy, easy to understand, easy to circulate, and can play a wide publicity role. The packaging design of brand-name goods should have brand awareness. Some products are easily replaced, which affects sales. For example, China's Lao Liu vinegar has a good reputation in Japan and Southeast Asia, but because consumers have doubts about the new packaging, the sales volume has been greatly reduced after changing the packaging. Therefore, a product should be scientifically packaged and cannot be easily changed.
There are packages everywhere in life. It is believed that with the development of science and technology, more high-quality packaging products will emerge. At the same time, it will become a trend and determine people's buying trend. This survey is only my first time to set foot in food packaging, which is not perfect and comprehensive, but at the same time, the existing problems are also worth noting, that is, we should constantly improve the role of packaging in food to make it have more complete functions. The above is the whole content of my thesis.