[China Packaging Reuters (Author: Labthink Technology Co., Ltd.) with the economic development and people's living standards, more and more pet into the family more, Correspondingly pet food industry The rapid development. Just like the ordinary food industry, pet food industry also has corresponding requirements for product safety and quality. Like other foods, pet foods have shelf life for a certain period of time. During the shelf life, pet foods need to be protected from deterioration or nutrient loss. There are many factors that affect the shelf life of pet foods, such as the use of additives (preservatives), packaging, storage conditions (temperature, light, etc.). This article aims to discuss the barrier properties of packaging materials for pet food shelf life and barrier detection methods.
According to AAFCO's standards, pet foods mainly contain proteins (above 18%) and fats, and supplementary nutrients include amino acids, minerals, crude fiber, crude ash, and vitamins. These nutrients can meet the growing needs of pets and keep the pet color bright, but it is also a good natural medium for microorganisms. Proteins in pet foods are broken down into organic amines, thiols and other substances under the influence of microorganisms. They have odor and cause food spoilage. Among them, fats are easily broken down by microorganisms to produce stimulants such as ketones and aldehydes that are pungent. . These decomposed low-molecular substances not only affect the sense of the pet food, but also have lost the nutritional value of the original substances such as protein and fat. Therefore, the activity of microorganisms should be suppressed as much as possible both in the production process and on the shelves.
As we all know, the breeding of microorganisms requires a certain environment. The three most important factors are ambient temperature, oxygen and moisture. Oxygen is the main cause of rancidity. The lower the oxygen content, the less likely the rancidity is, and the moisture can provide microorganisms with an active environment to accelerate the hydrolysis of fat and shorten the shelf life of food. During the shelf life, the oxygen and moisture content of the package is more dependent on the integrity and barrier properties of the pet food package. The barrier properties of packaging materials are particularly critical for the shelf life of pet foods.
Effect of Barrier Properties of Packaging Materials on Pet Food Shelf Life
During the shelf life, oxygen and moisture in the complete pet food package are mainly derived from the oxygen and water vapor that penetrates through the package. Barrier property refers to the hindrance of the packaging material to the permeation of gas or liquid molecules through the material. Labthink chooses seven pet food packaging materials commonly used in the market: PET, PET+CPP, BOPP/CPP, BOPET/PE, OPP/PE/CPP, BOPET/VMPET/LDPE, and aluminum-plastic composite film, respectively. Over-rate and water vapor transmission rate were tested, analyzed and compared. The greater the oxygen transmission rate, the worse the oxygen barrier property of the material; the greater the water vapor transmission rate, the worse the moisture resistance of the material.
Oxygen permeability test:
The Labthink OX2/230 Oxygen Transmission Rate Test System was used for this measurement. The instrument uses the equal pressure test principle. During the test, the specimens were first equilibrated in a standard environment (23±2° C., 50% RH) for 48 h, and the round specimens were taken from the unfolded portions. The pre-treated sample is placed in the middle of the upper and lower chambers of the OX2/230 Oxygen Transmission Test System. At this time, the sample is divided into upper and lower chambers. The upper chamber is a flowing high-purity oxygen, and the lower chamber is a flowing high-purity nitrogen. During the test, the oxygen molecules pass through the sample and enter the lower chamber. The high-purity nitrogen gas is brought to the oxygen sensor and detected by the oxygen sensor. The oxygen gas concentration and the oxygen permeability of the sample are calculated. This test uses 23°C, 50% RH test conditions.
Moisture permeability test:
In addition to oxygen, the penetration of moisture in the air can also accelerate the deterioration of pet foods. This measurement uses Labthink blue light W3/030 water vapor transmission rate test system. The test instrument belongs to the weighing method test. Select the equalized flat sample as the oxygen barrier test. Place the sample in a moisture permeable cup equipped with the instrument. Place a proper amount of distilled water that has been distilled twice into the cup. Humidity difference. During the test, the humidity difference between the two sides of the sample is controlled by controlling the humidity in the test chamber. The water vapour permeability of the sample was calculated by the weight reduction of the moisture permeable cup during the test test. This test uses 38°C, 90% RH measurement conditions.
Analyzed and compared the test results of the barrier properties of the pet food packaging of the seven structures, it can be found that the pet food packaging of different materials, due to the different materials of the composite layer, there is a difference in oxygen barrier. Among the samples tested, aluminum-plastic composite films, BOPET/VMPET/LDPE, and PET/CPP composite films have low oxygen transmission rates, and their corresponding pet foods have a longer shelf life, which is closely related to the high barrier properties of packaging. Related.
The composite membrane improves the water vapor transmission rate of the pet packaging material. The PET bag has poor moisture resistance and is not conducive to the storage of pet food. The pet food of the package has a short shelf life.
to sum up:
In summary, the barrier properties of packaging materials are extremely critical to the shelf life of pet foods. Manufacturers should pay attention to the selection of packaging materials with high barrier properties of composite plastic flexible packaging, aluminum plastic composite materials or tinplate materials. The choice of material must not only consider its oxygen barrier and moisture resistance, but also consider the influence of the environment on the barrier properties of the material. For example, EVOH and PA materials are extremely sensitive to environmental humidity. At room temperature and low relative humidity, the moisture resistance of these two materials is good, but in a high humidity environment, the moisture resistance will be greatly reduced. Therefore, this material should not be selected as a packaging material.