Revolutionizing The Drying of High-Sugar Plant Extracts: A Low-Temperature Vacuum Drying Solution

Introduction

High Efficiency Vacuum Dryer for Lycopene Liquid

High Vacuum Dryer for Coffe Extract Liquid

The Problem with Spray Drying High-Sugar Plant Extracts

Spray drying operates as a continuous process in which a liquid feed is atomized into a hot drying chamber. The droplets' extensive surface area facilitates rapid water evaporation, yielding fine powders. Although spray drying is well-suited for numerous food and pharmaceutical materials, it faces challenges with plant extracts rich in high concentrations of sugars. Here’s an explanation of why:

1.Severe Wall-Sticking (Caking and Fouling):

Sugars exhibit low glass transition temperatures. In the high-heat, rapid-drying environment of a spray dryer (with inlet temperatures typically ranging from 150–180°C), the extract particles turn sticky and cling to the drying chamber walls. This phenomenon results in frequent operational interruptions, reduced production yields, and cumbersome cleaning processes.

2.Hygroscopicity and Re-Caking:

 Even when drying is successful, the resulting powder often rapidly absorbs moisture from the air, leading to re-caking and hardening during storage or packaging. This creates challenges in downstream processing—such as mixing, packaging, or sachet filling—compromising efficiency and reliability.

3.Loss of Active Ingredients:

4.High Energy Consumption:

Spray dryers rely on a continuous flow of hot air and frequently incorporate energy-intensive atomization systems, such as two-fluid nozzles or high-speed centrifugal disks. This makes the process costly, particularly when handling viscous or concentrated liquids.

Our Solution: High-Efficiency Vacuum Drying for Low-Temperature Granulation

To address these major challenges, we have developed a vacuum drying system that can directly convert concentrated plant extracts, especially those with high sugar content, into a solid, crumbly form. After drying, the material can be ground into instantly soluble granules with excellent flowability and prolonged shelf stability.

Key Process Parameters:

• Drying Temperature: Maintained at approximately 70°C, a low enough threshold to safeguard active compounds during processing.

• Vacuum Level: Operated at -0.099 MPa, utilizing deep vacuum conditions to enable gentle, low-temperature drying.

• Product Output: Yields brittle dry blocks or sheets that are easily crushable into powder or granules.

• Final Form: Results in non-sticky, hygroscopic-stable, and water-soluble granules with consistent physical properties.

Advantages of Vacuum Drying over Spray Drying

1. Low-Temperature Drying Preserves Bioactivity

Operating at around 70°C under a deep vacuum of -0.099 MPa, our vacuum drying system leverages the significant reduction in water’s boiling point under vacuum conditions. This allows moisture to evaporate at lower temperatures, creating a mild thermal environment that protects heat-sensitive constituents such as polysaccharides, glycosides, flavonoids, and volatile oils. As a result, the functional value of plant extracts remains intact throughout the process.

2. No Stickiness, No Wall Buildup

In contrast to spray drying—where sticky particles frequently cause fouling in the drying chamber—our vacuum dryer employs sufficiently low temperatures and a controlled, gradual drying rate to entirely prevent stickiness. As the extract undergoes slow, steady drying, it develops a porous, brittle structure that can be easily discharged from the chamber without any signs of clumping or caking.

3. Direct Processing of Thick Extracts

In spray drying, the extract typically needs to be diluted or adjusted to a specific viscosity range, which increases the water content and prolongs drying time. Our vacuum drying system, however, can directly process high-viscosity, concentrated extracts, eliminating the requirement for dilution and pre-treatment. This not only reduces energy consumption but also shortens processing time.

4. Easy Downstream Processing

Following vacuum drying, the material solidifies into brittle blocks that can be rapidly milled into consistent granules. These granules exhibit excellent flowability and non-hygroscopic properties, dissolving instantaneously in water. This makes them particularly suitable for applications in instant herbal beverages, pharmaceutical sachets, and nutraceutical formulations.

5. Energy Efficient

By eliminating the need for high-temperature hot air or atomization, the process significantly reduces overall energy consumption. Furthermore, since concentrated liquids are processed directly without dilution, the energy required to evaporate excess water is minimized. The result is a more cost-effective and environmentally sustainable drying process.

Applications in Traditional Chinese Medicine and Beyond

• Gan Cao (Licorice root)

• Huang Qi (Astragalus)

• Mai Dong (Ophiopogon japonicus)

• Sheng Di Huang (Rehmannia)

• Preserve their medicinal efficacy

• Dissolve instantaneously

• Maintain stability during long-term storage

• Functional food ingredients

• Plant-based nutraceutical formulations

• Instant herbal tea blends

• Sweetened beverage powder production

• Drying of fermentation broths

Conclusion: A Smarter Way to Dry High-Sugar Extracts

Summary Introduction

Our high-efficiency vacuum drying system offers a cutting-edge solution for processing high-sugar plant extracts, a category traditionally plagued by challenges such as stickiness, thermal degradation, and poor powder stability during spray drying. By operating under low temperature and deep vacuum conditions, our technology ensures the preservation of bioactive compounds while producing non-hygroscopic, instantly soluble granules. This process is especially effective for Traditional Chinese Medicine extracts, functional foods, and herbal nutraceuticals, providing superior product quality with lower energy consumption. With proven performance and scalability, our vacuum dryer sets a new standard for gentle, efficient, and clean drying of natural extracts.