Introduction

Hpp juice is gradually replacing traditional thermal processing as a new choice for healthy living.

Hpp meaning is high pressure pasteurization, this technology can effectively kill the microorganisms and enzymes in the juice without applying high temperature, so as to maximize the retention of the juice’s natural color, pure flavor and valuable nutrients, such as vitamins and antioxidants.

So, how to accurately control the pressure in the process of producing HPP juice to get this result?

How to control pressure in the process

Core Equipment

The most important part of HPP equipment is the high pressure vessel and booster pump. A high-pressure container can be compared to an iron can that can withstand great pressure, and our juice products are placed in it. The booster pump is the core equipment that raises the water pressure to several hundred MPa. In addition, the pipeline system and various valves are responsible for the transmission and control of the fluid, and the pressure gauge (including sensors and display meters) is our monitor the pressure throughout the process. Each part is indispensable.

Working Principle

In a closed container, pressure is applied to the 1 fluid, and this pressure will be evenly transmitted to every point in the fluid, including every corner of our juice package. The high pressure will cause the microbial cell membrane structure to change, or even rupture, so as to achieve the effect of inactivation, but the flavor and nutrients in the juice will not be affected, so the taste and nutritional value of the juice can be preserved to the greatest extent.

The process is physical, without any chemical additives.

Workflow

• Product loading: Put the pre-packaged juice product into the high pressure container of the high pressure processing equipment.
• Sealing and water injection: After the container is sealed, the equipment will inject pure water as the pressure transmission medium.
• Boost process : The booster pump starts to work and gradually increases the water pressure in the container to the set value. At this stage, high-precision pressure sensors and pressure meters monitor and display the pressure changes in the container in real time. The process usually sets a pressurization rate and ensures that the pressure curve rises smoothly. Any unusual fluctuations could mean potential problems.
• Pressure holding: When the pressure reaches the preset value, the system will maintain the pressure for a period of time (usually 2-5 minutes). During the pressure holding period, the pressure meter can ensure that the pressure is always stable within the target range, and deviations of several MPa need to be vigilant.
• Pressure relief: after the end of the pressure, the system will slowly release the pressure in the container. The pressure relief process also needs to be monitored, and too fast pressure relief may cause impact on product packaging and even equipment.
• Product removal: After the pressure is completely released, open the container and take out the processed juice product.

Common Problems and Faults in Production Process and Their Solutions

Pressure Cannot Reach Set Value

• Phenomenon: The pressure gauge shows that the pressure rises slowly, or stagnates at a certain value and does not reach the target pressure.
• Possible causes: high-pressure pump failure, seal leakage (such as high-pressure vessel door or pipeline sealing ring), insufficient pressure transmission medium.
• Solution: First check the working status of the high-pressure pump and listen to whether there is abnormal sound. Then carefully check all sealing points to see if there is water damage. Finally, check the level of the pressure transfer medium tank. If you suspect a sealing problem, you can try to replace the sealing ring.

Pressure Is Unstable And Fluctuates Too Much.

• Phenomenon: The pressure gauge reading fluctuates continuously during the pressure holding phase and exceeds the allowable range.
• Possible causes: pressure sensor failure, control valve jamming, unstable output of high-pressure pump, incomplete discharge of air in the container.
• Solution: First calibrate or replace the pressure sensor. Check whether the control valve can operate smoothly. If the problem is suspected to be the pump, the pump needs to be maintained. In addition, sometimes the residual air in the container will also cause pressure instability, and it is necessary to ensure that the pressure-transmitting medium is fully emptied of air before each pressurization.

pressure relief too slow or too fast

• Phenomenon: When the pressure is released, the pressure meter reading drops at an abnormal speed.
• Possible causes: the pressure relief valve is blocked or malfunctioning.
• Solution: clean or replace the pressure relief valve.

pressure gauge reading abnormal.

• Phenomenon: The value displayed by the pressure instrument does not match the actual situation (it can be found by cross-verification or comparison with the standby instrument).
• Possible causes: the instrument itself is damaged, the sensor signal line is loose or interfered.
• Solution: Check the instrument wiring and try to recalibrate. If the instrument is confirmed to be damaged, replace it immediately.

In addition to the daily maintenance of the equipment, the most important thing is to rely on accurate interpretation and rapid response to the pressure meter data. Therefore, it is necessary to choose a certified pressure gauge, and regular calibration is also essential to ensure the accuracy of its readings.

high pressure certified

FDA and USDA: In the United States, the Food and Drug Administration (FDA) and the United States Department of Agriculture (USDA) have strict regulations on food processing, and HPP equipment and processes must meet their specifications.

HACCP system: Hazard Analysis and Critical Control Point (HACCP) system is an important tool for food safety management. HPP production lines must establish and effectively operate HACCP system to ensure that critical control points (such as pressure and holding time) are effectively monitored.

Application of high pressure equipment in other fields

Although this article mainly discusses the application of high-pressure pasteurization in juice production, high-pressure technology and related equipment do not stop there, and also show great potential in other fields.

Food processing: In addition to fruit juice, high pressure technologie is also widely used in meat, seafood, dairy products and ready-to-eat food sterilization, preservation.

Materials science: cold isostatic pressing equipment can be used to manufacture high-pressure environment for the synthesis of new materials, change the crystal structure of materials or ultra-high pressure molding, etc., in aerospace, automobile manufacturing and other fields have important applications.

Pharmaceuticals and Biotechnology  In the production and sterilization of temperature-sensitive drugs, vaccines or biologically active substances, high-pressure technology provides a 1 gentle and efficient method.

Summary

High-pressure pasteurization technology is a major breakthrough in the modern juice industry, and precise pressure control is the cornerstone of this technology. From the selection of core equipment, the understanding of working mechanism, to the real-time monitoring of pressure instruments in operation, to the investigation and solution of common faults, every step is inseparable from the fine management of pressure.