• Cooling India
  • Aug 15, 2016

Evolution Of Latest Technology In Individual Quick Freezing (IQF)

With India’s food production likely to double in the next decade, there is an opportunity for large investments in food and food processing technologies, skills and equipment, especially in areas of Canning, Dairy and Food Processing, Specialty Processing, Packaging, Frozen Food/ Refrigeration and Thermo Processing...

- Ritesh. J. Mistry


Individual Quick Freezing (IQF) technology used will be latest and indigenous. It is a freezing method of choice for seasonal products such as fruits and vegetables – and over the years it has further developed to cover a broader range of other product such as diced meat, shrimps, pasta and rice, dairy products and etc. IQF is a technology originally developed by Frigoscandia Equipment as a specific solution to block or cluster-freezing of small-sized products, to preserve quality and to give unparalleled convenience to end-users. Quick Freezing is the only process whereby, virtually all the properties of most of the parent food stuffs can preserved.

  India is the world's second largest producer of food next to China, and has the potential of being the biggest within the food and agricultural sector. With India's food production likely to double in the next decade, there is an opportunity for large investments in food and food processing technologies, skills and equipment, – especially in areas of Canning, Dairy and Food Processing, Specialty Processing, Packaging, Frozen Food/ Refrigeration and Thermo Processing.

  This system involves the use of a blast of cold air which, when directly on the food products, quickly freezes them. The vegetables are also frozen in air blast tunnel (chamber freeze) in which cold air at –40 degree C is rapidly moved around the product giving it a cryogenic shock and freezing it instantly. This type of freezing results in the product free rolling and not clotting into lumps.

The Evolution of IQF Technology

  IQF stands for Individual Quick Freezing – and is a technology used in the food processing industry. As the term suggests, it stands for the quick freezing of individual pieces of product, as opposed to bulk or block freezing.

  IQF technology has its roots back in the 1960s when the freezing tray freezer was introduced on the market. It was an immediate success as the prior freezing methods were block freezing of products (or even packaged products) which degraded the overall quality due to its long freezing time. Tray freezer performed well on ‘easy to freeze’ products like pea, corn or carrots. The transportation of the product was based on the fluidization principle. However, for rather delicate and light weight products like broccoli, raspberries, herbs, etc., the air speed needed to achieve transportation was too high and products would get destroyed or flown over the bed. Therefore, the flexibility of this type of freezer was limited. 

  In 1970s the engineers came up with a solution and introduced the transportation belt. With this innovation it was possible to transport the product at lower air speeds, as the belt was in charge of transporting the product. However, by introducing a belt in the freezer the number of moving parts increased which is a hazard for food safety. In addition, a belt-take-up mechanism was necessary to be introduced due to temperature variations.

  Since 1970s, stainless steel type of mesh-belt was used in IQF freezers. Many freezers today use the same type of technique even if belt configuration can vary. The disadvantage of this belt is that it cannot produce true fluidisation, as the holes in the mesh are too big. In addition, such belts would always leave belt marks on relatively fragile products such as strawberries. An efficient cleaning of such type of belt is difficult which is another important drawback.

  As a response to these challenges, in 1980s plastic belts were introduced in the IQF freezers, a technology which significantly improved the freezing results. The challenge for this type of belts is that only 64% of the surface of the belt has active fluidisation while the rest of 36% is a dead zone as the air flow is hindered by the connection pins.

Figure 1: Process flow diagram of IQF...

  The latest innovation in terms of beds used for IQF freezers is the perforated bed plate designed which is a successful replacement for the belts used before. Transportation of the product is based on a patented principal which consists of an asymmetric movement of the bedplate in the direction of transportation using static friction between the bedplate and the product to be frozen. In the case of the modern IQF freezer bed plate – almost 100% of the surface of the bed has active fluidization. The possibility of configuring the diameter and shape of the perforated holes contributes to the impressive freezing results while the cleaning of the beds can be made easy and fast outside the IQF freezer. This new technology of bedplates have marked an impressive technological progress in the IQF industry.

  Additionally, the Modern IQF tunnel is equipped with a Clean In Place system and a foam system for disinfection and cleaning between production.

  Cooked meat, as well as challenging products like raw or minced meat or sticky marinated meat, can be frozen by freezer with good separation using the features of the bed vibrator or pulsator. Despite any other technologies, the modern IQF tunnel freezer ensures more performance, at lower power consumption.

