Application of freeze-drying technology in food processing
Freeze-drying technology has a wide range of applications. As early as the beginning of the last century, scientists have been freeze-drying biological specimens and strains in laboratories. Later, some industrial pharmaceutical plants used lyophilization to produce antibiotics and vaccines. Serum and various biological drugs. By the 1960s, developed countries such as Europe, the United States and Japan began to use freeze-drying methods to produce food. The main varieties are :Freeze Dried Mushrooms,
The Dried Fungus Mushroom， Dried Mushrooms, garlic, vegetables, beef, seafood, coffee, etc. In the 1980s, the production of freeze-dried products was almost everything, such as a variety of beverages, spices, fast food, snack food, health food, aquatic products, meat and eggs, edible fungi, enzyme preparations, algae, etc., while the scale and output were also expanding. In China, freeze-drying technology has long been used in the pharmaceutical industry. Biologic drugs such as antibiotics and vaccines are produced by freeze-drying methods. In the mid-1980s, the Northeast began to use lyophilization to produce ginseng, deer antler, aquatic products, fruits and wood products. It was gradually extended to food production, but the scale and scope of application remained small.
From an empirical point of view, freeze-dried foods should be selected for those species that have the characteristics of local resources and can highlight the lyophilization characteristics. Such as biological products, including enzyme products, fungi, algae, vitamins, etc., all contain a lot of heat-sensitive ingredients, can only be produced by freeze-drying methods; some famous rare animals, native products, aquatic products, flowers and fruits, etc. Need to maintain the original features, the same color appearance, both ornamental value and food value, with the freeze-dried method of producing an ideal effect; some health food ingredients containing high value, easy to lose and deterioration and difficult to save, with freeze-dried The method can solve this problem satisfactorily; for some foods with special flavors such as onions, peppers, fruits, coffee, spices, spices and beverages, processing by freeze-drying can make its flavor more intense; those daily foods such as vegetables, fruits, Aquatic products, meat and eggs, etc. can be processed into various convenience foods and fast foods by freeze-drying method, which has the advantages of rapid rehydration, crisp taste, beautiful appearance, and convenient consumption, and will be increasingly favored by people.
Application Prospect of Vacuum Freeze Drying Technology in Aquatic Product Processing
China's traditional luxury seafood processing products, such as scallop sea cucumber shark's fin and dried rice, are almost all processed by dry methods. Studies have shown that the use of traditional natural or artificial hot air dry processing of the above sea products, water-soluble and heat-sensitive nutrients such as a certain loss, at the same time, the product is a serious reduction in volume, rehydration is more difficult, but also prone to surface crustaceans Cracking, fat oxidation, resulting in product surface discoloration and other quality defects, affect the uniformity of product quality and tolerance. If vacuum refrigeration technology is used instead of traditional methods to process marine products, it will effectively overcome the above-mentioned deficiencies. It can not only ensure the homogeneity of the finished product quality, but also improve its appearance and intrinsic quality, and increase economic efficiency.
Vacuum freeze-drying technology can significantly improve the quality and grade of products, but it is slow to promote in the aquatic product processing industry. The reason is that there are four major concerns for policy-makers and investors: First, there is a one-time investment in equipment, domestic ZDG-60 1.5 million yuan is needed, ZDG-100 needs 2 million yuan, and the cost of imported equipment is higher; Second, the processing cost of vacuum freeze-drying equipment is high; Third, the supply of raw materials for aquatic products (especially sea products) is not stable, and the annual production can not be carried out continuously. , Long off-season time; Fourth, worry about the market for products.
First look at equipment investment issues. Large-scale production of lyophilized foods cannot be achieved only by the freezing equipment of the lyophilizer itself, and the food must be pre-frozen with a separate freezing device or warehouse, and then directly transferred into a vacuum dryer for dehydration. China's aquatic products processing industry has experienced sluggish operations in recent years, and some enterprises are in semi-discontinued state. Most of these companies bring their own refrigeration equipment or refrigerators. Investors can fully use these ready-made plant equipment and only need to add vacuum drying corresponding to their production capacity. Equipment can produce vacuum freeze-dried foods, thereby greatly reducing disposable equipment investment.
From the perspective of processing costs, according to the information provided by the U.S. Department of Agriculture, processing fees for vacuum freeze-dried foods are more than twice that of frozen foods and canned foods, but their sales and storage costs are low. From the total cost of the entire processing and distribution process, vacuum lyophilized foods were 1.02 times that of canned foods and 1.28 times that of frozen foods. The three were almost the same. If the lyophilized products are more expensive raw materials such as aquatic products, marine products, and marine drugs, the proportion of raw material costs to the total cost will be very close. At this time, the advantages of high-quality, high-grade, high-priced products of freeze-dried foods will be shown.
The raw material production of aquatic products is not stable, and the output of varieties varies greatly each year, and the seasonality is strong. This is a major feature of aquatic products production. At present, the international market has high demand for high-grade and high-quality vacuum freeze-dried foods in terms of quantity and variety. Therefore, it is necessary to break the traditional single production and business model and engage in the production of serialized and diversified products. Freeze-dried food factories can choose other kinds of foods according to their geographical conditions, depending on the season, to ensure the continuity of production. This will not only facilitate the organization of production, improve the utilization of equipment and economic benefits, but also enrich the product variety of enterprises and enhance their ability to withstand market risks.
