What Is The Winterization Process?
Winterization is a method of crystalline separation, a process in which oils and fats are separated by cooling them so that crystals such as glycerides, which have a higher freezing point, can precipitate out.
Winterization is also a specific form of dry fractionation, a refining process that follows after degumming, deacidification, decolorization, and deodorization processes. With precise control of the cooling rate, the completely melted liquid oil is stirred at low speed, and gradually cooling to 0-6°C for approximately 24 hours, during which will produce larger crystals of solid stearin, which can be separated and precipitated using filtration units.
For example, cottonseed oil needs to be winterized when preparing salad oil, fish oil needs to be winterized after refining to remove the stearin, paint oil shall be winterized to keep the paint film tough at low temperatures, edible oil is winterized to maintain transparency, and fluidity in the refrigerator, and cod liver oil shall be winterized to maintain clarity in cold weather.
The winterized fish oil is characterized by a freezing test and shall not cloudy after 5.5 hours at 0°C.
For specific oil winterization of your certain process requirements, welcome to discuss with us; we can provide customized solutions to your production process needs.
What is Winterized Fish Oil And What Are Advantages Over Regular Fish Oil?
Fish oil refined through a crystallization and filtration processes under freezing conditions is called winterized fish oil.
It remains clarified at temperatures above winterization and does not become cloudy and solidified.
Different winterized fish oils can be produced by sequential treatment of incubation and filtering at increasingly decreased temperatures and controlling the temperature required for different freeze filtration.
The lower the freezing point, the higher the unsaturated fatty acid content and the purer the quality of the winterized fish oil compared to normal refined fish oils.
Winterized fish oil is easier to use at lower temperatures, has a better smell and color, is purier, and has more stable indicators.
Why Fish Oil Needs To Go Through Winterization Process?
Fish oil is the fat of fish, which is the collective name for all the fats in fish, including body oil, brain oil and liver oil, whose main components are triglycerides, VA and VD, glycerol ethers, steroids and lipids, etc.
Fish oil, especially natural deep-sea fish oil, is rich in Omega-3 polyunsaturated fatty acids ( PUFA), in which eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are common functional nutrients and play an irreplaceable role in ensuring normal growth and development of animals, anti-inflammatory and disease prevention.
The fatty acid composition of fish oil varies considerably depending on the type of fish and the physical shape under different conditions of temperature due to the different saturated fatty acid content or the distribution of fatty acids in the glycerolipids.
At present, edible fish oil has strict freezing test requirements and must be winterized, which not only reduce the freezing point of fish oil, but also change the fatty acid composition, especially it can increase the EPA/DHA content, further improve the application value and economic value of fish oil.
When crude fish oil is obtained during the production of fishmeal. It contains a high acid value, impurities, and a high moisture content, which cannot be used directly for feeding. Because it is prone to disease and must be refined and winterized in order to obtain high-quality purified fish oil Omega-3 EPA/DHA PUFA for direct use in aquaculture and as nutritional supplements.
In line with the standard process of fish oil processing and the easy oxidation of fish oil, every production step from the crude fish oil shall be protected by nitrogen sealing, and the fish oil is transported in sealed pipes throughout the production process, with the right amount of antioxidants added to the finished fish oil to ensure the stable quality.
Fish oil can be divided into deep sea fish oil and fresh water fish oil according to the source of the catch, and the more common are anchovy oil, sardine oil, cod oil, tuna oil, squid oil and salmon oil according to fish species.
Natural marine fish oil contains up to 15%-35% EPA/DHA PUFA and is mainly used in healthcare products and high-end feed production. Freshwater fish oil, on the other hand, has a very low EPA/DHA content of only 2%-5% and is mainly used in low-end feed and chemical industries. Therefore, refined and purified natural deep-sea fish oil has a very high nutritional value and market value.
How to Tell if It is Crude Oil Or Refined Fish Oil?
