Freezing techniques include freezing concentrated juices, quick-frozen vegetables, quick-baked baked goods, quick-frozen technology, pre-made frozen foods, etc., and the application of the principle of glass transition in the processing and storage of frozen foods.
Genetically engineered food ingredients, especially those with special flavor and color. Further, the resulting new variety is combined with a cryopreservation system to prevent quality changes during the freezing process.
Refrigeration technology and equipment in the food processing industry, pre-treatment, pre-cooling and quick-freezing of raw materials belong to the cold processing of food, which has great influence on the final quality of food. This link is also an essential process for frozen food factories, cooling meat and chilling. The freezing process of meat and acid-free, quick-frozen vegetables. China's refrigeration technology is growing, and frozen food is also favored by consumers. A better understanding of the origin of food sensory traits from a material science perspective.
Progress and development prospects of cryopreservation equipment
Application of the principle of glass transition in the processing and storage of frozen foods
As early as 1948, Schmidt and Marles pointed out: "Low-molecular weight-like substances like glass are an important class of solidified asphalt, natural resins, hard candy, etc.." In the mid-1960s, the United Kingdom Scientists White and Cakebread first proposed the idea of food glass transition in candy manufacturing. They recognize the importance of glass state, glass transition temperature, and glass transition temperature relative to the storage temperature of many liquid foods and the extreme importance of water as a food glass plasticizer. In 1985, the Royal Society of Chemistry held a seminar on water activity in Cambridge. The water activity was discussed extensively and carefully as a measure of food storage stability [3]. More than 50 scientists from different countries participated. After the meeting, after four days of academic exchanges and contends, he questioned the various defects of the effect of water activity on the storage stability and living viability of food, and put forward the theory of “food polymer science”. Although the number of people attending the meeting was small, the meeting was a milestone in the establishment of the theory of food polymers.
Microwave continuous thawing of frozen food
With the improvement of refrigeration technology, the need for efficient thawing technology to speed up the thawing process and to avoid affecting the quality of the final product has become the focus of the development of new thawing technology. Heretofore, the thawing of frozen foods has a natural thawing method using flowing water and a heat source thawing method using high-temperature air and steam. The treatment of frozen foods by such methods has problems such as oxidation and bacterial growth when the temperature of the food is slow when the thawing temperature is reached. An appropriate solution to the above problem is to develop an "internal" thawing method that maintains a low temperature, and the microwave heating method is attractive in this respect.
Because of the low penetration of microwaves, it is necessary to illuminate the frozen food from the upper and lower directions in order to reach the thawing temperature. This direct-emitting structure easily damages the magnetron if the transmitter is placed on both sides of the conveyor belt.
Advanced application Packaging material
A Japanese company has recently developed a highly absorbent fiber for food packaging that is already being used as a food packaging material and has been approved by the Food and Drug Administration (FDA). The non-woven sheet made of this highly absorbent and highly hygroscopic fiber can absorb 50mL of water per gram, which is about 5 times higher than the original pulp sheet, and can withstand 150 ° C high temperature, even high pressure. It can also maintain its moisture. According to the test, the fiber is used as a meat packaging material, which has good safety performance and can absorb the blood and moisture of meat to keep it bright.
Use more advanced technology to measure the temperature of frozen foods
A new instrument that detects the temperature of frozen foods without contact. It is well known that frozen foods tend to deteriorate in quality due to improper temperature management. Usually, bacteria begin to proliferate at 8 ° C or slightly higher temperatures, so strict and correct temperature management is required. Unfortunately, the thermometers commonly used in freezer libraries are always affected by air flow such as opening of the door, automatic defrost, and new goods entering the warehouse. The measured temperature often changes and does not represent the correct temperature of the frozen food.
Applying other potential methods to processing cooled foods and package
NOVA, a manufacturer of petrochemicals and plastic products, recently announced the official launch of two new types of Surpass polyethylene resins for use in demanding frozen food packaging. These two product numbers, IFs542-R and IFs730-R, provide sufficient impact resistance for ice cream and other frozen foods at very low temperatures.
SURPASSIFs 542-R and IFs 730-R resins are used in frozen food containers and container lids, respectively, and are currently marketed in both sample and commercial form. In addition, these two new SURPASS resins will be added to the NOVA Food Packaging Performance Kit, which also includes DYLARKFG, foamed DYLARKFG, ZYLAREX and other SURPASS resins.
Bixel Plastics produces two platters to package frozen fast food. One is a crystalline vinegar tray that can be used in both furnaces, and the other is a polypropylene tray without barriers, which can only be used in microwave ovens.
The heating method used is one that is used in a microwave oven and the other in a conventional oven or microwave oven. In the latter case, the shallow tray used must be usable in both furnaces. Most of the fast foods are packaged in the above-mentioned platter. In order to meet the growing demand for frozen foods, the processors have adopted Mechanized shallow pan filling and sealing production line.
At 80-85 ° C, pasteurization solves the problem of bacterial growth due to changes in storage temperature or insufficient heating by the consumer.
Pasteurization can extend the shelf life of frozen foods by at least six weeks. The deoxidizer can reduce the oxygen in the package, resulting in an anaerobic environment. Maintaining this state prevents oxidation of multi-fat snacks. Pasteurization of packaging, vacuum packaging and fast food protects frozen foods from moisture and shelf life.