Vacuum bag, aluminum foil bag packaging and freezing method

1、 Method and form of aluminum foil packaging and vacuum packaging

1. Vacuum bag packaging method

Vacuum bag packaging is another form that replaces filling the contents into the small bag packaging of the forming box, which is widely used in frozen food. Its advantage is that for individual heavy food (such as pig's hoof or big balls), this tight packaging will give consumers a certain sense of value. Vacuum automatic packaging equipment is easy to operate, with good appearance effect and convenient conditioning. The other way is to use fully automated new equipment, which respectively packs the upper film and the lower film. The filled contents are first placed on the machine with the lower film, and then sealed with the upper film on three sides for the first time, and then vacuumed, followed by the second sealing and cutting operation. In foreign countries, this kind of equipment is a highly efficient equipment system. It has been used in the large-scale production of hamburgers, roast wheat and other frozen processed foods. The main body of the packaging material is of soft type, most of which are made of nylon/PE with good formability and no extensibility, and the upper film is made of polyester/PE composite material which is sensitive to photocell marks and suitable for printing.

2. Carton packaging

In addition to flexible packaging based on plastic film, the use of carton packaging is increasing. In addition to maintaining the expansion appearance, this packaging form has the advantages of faster filling speed, higher production efficiency, good appearance effect, and more convenient handling and conditioning. Carton packaging of frozen food can be divided into upper loading and inner loading. The former is made of PE, PP plastic film and paperboard pressed together on the surface, punched and cut by a small packaging machine, boxed by a box making machine, and the contents filled from the top, and then automatically sealed with a cover. The box cover and the box body are integrated pieces. When the machine separates the top and bottom of the box, the contents enter from the side and then automatically seal. This method is used more often.

3. Aluminum foil packaging

As a packaging material, aluminum foil has the advantages of heat resistance, cold resistance and good barrier, which can prevent the food from absorbing external bad taste, smell, drying and weight reduction. This material has good thermal conductivity and is suitable for use as a container for reheating after thawing.

4. Packaging for microwave oven

With the popularity of microwave oven, the packaging containers of frozen food suitable for microwave oven heating have plastic boxes that can be heated. This material can be used in both microwave oven and oven. The pressure vessel developed by the International Paper Company of the United States is extruded with long-fiber base paper and polyester. The paper thickness is 0.43 mm~0.69 mm, and the coating thickness is 25 μ m~38 μ m. It can generally withstand the high temperature of 200 ℃~300 ℃. The packaging materials of frozen food heated by special microwave oven in Japan are polyester/paper, polypropylene and heat-resistant polyester.

2、 Inspection and weight management of foreign matters

In the process of packaging, the products shall be inspected by the senses or special settings for insufficient weight, lax sealing, exposed holes and other bad packaging phenomena or foreign matters such as metal chips. The commonly used detector is metal and weight sorter. Foreign matter detection equipment is very important in the quality management of mass production of frozen and processed foods. The use of equipment to detect all foreign matters is also a subject that is being studied intensively in the world at present. The weight sorter is to calculate the allowable range before packaging and set it in the automatic confirmation device. The setting must be correct and appropriate. The light weight sorter will be sorted out and sent through the conveyor belt, and the light weight sorter will be pulled out by the separation device, so as to form a continuous production.

3、 Freeze

The texture (organizational structure and physical properties, namely taste) and taste of food in the sensory quality of food are the above requirements of consumers. The composition of protein, carbohydrate, fat and water are the factors that constitute the taste. The state of these substances in the food determines the physical characteristics of the food. The denaturation of protein in the freezing process is the main reason for its taste and taste decline. The effective way to reduce its negative impact to low Z is fast and low temperature freezing. For the frozen processing of rice products and starch-based products, because the main ingredient of this kind of food is starch, the taste and taste of the food will decline due to the aging of starch when it is frozen at low temperature. 0 ℃~4 ℃ is the temperature environment where it is easy to age. Therefore, when this kind of food is frozen by the quick-freezer, it needs to quickly pass through the temperature zone prone to starch aging and enter the quick-freezing temperature to complete the quick-freezing process. If there is a proper amount of liquid in rice, it will reach the "ugly" quality when frozen. If liquid nitrogen is used as refrigerant for rice, the freezing quality is good. In recent years, many new types of frozen equipment for conditioned food have appeared at home and abroad, from the original box-type quick-freezing machine to various quick-freezing equipment such as spiral, liquid nitrogen, tunnel and flat plate. For the production of quick-frozen convenience food, the conveyor belt quick-frozen method still accounts for a large proportion in terms of its small size, short quick-frozen time, and easy to achieve rapid freezing, which improves product quality, improves production efficiency, saves energy, and reduces production costs. At present, many enterprises sometimes fail to reach the freezing temperature in order to pursue the freezing production efficiency, resulting in unqualified products. The freezing time of food packaged in food bags must be determined according to its type and shape. The appropriate temperature and freezing conditions shall be selected from the surface and center of the product.