SUNSAY freeze dryer: technology, applications, and cost

The sunsay freeze dryer technology applications and cost uses advanced food drying technology in a process carried out at subzero temperatures and under vacuum. After freezing, the product is placed in a vacuum so that its water changes directly from a solid to a vapor. This maintains the product’s structure, nutritional components, and color, improving its quality and value.

Introduction to the history of food freeze-drying

The history of food freeze-drying began in 1100 with the Incas of Peru, who took advantage of the high elevation of the Andes in South America (4,500 m). The cold air and low pressure at this elevation allowed them to freeze meat and several other foods.

Through the effects of solar radiation and low pressure, the foods tended to freeze-dry after they had frozen. The Incas of Peru used this natural freeze-drying method for centuries. The preserved foods were carried in “tâm bố,” a type of backpack used by marching armies.

Because these naturally freeze-dried foods produced good results, stores of fresh fruits and vegetables with enough capacity to feed 25,000–30,000 people began to be replaced by naturally freeze-dried supplies on this highland plateau in 1533. Later, in 1906, the French physicists Bordas and Darsonval invented equipment that condensed water vapor into ice by using snow mixed with acetone during drying.

Other French and American scientists continued refining the method for freeze-drying plasma, which was used successfully during the war between the United States and Japan in 1941. By 1942–1943, complete, high-capacity freeze-drying equipment was available for the pharmaceutical industry. Researchers then spent another 15–20 years developing applications of freeze-drying for the industrial production of different foods.

Today, freeze-dried food is produced on an industrial scale around the world, particularly for European and American markets. Freeze-dried food is produced for export because this processing method delivers the highest product quality.

Frozen products also retain almost all of their fresh characteristics, biological activity, and special properties, much like freeze-dried products. However, their subsequent storage and transportation must remain within an uninterrupted cold chain at subzero temperatures of -18 to -25°C. Therefore, if they are transported more than 300 km or stored for more than six months, the total cost of frozen products will be higher than that of freeze-dried products.

Freeze-dried products also offer many advantages for long-term storage at normal temperatures. Unlike frozen products, which must be kept continuously below -18°C, they are easier to transport and more convenient to use.

For 20 years, Italy has operated large, modern food freeze-drying plants that process agricultural and food products such as green beans, peas, cauliflower, tomatoes, cabbage, onions, garlic, oranges, tangerines, bananas, apples, pears, strawberries, meat soup, crab soup, and fish. Italian freeze-dried foods have entered many markets in Central and Northern Europe and the Americas.

Experts from the World Health Organization and the World Food Programme have paid close attention to freeze-dried food in food-aid programs for countries facing food shortages and areas affected by natural disasters (earthquakes, volcanic eruptions, droughts, and others). They concluded:

“Freeze-dried food offers many advantages over frozen products. It can be stored under normal conditions for many years, even in tropical climates, and its weight can be up to 12 times lower than that of the same type of frozen or canned food.”

Freeze-drying, which scientists call lyophilization, uses vacuum and freezing to remove water, a major cause of spoilage in food and pharmaceuticals. After freeze-drying, a product can be stored at room temperature for a long time without spoiling before the expiration date stated on its packaging. When the product is needed, water can be added to restore it to its original state.

Basic concept: sublimation

Vacuum freeze-drying is an advanced product-drying technique. First, the raw material is rapidly frozen at the triple-point temperature, causing the water in the product to become solid. Under vacuum, the ice then sublimates into vapor. The vapor is condensed into water and discharged, leaving the product dry.

The principle of sublimation can be clearly understood by examining the water phase diagram, specifically the water-vapor pressure curve.

The central principle of vacuum freeze-drying is to make water sublimate into vapor. In the diagram, the three lines OA, OB, and OC are called the liquefaction, vaporization, and sublimation curves. They show the relationship between water-vapor pressure and temperature in three phases: ice–water, water–water vapor, and ice–water vapor.

Point O is called the triple point. Its corresponding temperature is 0.01°C, and its vapor pressure is 6.11 mbar, 4.58 mmHg, or 611 Pa. At this temperature, water, ice, and water vapor can coexist in equilibrium. When the temperature or pressure changes, water may freeze, ice may melt, or a solid may change into a gas through sublimation.

Under a high vacuum, the principle of sublimation allows ice in the product to turn directly into vapor and escape without first melting, thereby drying the product.

This is why the process is called freeze-drying. In theory, sublimation only needs to take place at the triple-point temperature. In practice, the conditions are more demanding, and a vacuum of 0.5–1.5 mbar and a temperature of approximately -25°C are normally needed for the process to proceed smoothly.

Steps in the freeze-drying process

1. Fresh food is rapidly frozen at a very low temperature of -30 to -50°C and then placed in a vacuum chamber.

2. In the vacuum-drying environment, the ice crystals in the raw material sublimate without passing through the liquid phase. Approximately 90% of the moisture in the material is removed.

