Frozen food carton packaging put through thawing tests

By Ahmed ElAmin

- Last updated on GMT

Related tags Graphic packaging Food preservation Food

Freezing and thawing tests indicate that coated unbleached kraft
paperboard packaging for the food industry stands up better than
other products, Graphic Packaging claims.

Wrinkled or deformed packaging on frozen products might lead consumers to believe that the food product has been thawed at some point and then refrozen, compromising food safety. The company is attempting to boost its market share in the frozen foods industry by attempting to show that its coated unbleached kraft (CUK) carton packaging does not wrinkle or deform as much assolid bleached sulfate (SBS) paperboard under the stresses of changing temperature. The defects are often the result of condensation that occurs due to temperature changes during transport and in the retail freezer case. Moisture absorbed by paperboard can soften and buckle thecarton, Graphic Packaging stated in releasing the results of the tests. Graphic Packaging markets its CUK under the SUS brand name. The tests were conducted by the company itself, with no independent verification available. In the US, Graphic Packaging holds a 25 per cent market share of CUK used for frozen food. This includes a 85 per cent share of all frozen pizza products by weight and 60 per cent of all frozenbakery products. Graphic Packaging is also the number one supplier of CUK in the world. Graphic Packaging says its three-ply construction of SUS folding carton grades enables the product to achieve superior resistance to compression and bulging, with the added benefit of hidingcoating flakes in the interior ply so that the back of the board is blemish free. "SUS is hard-sized to provide good moisture resistance, and natural resins in pine fibers further aid in water resistance," the company stated. The company performed tests to measure resistance to carton deformation by the degree of buckling occurring in the top carton panel after the carton was exposed to a series of freeze and thawcycles similar to those experienced by the carton as it moves from the filling line through the distribution chain to the retail freezer case. The freeze and thaw cycling results in an increase in moisture levels by several per cent, along with an associated decline in carton stiffness and compression strength, and varying degrees of mainpanel buckling. In identical structural designs, cartons produced from SUS exhibited less peak-to-peak deformation than the same carton produced with recycled freezer grades, and also exhibited less welting thanSBS paperboard. The tests also found that its SUS: had less peak-to-peak deformation than SBS. cartons made from SUS retained 56 per cent of their compression strength, compared to a 47 per cent retention rate for cartons produced with a leading SBS grade when cartons were exposed to controlled freeze and thaw cycles; and SUS 14 pt cartons retained 72 per cent of their strength, as compared to 16 pt SBS cartons' 66 per cent retention under similar conditions; With new capacity coming out of Latin American competitors, Graphic Packaging International also tested short span compression strength between one of these players and its SUS product. The tests found SUS retained more than 75 per cent of its short span compression strength after freeze/thaw cycles, while the Latin American competitor's product averaged around 60 per centretention. The freeze and thaw tests consisted of five, one-day cycles with 23 hours at 0F and one hour at 39F. Freeze-Thaw cycling consisted of five cycles with 12 hour at 0F degrees, followed by one hour at37F. External links to companies or organisations mentioned in this story: Graphics Packaging

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