The standard for judging the quality of fish oil should be based on the inspection and test results. Apart from the usual indicators such as odor, acidity, peroxide value, and water content, which can be separated through the refining and concentration processes, the level of EPA/DHA content is a hard indicator of the quality.
Refined fish oil shall have an acid value of less than 1, a peroxide value of less than 6, a relatively pure fishy flavor, a lighter color after refining compared to similar crude fish oil. It is golden yellow to reddish brown, with moisture and impurities all controlled at less than 0.3%.
High-quality refined fish oil must be protected by the addition of special antioxidants or nitrogen-filled gas, which substantially improves the oxidative stability compared to crude fish oil, ensuring the stability and safety of refined fish oils.
So high-quality refined fish oils have a typical shelf life of 2 years when they are completely isolated from oxygen and the production process essentially de-oxygenates.
The benefits of refined fish oil is fundamentally on the concentration of Omega-3 PUFA fractions. Deep-sea fish are rich in DHA/EPA PUFA through the diet chain and environmental factors, and the effects of different regions, seasons, climates, species, and food chains can result in different levels of EPA/DHA.
Naturally rich EPA/DHA fish oil has an irreplaceable effect on the normal growth and development of animals. EPA enhances the development of the gonads and improves reproduction. EPA/DHA improves resistance to coccidiosis and reduces the inflammatory response. It also improves the immunity of the animal, increases the survival rate of the young, and gives the animal a smoother, oilier coat.
Fish oil DHA/EPA helps to improve human physiological health, it has the ability to regulate blood lipids, and prevent cerebral thrombosis and strokes. DHA/ARA is used as an additive to milk powder to help infants improve their vision development. It also helps the body to absorb vitamins, minerals, and proteins, prevents Alzheimer’s disease, nourishes the brain, and improves memory, prevents arthritis, gout, asthma, relieves swelling and pain caused by arthritis, etc.
Fish Oil Winterization Fractionation Crystallization And Crystal Cultivation Reaction Tank
As the core equipment component of the winterization fractionation system, the crystallization and crystal cultivation reacting tank includes a nitrogen entry port, connected to a nitrogen displacement coil inside the reaction tank, a control assembly, set at the upper end of the reaction tank, and an output assembly including a gas outlet set at the upper end of the reaction tank. The gas outlet is connected to a breather valve to remove the displaced gas.
The structure of the crystallization tank is specially designed to solve the problem of residual volatile substances escaping after deodorization due to the intermittent or uninterrupted passage of nitrogen during the winterization and fractionation process, also it protects the fish oil from oxidation and improve the fish oil quality level.
It solves the problem of residual volatiles that cannot escape during the change from hot to cold and adhere to the oil interface, which will be seriously affecting the flavor and texture of the fish oil.
Engineering Case Study:
An Automatic Production Line Of Fish Oil Winterization Process With Quadratic Slow Cooling And Filtration Equipment
- Production Line Description: Intermittent winterization and fractionation processing of daily 10 tons of refined sardine oil by sequential treatment of incubation and filtering at an increasingly decreased temperature, aiming to increase the concentration of polyunsaturated fatty acids EPA/DHA content as per customer requirements.
- Design Philosophy: The process production line is specially designed on the principle of standard production, simplified process, energy saving and low emission, safety operation, and humanized production, aiming at reaching requirements on the refinement of sardine fish oil.
- Service and Supply Range：
- Provide process equipment design and electrical automation system design of fish oil winterization fractionation production line to meet customer requirements.
- Provide a complete set of process and electrical equipment for the fish oil winterization production line, excluding the equipment owned, self-made, or extra purchased by the user.
- Support to complete the installation and commissioning of related process equipment, piping, and power distribution, carry out production training to user staff.
- Installation materials include flanges, elbows, valves, pipes, and auxiliary steel materials for installation in the workshop.
- Stainless steel equipment appearance shall be with fine polishing treatment, the insulation appearance shall be an exterior tidy and clean and beautiful outline.
Process Step Of Fish Oil Winterization?
