Caramel treats is a kind of common pastry. It is made of flour, egg, sugar and nuts by deep frying. It is rich in nutrition and high in oil. It is easy to breed microorganisms and oxidize. In addition to strictly controlling the production process (such as adopting dynamic disinfection technology in its storage, transportation and shelf life) to prevent the total number of bacterial colony, Escherichia coli and other microorganisms from exceeding the standard, the level of packaging barrier performance is one of the key factors affecting the growth and reproduction of microorganisms. This is because most of the microorganisms that cause Caramel treats to become moldy are aerobic types, that is to say, the growth of these microorganisms need oxygen. By keeping Caramel treats in a low oxygen environment, it can effectively inhibit the reproduction of microorganisms and prevent Caramel treats from becoming moldy. In addition, this low oxygen environment can also avoid the oxidation and deterioration of oil in Caramel treats. Therefore, high oxygen barrier performance (i.e. oxygen resistance) is the basic requirement for Caramel treats packaging.

The test methods of oxygen permeability of soft plastic packaging materials are mainly divided into differential pressure method and isobaric method. This test uses the isobaric method to test the samples. The isobaric method is also called coulometric method. The standard used in this test is ASTM D3985-17 Standard Test Method for Oxygen Gas Transmission Rate through Plastic Film and Sheeting Using a Coulometric Sensor.

The sample tested in this test is a plastic composite film for packaging of a certain brand caramel treats.

The test equipment used in this paper is C230 Oxygen Transmission Rate Test System, which is independently developed and produced by Jinan Instruments Co., Ltd.

Isobaric method refers to a method in which the gas pressure on both sides of the sample is always consistent during the test. One side of the sample is filled with carrier gas, high-purity nitrogen, and the other side is test gas, high-purity oxygen. Under the effect of concentration difference, oxygen will permeate into the high-purity nitrogen side of the sample and be carried to the coulometric sensor by nitrogen for analysis, so as to obtain the oxygen transmission rate of the sample and other relevant parameters.

Test process

(1) After testing the thickness of the sample, place it in desiccators for 48 hours.

(2) Use a special sampler to cut three specimens from the sample.

(3) Apply a layer of vacuum grease around the test chamber of the instrument, clamp the sample on three test chambers of the instrument, remove the air bubbles between the sample and the test chamber, fix the chamber cover, and ensure the good sealing of the test chamber.

(4) Set the parameter information such as sample name, sample thickness, test temperature, test humidity, test mode, and click the “test” option to start the test. Turn on the air supply and adjust the air source pressure to make the humidity in the test chamber reach the set value.

(5) After the test, the instrument displays the test results of three specimens respectively. Purge the pipeline and shut down the instrument.

The oxygen transmission rate of the three specimens tested in this paper are 55.31cm³/(m²·d),58.07cm³/(m²·d) and 57.65cm³/(m²·d) respectively. The average value of the three specimens is 57.01cm³/(m²·d).

The permeability of oxygen has an important influence on the quality of Caramel treats within the shelf life. In this paper, C230 Oxygen Transmission Rate Test System is used to test the permeability of plastic composite film for packaging of Caramel treats. The test operation is simple, the instrument is intelligent and efficient. The test results show that the uniformity of the oxygen permeability of the sample is good. In addition to the oxygen permeability, the key indicators of Caramel treats packaging include heat sealing strength, sealing performance, grease resistance, tensile elongation and elastic modulus, solvent residue, total migration, etc.

Jinan Labthink Instruments Co., Ltd, is dedicated to providing customers with packaging testing solutions and helping the manufacturers to reach their goals of quality and safety assurance through improvement of packaging testing techniques and development of high-end packaging testing instruments. The newly introduced C series barrier testing systems adopting self-sensing technology revolutionarily improved the testing accuracy, efficiency and automation, realized the paradigm shift of packaging barrier testing instruments. For more information please visit www.labthink.com

Click here for more instruments for testing apckaging oxygen barrier properties.