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Puffed food packaging testing solutions and common questions

Jul 07,2024

Source: Link Testing Instruments Co.,Ltd.

When puffed food packaging materials enter the factory, what properties of the packaging materials should be focused on?

(1) Barrier properties

• Barrier properties to oxygen and water vapor in the environment - verified by oxygen permeability and water vapor permeability tests to prevent the packaging material from having a large gas permeability and poor barrier properties, which may cause puffed foods such as potato chips to have a reduced crispness and a "rancid" taste.

• Rub resistance - For composite films containing aluminum materials (such as materials containing aluminum-plated films, aluminum foils, etc.), oxygen permeability tests are performed before and after rubbing to compare and verify. If the rubbing resistance is poor, creases, pinholes, etc. are likely to appear, causing the barrier properties of the packaging material to decrease.

• Barrier properties to nitrogen in the package (nitrogen-filled packaging) - verified by nitrogen permeability tests to prevent the packaging material from having poor barrier properties to internal gases (i.e., large permeability), which may cause a decrease in the nitrogen content filled in the nitrogen-filled packaging.

(2) Physical and mechanical properties

• Thickness uniformity - verified by testing the packaging thickness. Thickness uniformity is the basis for ensuring good packaging performance.

• Smoothness - verified by the friction coefficient test to prevent the packaging materials used for puffed foods such as potato chips from being difficult to unwind or slipping due to excessive or low friction coefficients.

• Flexibility - verified by the tensile and elongation and elastic modulus and pendulum impact energy tests to prevent the packaging materials from breaking due to high brittleness.

(3) Hygienic properties

• Residual organic solvent - verified by the solvent residue test. If the residual solvent is too much, the packaging film will have an odor, and the residual solvent will easily migrate into the packaged puffed foods such as potato chips, causing the food to have an odor and affecting the health of consumers.

What are the product standards that can be referenced for flexible plastic packaging of puffed foods?

(1) GB/T 10004-2008 "Dry-type and extrusion-type composite films and bags for packaging": Applicable to plastic-plastic composite films and bags for food and non-food packaging, but not to packaging films and bags made of plastic materials and paper or aluminum foil, nor to wet-type composite films and bags made directly by co-extrusion composite technology.

(2) GB/T 21302-2007 "General Rules for Composite Films and Bags for Packaging": Applicable to composite films and bags for food and non-food packaging (except pharmaceutical packaging). This standard specifies the classification, requirements, test methods, etc. of composite films and bags for packaging made of different materials using different composite methods, but does not specify the index values ​​of each test item.

(3) GB/T 28118-2011 "Plastic and Aluminum Foil Composite Films and Bags for Food Packaging": Applicable to films and bags for food packaging made of plastic and aluminum foil with a total thickness of less than 0.25 mm and a use temperature below 70°C. (4) QB/T 1871-1993 "Biaxially oriented nylon (BOPA)/low-density polyethylene (LDPE) composite film and bag": Applicable to composite films and bags made of biaxially oriented nylon (BOPA) and low-density polyethylene (LDPE) resin or film through extrusion or dry lamination. Mainly used for vacuum, gas-filled, frozen, low-temperature sterilized packaging and general packaging films and bags.

(5) BB/T 0030-2004 "Aluminum-coated film for packaging": Applicable to aluminum-coated films produced by vacuum evaporation with biaxially oriented polyester (BOPET), biaxially oriented polypropylene (BOPP), cast polypropylene (CPP) plastic films as substrates, namely VMPET, VMBOPP (VMOPP), VMCPP.

(6) GB 9683-1988 "Hygienic Standard for Composite Food Packaging Bags": Applicable to food packaging bags made of paper, plastic film or aluminum foil with composite adhesive (polyurethane or modified polypropylene). Including cooking bags and ordinary composite bags.

What are the common packaging forms and materials for puffed foods?

1. Common packaging forms

(1) Plastic flexible packaging

• Ordinary plastic flexible packaging: that is, bulk packaging without any gas filling or vacuum treatment. Depending on the different barrier materials added to the packaging material, it can meet different shelf life requirements.

• Air-filled plastic flexible packaging: Air is filled into the finished packaging to prevent the puffed food from being crushed. Generally, materials with good toughness are selected to prevent the packaging bag from being easily broken.

• Nitrogen-filled packaging (plastic flexible packaging): Nitrogen is used as an inert environment to prevent fried puffed food from oxidizing and deteriorating. The corresponding packaging material should have a high barrier property to nitrogen and oxygen, and is mostly aluminum-plated composite film.

(2) Plastic barrel (box)

This type of packaging can prevent the puffed food from being crushed and is convenient to use, but it has poor sealing and a short shelf life.

(3) Paper barrel packaging

The paper barrel should have good stiffness to protect the puffed food inside from breaking. At the same time, some paper barrels contain high-barrier aluminum foil material on the inside, and the barrel mouth has a sealing cover film to achieve good barrier and sealing properties, and increase the shelf life of food.

2. Common packaging materials

• KOPP/VMOPP/LDPE: used for potato chip packaging, with good heat sealing, oxygen barrier, and light shielding, the shelf life can reach more than one year. If nitrogen filling is used, the shelf life can be longer.

• BOPP/VMPET/CPP (or PE), BOPP/PE/VMPET/PE/CPP co-extruded film, OPP/PET/Al/CPP: used for the packaging of puffed food, the form used is modified atmosphere packaging, with the advantages of airtightness, light shielding, oil resistance, etc.

• BOPP/VMCPP, PET/VMCPP: often used for the packaging of puffed foods such as potato chips, the cost is lower than the above two materials, but the shelf life of the contents is slightly shorter. The material can block oxygen, moisture, light, oil, fragrance, has a stiff appearance, bright colors, and low cost. Among them, BOPP, PET and VMCPP have good stiffness, BOPP has good printability and high gloss. VMCPP has good barrier properties, fragrance and moisture resistance, and CPP also has good oil resistance.

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