The winterization process for sardine fish oil ester follows a similar methodology to the winterization process for regular fish oil.
Winterization is a crucial step in refining fish oil to remove unwanted impurities and improve its overall quality.
Let’s explore the winterization process for sardine fish oil ester in more detail:
- When preparing for the fish oil dry fractionation and purification process, check the crude oil storage tank and start the pump to feed into the heat exchanger with precise metering through a mass flow meter, the refined crude oil shall be preheated to 40-50℃ with 2bar saturated steam, then the oil temperature will be precisely controlled by steam regulating valve opening degree.
- The crude nonwinterized oil enters into the first crystallization tank unit and starts the crystallization control program which is preset according to oil quality when the tank is filled full with oil. It follows a preset sequence from decreased temperature, crystallizing, incubation, and cooling to filtering temperature. Each crystallizer unit is equipped with self circulation cooling water pump to prevent the overcooling phenomenon.
- The automatic control system controls the temperature of circulation water and guarantees the regular slow decreasing of temperature in orderly steps, and precipitated stearin is with minimum liquid oil with smooth steps and easy filtering.
- The cooling decreased temperature, frequency, and the change in agitator speed throughout the incubation process can be automatically adjusted to optimize depending on the oil quality and the stage of crystallization. Each level of oil is pressed down in the crystallization process and moves in the tangent.
- In this way the oil in the crystallization tank is circulating in an even and flowing sequentially from top to bottom, forming a swirling and creating a vortex-like flow with no dead spots.
- Each crystallizing tank has a specialized capacity of 10 tons and can be filled in turn. The crystallizing process can be automatically started after each tank is filled respectively.
- The process of secondary crystallization and filtration is adopted, with four crystallization tanks for each stage of the process. The initial filtration temperature is set at 12℃, while the most applicable temperature shall be according to the production practice.
- When the fish oil enters into the fourth tank, the oil in the first tank with initially filled oil can be filtered. Open the bottom oil draining valve and start the variable frequency screw pump, pump the crystallized oil into the membrane filter press for the filtering process. Pump the liquid oil into the oil tank for storage. Melt the stearin with a heating coil and pump it into another tank for storage.
- When the oil inlet pressure of the filter press rises to a certain range, the filter stops the oil feeding and presses the filter in sequence, and automatically unloads the pan and closes to proceed to the next filtration process.
- The filtered liquid fish oil from the first section contains a small amount of stearin, to achieve the clarification and no turbidity of fish oil in 5.5 hours at 0℃, further cooling and crystallization filtration shall be carried out to remove the stearin at a lower melting point.
- The liquid oil is pumped into another four crystallizing tank units, the crystallizing process control will start when the tank is filled full of oil, and the program process is preset according to the oil quality. The crystallization process follows a preset sequence of slow cooling – crystallization -cultivation – and cooling filtration temperature. Each crystallizer is equipped with self circulation cooling water pump to prevent the over cooling phenomenon. The automatic control system controls the temperature of circulation water and guarantees the regular slow decreasing of temperature in orderly steps, and precipitated stearin is with minimum liquid oil with smooth steps and easy filtering.
- The complete crystallization process can be automatically adjusted to the preset specific cooling decreased temperature and frequency, blending speed, and incubation time according to the oil quality variety and stages. Each layer of oil is pressed down in the crystallization process, and moves toward a tangent line, thus all oil in the tank will be circulating and flowing sequentially from top to bottom evenly, forming an eddy state of complete mobility without any dead corners.
- The second section of crystallizing tanks also with a capacity of 10 tons and can be filled in turn. The crystallizing process can be started after each tank is filled. The second filtration temperature is preset at 2℃, while the most applicable temperature shall be according to the production practice.
- When the fish oil enters into the fourth tank, the oil in the first tank with initially filled oil can be filtered. Open the bottom oil draining valve and start the variable frequency screw pump, pump the crystallized oil into the membrane filter press for the filtering process. Pump the liquid oil into the oil tank for storage. The stearin can be melted with heating coil and pumped into the tank for storage.
