Packaging and freezing of frozen conditioned foods
I. Methods and forms of packaging
1. Vacuum bag packaging can deal with all kinds of stretch packaging
instead of filling the contents into small bags in molded plastic boxes. Another form of packaging is vacuum bag packaging, which is widely used in frozen foods. Its advantage is that for individual heavy food (such as pig feet or large balls, etc.), this kind of 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. Another way is to adopt 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, then sealed with the upper film on three sides for the first time, and then evacuated, followed by the continuous operation of the second sealing and cutting. In foreign countries, this kind of equipment is a highly efficient equipment system, which has been used in the mass production of hamburgers, Shaomai and other frozen prepared foods. The main body of the packaging material is soft, so nylon/pe with good formability and non extensibility is mostly used, and the upper film is made of polyester/pe composite material sensitive to the mark of photocell and suitable for printing
2. Carton packaging
apart from the flexible packaging based on plastic film, the use of carton packaging is increasing. In addition to maintaining the swelling appearance, this packaging form accelerates the filling speed, improves the production efficiency, has a good appearance effect, and is more easy to handle and convenient for conditioning. The carton packaging of frozen food is divided into two ways: upper loading and internal loading. The former is made of PE and PP plastic films pressed together with cardboard on the surface, stamped and cut by a small-scale packaging machine, and made by a box making machine. After the contents are filled from the top, the machine automatically seals them with a cap. The box cover and the box body are connected into one piece. When the machine separates them up and down, the contents enter from the side and then seal automatically. This method is often used
3. aluminum foil packaging
aluminum foil, as a packaging material, has the advantages of heat resistance, cold resistance, good barrier, etc., and can prevent food from absorbing external bad odor, dry food, weight reduction, etc. This material has good thermal conductivity and is suitable for being used as a container for thawing and reheating
4. Packaging materials for microwave ovens
with the popularity of microwave ovens, heatable plastic boxes are used for the packaging containers of frozen food suitable for microwave heating, which can be used in both microwave ovens and ovens. The pressure vessel developed by internationalpaper company of the United States is extruded with long fiber base paper and polyester. The paper thickness is 0.43mm ~ 0.69mm, and the coating thickness is 25 μ m ~ 38 μ M. generally, it can withstand the high temperature of 200 ℃ ~ 300 ℃. The packaging materials of frozen food heated by special microwave ovens in Japan are polyester/paper, polypropylene and heat-resistant polyester
second, one of the reasons for the inspection of foreign matters is its narrow frequency band inspection and weight management
during the packaging process, the products with insufficient weight, loose sealing, exposed holes and other poor packaging phenomena or mixed with foreign matters such as metal sheets are inspected by senses or special settings. The commonly used detector is metal and weight separator. Foreign matter detection equipment is very important in the quality management of mass production of frozen conditioned food. Using equipment to detect all foreign bodies is also a subject that is being studied intensively in the world at present. The weight sorter calculates the allowable range before packaging, and sets it to the automatic confirmation device. The setting must be correct and appropriate. The light weight sorter is selected out, sent through the conveyor belt, and the light weight is pulled out by the separation device, so as to form a continuous production
III. frozen
in the sensory quality of food, the texture (organizational structure and physical properties i.e. taste) and taste of food are most concerned by consumers. When designing the quality of frozen conditioned food, we must fully consider meeting the above requirements of consumers. The factors that make up the taste include protein, carbohydrate, fat, etc. and the composition of water. The state of these substances in food determines the physical properties of food. The denaturation of protein during freezing is the main reason for the decline of its taste and taste. The most effective way to minimize its negative effects is rapid and low-temperature freezing. For the frozen processing of rice products and starch products, because the main component of this kind of food is starch, when frozen at low temperature, the taste of food will decline due to the aging of starch. 0 ℃ ~ 4 ℃ is the most aging temperature environment. 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, enter the rapid freezing temperature, and complete the quick freezing process. If there is an appropriate amount of liquid in the rice, it will reach the quality of frozen. Rice with liquid nitrogen as refrigerant has good freezing quality
in recent years, many new types of freezing equipment for conditioned food have emerged at home and abroad, from the original box type quick freezer to various quick freezing equipment such as screw type, liquid nitrogen type, tunnel type, flat plate type, etc. For the production of quick-frozen instant food, the current quick-frozen method in the conveyor belt still accounts for a large proportion because of its small size, short time of quick-frozen and easy to realize 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 pursuit of freezing production efficiency, resulting in unqualified products. The freezing time of food must be determined according to its type and shape. Take the appropriate temperature from the surface and center of the product, and select the appropriate freezing conditions
statement: 1. Grasp the production capacity with one hand
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