Source: Link Testing Instruments Co.,Ltd.
What properties should be paid attention to when bagged convenience bread comes into the factory?
• The barrier properties of oxygen and water vapor in the environment-to verify the oxygen permeability and water vapor permeability tests to prevent the packaging materials from causing moldy and reduced brittleness due to large permeability and poor barrier properties.
• Rub resistance-For composite films containing aluminum (such as aluminum-plated film, aluminum foil, etc.), the oxygen transmission rate before and after rubbing is tested for comparison and verification. If the rub resistance is poor, creases are likely to occur. Pinholes and other phenomena cause the barrier properties of packaging materials to decrease.
(2) Physical and mechanical properties
• Thickness uniformity—verified by testing the packaging thickness. The uniformity of thickness is the basis for ensuring good packaging material performance.
• Puncture resistance-verified by the puncture resistance test to prevent the packaging material from being broken due to poor puncture resistance.
• Slippery property—verified by the friction coefficient test to prevent the packaging material from being difficult to unwind or slip due to the friction coefficient being too large or too small.
(3) Hygienic performance
• Residual organic solvents—verified by solvent residual tests. If the residual solvent is too much, the packaging film will have peculiar smell, and the residual solvent will easily migrate to the packaged instant noodles, which will cause peculiar smells in the instant noodles and affect the health of consumers.
What is the reason for the increase in acid value (peroxide value) in instant noodle cakes?
During the shelf life, the acid value (peroxide value) of some instant noodle cakes is relatively high, even exceeding the standard.
(1) Packaging materials
• Poor barrier properties-the oxygen permeation from the outside of the package is higher, especially in the high temperature and high humidity environment, the gas permeation of the packaging material will be higher, resulting in the noodles being exposed to a large amount of oxygen and causing the oxidation of oil.
• Poor rub resistance-If the packaging material has poor rub resistance, when it is rubbed or squeezed by external force, it is easy to form creases, pinholes and other problems, which will reduce the barrier properties of the packaging material.
(2) Finished product packaging process
• Poor airtightness-the packaging bag body or heat seal is prone to air leakage under a certain pressure or long-term storage, especially the sealing quality of the heat-sealed part is poor, such as the heat-sealing strength is too low or too high, the heat-sealing strength If it is not uniform, air leakage is more likely to occur.
• The quality of the raw oil used in the noodle cakes is poor-if the quality of the raw oil used for the production of the noodle cakes is poor or long-term, repeated use, it is easy to cause the high acid value of the raw oil itself, which will further cause the acid value of the noodle cake (peroxidation). Value) exceeding the standard.
——Pay attention to the monitoring of the main performance of the package, such as heat sealing strength, oxygen transmission, oxygen transmission after kneading, air transmission, and sealing performance (negative pressure method).
——Adjust the parameters of the heat sealer to improve the quality of the heat seal; select packaging materials with high barrier properties and resistance to rubbing or improve the quality of existing packaging materials.
Typical quality case:
——Test sample: Fried instant noodle plastic composite film packaging (the customer reported that after the product was stored for a period of time, the quality of the noodle cake was found to be significantly higher than the previous product when the quality of the noodle cake was tested).
—— Targeted testing items: oxygen permeability, airtightness (negative pressure method).
——Test results: The oxygen transmission rate of the packaging film is 1478.1532cm3/(m2•24h•0.1MPa), which is much higher than the average value of similar high-quality products on the market, with poor barrier properties; sealing performance (negative pressure method) test In the finished product packaging at -68KPa, air leakage occurs at the heat seal, and the sealing performance is slightly poor. Therefore, the poor barrier properties of the packaging are the main reason for the higher acid value.
What are the reasons for the micro pinholes and air leakage on the surface of the instant noodle packaging bag?
The surface of the instant noodle packaging bag has small pinholes that are not easily detectable, which causes the packaging to leak.
• Poor puncture resistance-the hardness of instant noodles is greater, especially the broken noodles, which are sharper. If the puncture resistance of the packaging bag is poor, when the instant noodles are squeezed or dropped during the transportation and sale of the instant noodles, It is easily pierced by the dough.
• Poor thickness uniformity-thickness uniformity is the basis for ensuring the uniformity of other properties of packaging materials. If the thickness of the packaging bag is uneven or low, it will cause its puncture resistance to decrease.
——Pay attention to the monitoring of the main properties of packaging such as puncture resistance, thickness, and sealing performance (negative pressure method).
——Appropriately increase the thickness of the packaging and choose packaging materials with good puncture resistance.
Typical quality case:
——Test sample: instant noodle packaging plastic composite film (customers report that small pinholes often appear on the surface of the packaging bag during the sales process of this product).
——Targeted testing items: thickness, puncture resistance.
——Test results: the thickness uniformity is poor, the thickness of the thicker part is 40μm, and the thickness of the thinner part is only 35μm; the puncture resistance value is generally low and the uniformity is poor, the force value is 7.21N, the force The smaller value is 6.09N. Therefore, the uneven thickness of the packaging bag, low puncture force and poor uniformity are important reasons for the above problems.
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