- When the oil inlet pressure of the filter press risesto a certain range, the filter stops the oil feeding and presses the filter insequence and automatic unload the pan and close to proceed the next filtrationprocess.
Features Of The Winterization Process Design
The process design and equipment configuration are properly selected to meet the high-quality fish oil winterization and refining production requirements.
All the oil contact parts of the equipment in the process are made of stainless steel SS304 to ensure the stability of product quality.
Effective Control Strategies
The complete system realizes the implementation of computerized automated management, on metering, controlling, and sampling of flow, temperature, level, pressure, etc. throughout the process, as detailed below:
- This proposal designs a complete distributed control system(DCS) that can be a stand-alone, it combines a computer with programmable logic controllers (PLC) and various intelligent instruments to form a DCS (Distributed Control System) control system for the oil plant.
- The configured computer is collecting all kinds of original data on the production line and monitors the production process. It has the characteristics of centralized management and distributed control. In addition to the control function, the system also has the function of production management, which can display and assess the production data at any time. It meets the increasing production management requirements of modern factories and avoids the high risk associated with centralized control so that the reliability of the system is greatly improved.
- PLC programming according to process flow and production requirements to achieve winterization, separation, filtration, etc. Automatic control and monitoring of the production process.
- In the course of operation, if the equipment fails to stop, interlock control is carried out according to the process requirements, and the equipment in front of the direction of the incoming material of the faulty equipment is interlocked to stop to prevent the expansion of the fault. At the same time, an alarm signal is issued, and the computer multimedia function is used to provide picture prompts to the operator, indicating the fault point and the direction of the troubleshooting, etc. Enable the inspector to eliminate the fault as soon as possible and shorten the fault downtime.
- The workshop equipment control adopts a combination of automatic and manual, centralized and on-site control methods. Automatic can be completed by a computer-operated main command switch, Manual switches can be used for individual commissioning and troubleshooting. In case of an automatic failure, the manual switch can be used as a redundancy for the automatic to maintain production.
- Workshop control and monitoring content determine the monitoring point and configure the intelligent instruments according to the production process requirements. The control distribution diagram provided in this scheme is indicated in the process flow chart. Automatic control of feed flow, automatic detection of the liquid level of the main tank, temperature monitoring of key points, etc.
- Computers through communication with PLC and all kinds of intelligent instruments, can show the production equipment operation condition, the dynamic process, various process parameters, and the monitoring data of various control points to the operators. The operators can also control instructions on the computer, control the production process, adjust the state of oil refining, and Realize the production process through automatic real-time monitoring.
- The computer can automatically display, store and manage the original data collected on the production site, including the original records of output, power consumption, flow rate, temperature, pressure, frequency, and equipment alarming records.
Description Of Main Control And Monitoring:
- Feeding oil flow and output control: with the feedback of the flowmeter, the oil pump frequency conversion will control the feed flow.
- The main heating such as the preheating of the nonwinterized oil into the crystallization tank is controlled automatically by software and hardware to achieve precise temperature control.
- Level display of main water tanks, oil tanks, etc., with the ability to achieve automatic level control according to process needsThe monitoring or chain control of oil temperature and water temperature of key parts is realized by temperature sensors.Pressure monitoring of nitrogen and compressed air systems is achieved through pressure sensors.
- Advanced configuration of automatic instruments listed. The low-voltage electrical components mainly adopt brand products, France Schneider. The cable and wire are arranged by the bridge, which is convenient for operation and maintenance.
Conclusion
The fish oil winterization and refinement process can be optimized by adjusting the production process parameters on the equipment and control system, which will improve the professional skills and proficiency of the production operators, and reduce the production cycle time per unit of product and promote higher production efficiency, thus achieving an increase in the target capacity scale.
For any further technical or commercial disucssion on winterization process and equipment, please contact us soon.
Resources Links:
https://lipidlibrary.aocs.org/edible-oil-processing/dry-fractionation