The product then moves to the secondary drying stage, where the remaining moisture is evaporated and the temperature is gradually increased, possibly to above 0°C. The moisture content of the material is reduced to approximately 1–4%.

3. The freeze-dried food is vacuum-packed to protect it from moisture and oxidation.

4. When the freeze-dried food is prepared for use and soaked in water, its flavor, nutritional content, structure, and shape return to their original state.

Advantages and disadvantages of freeze-drying

• The shape, color, nutritional value, aroma, composition, and flavor of the raw material change only slightly.
• The product is not contaminated, very little water remains (1–3%), bacterial levels are low, storage is easy, and transportation at room temperature is convenient.
• The product’s structure remains unchanged, it is easy to grind, and it can be easily restored to its original state.
• The equipment is expensive and difficult to operate. Operation below -60°C is difficult, and a high-performance vacuum pump is required.
• Packaging must indicate that the product is fragile. Because the product is highly hygroscopic, it must be sealed tightly.

Applications of freeze-drying

• Mangoes, pineapples, jackfruit, and other fruits; mushrooms, carrots, sweet corn, spinach, celery, peas, cabbage, shiitake mushrooms, red peppers, onions, leeks, wood ear mushrooms, cilantro, and asparagus.
• Sliced beef, sliced pork, chicken, and duck.
• Young shrimp, squid, small fish, crab, and scallops.
• Tofu, miso soup, soy sauce powder, vinegar powder, tea powder, and coffee powder.
• Royal jelly, pollen powder, fish-bone extract, garlic essential oil, lingzhi oil, shiitake oil, yeast, and antibiotics.
• Strawberry powder, banana powder, pineapple powder, and kiwi powder.
• Microorganisms, including different types of bacteria; starter cultures; blood plasma for medical use; biological specimens; and antibiotics.

How is the SUNSAY freeze dryer designed and manufactured?

The machine is designed by drying-industry experts with many years of experience to ensure the highest machine performance.

• The machine is manufactured entirely from imported, first-grade 304 stainless steel. Every component that comes into contact with the material is made from high-quality SUS 304 stainless steel, providing the highest level of food hygiene and safety.
• The refrigeration equipment consists of high-quality components imported from Europe.
• The machine has a modular design that meets export standards.
• The SUNSAY freeze dryer is fabricated on a laser-cutting and CNC-bending production line using the latest technology. This standardizes the precision of every component and gives the dryer a highly refined appearance, enhancing the quality of the equipment’s presentation when customers use it.
• The electrical system is designed to be user-friendly and easy to operate. In particular, the premium line integrates drying programs for each type of product, helping customers standardize their production technology. This ensures consistent product quality without depending on the operator.
• The service life of a SUNSAY freeze dryer is more than 50 years.

Investment cost of a freeze dryer

SUNSAY currently offers three main freeze-dryer lines:

• Freeze dryers for startups, with capacities from 3 to 10 kg per batch.
• Freeze dryers for small production facilities, with capacities from 10 to 50 kg per batch.
• Industrial freeze dryers for manufacturing plants, with drying capacities from 50 kg to 1 metric ton of product.

With an investment starting at VND 150 million, users can obtain today’s most advanced drying technology.

How much does a freeze dryer cost?

The SUNSAY freeze dryer is researched and manufactured in Vietnam by engineers with many years of experience in the drying industry. SUNSAY’s mission is to increase the value of processing and preserving Vietnamese agricultural products after harvest and help address post-processing challenges in the fruit sector. SUNSAY freeze dryers meet quality and food hygiene and safety standards.

With its reasonable price, SUNSAY Vietnam believes that the SUNSAY freeze dryer is a worthwhile investment for long-term use and delivers optimal performance.

The SUNSAY freeze dryer provides a new solution that saves time, reduces users’ investment costs, and delivers high economic efficiency.

SUNSAY currently offers freeze dryers for many production scales: from a 5 kg startup scale to a medium scale of 200–300 kg and a large scale of 5 metric tons of fresh product. The machines provide fast drying, maintain attractive color, save electricity, and achieve high efficiency.

Contact for a quote and consultation

The SUNSAY freeze dryer is researched and designed in Vietnam by engineers with more than 15 years of experience. Its mission is to increase the value of processing and preserving Vietnamese agricultural products and help address post-processing challenges in Vietnam’s agricultural sector.

SUNSAY dryers provide a new solution that saves time, reduces investment costs, increases productivity, and delivers high economic efficiency. With reasonable pricing, SUNSAY Vietnam believes this equipment is a worthwhile long-term investment that delivers optimal performance.

For detailed advice and a quote, visit kynghexanh.com.vn or call +84 94 110 8888.

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