Manufacturing Process & Technology

  Oxidation (rancidity) can occur during freezer storage causing off flavours through exposure of frozen product to air. Using high quality plastic bags or containers designed for freezing can prevent rancid flavour development as well as protect against freezer burn which is a result of moisture loss. The process of freezing involves freezing the water in the cellular spaces of fruit tissue. As this water freezes, it expands forming ice crystals that rupture cell walls resulting in softer texture once fruit is thawed. To reduce cellular damage chill and freeze fruit quickly so that the ice crystals formed are smaller. Process flow of IQF & typical flow for ice cream manufacturing is given in figure 1 & 2.

Figure 2: A typical process flow for ice-cream manufacturing...

Technology

  The technology of IQF involves three sub sections:

1. Processing Equipment
2. Individual Quick Freezing Equipment
3. Auxiliary Equipment

  Processing equipment involves Pea Podder, cross collection conveyor for peas, waste collection conveyor, bucket elevator, Winnower, Fruit/Vegetable washer, Inspection Conveyor, Pea blancher, After cooler, dewatering conveyor, grain recovery system and potato dicer etc.

  Freezing equipment is with Polyethylene product belting. High efficiency SS coils, air foil fans. It consists of Conveyor System, Defrost system, refrigeration evaporator, freezer enclosure, Belt washer and dryer and electrical control panel, Caycore IQF soft, Dual Defrost Mechanism and refrigeration machine etc.

  Auxiliary Equipment consists of Boiler, Reverse Osmosis plant, Laboratory Equipment, Fire Fighting equipment, ETP, Electrical infrastructure and accessories etc.

Applications

• FRUITS AND BERRIES
• TROPICAL FRUITS
• VEGETABLES
• CHEESE
• PASTA & GRAIN

• FRUITS

  One of the most challenging aspects when freezing fruits, especially tropical fruits like banana and mango, is the separation and keeping their taste, smell and texture intact. Some products are extremely sticky due to their naturally high sugar content and they will easily stick together in lumps or blocks.

  The benefits of IQF tunnel freezer is that it is designed with up to five (5) freezing zones that control the circulating, bubbling and fixed bed fluidisation. This enables quick freezing of the surface of the products to avoid dehydration and lump formation. The aerodynamics and movement of the bedplates ensure that there will be no belt marks on the product surface, nor damage on the product corners.

• BERRIES 

  Delicate berries are sensitive to mechanical impact and must be handled with care, to avoid damage or marks. Some soft berries, like raspberries, are extremely sensitive in a frozen state, but quality equipment shows very good results due to the adjustable freezing zones. The optimal aerodynamics in each zone, and gentle bedplate movements of IQF freezing tunnel, separate the products with a minimum of crumbles and fines.

  Low dehydration and no lump formation also add to the natural appearance of the berries, preserving color, size and shape.

• TROPICAL FRUITS

  One of the most challenging aspects when freezing tropical fruits such as banana and mango is to achieve good separation and preserve their taste, smell and texture. Some products are extremely sticky due to their naturally high sugar content – and they will easily stick together in lumps or blocks.

  Depending on the ripeness of the product, the additional features of the pulsator, bed vibrator or the wave plate will effortlessly separate the products, creating a perfect output and keeping the fruits’ delicate natural colour and shape.

• VEGETABLES

  Frozen vegetables maintain their natural appearance, texture and colour when frozen in an IQF freezing tunnel. For some type of vegetables, the fluidisation inside equipment even enhances their appearance. This is possible with the optimal bedplate configuration and the easily controlled freezing process in the IQF freezer. Delicate and fragile vegetables like broccoli, spinach or asparagus require gentle handling in order not to get damaged. But even more solid vegetables like beans, mushroom, peas, brussels sprouts and carrots benefit from the unique airdynamics in the IQF freezer.

  The individual quick freezing tunnel developed by Octofrost has some additional features, like the pulsator, bed vibrator or the wave plate that will contribute to the product's separatation so that the fresh-frozen products will preserve their delicate natural colour and shape.

  Additionally, the low snow formation and dehydration level during the IQF freezing process in Freezer will increase the output of frozen products without spending additional resources on raw material, manpower or power consumption.

• MEAT & POULTRY

  Food safety is a top priority for customers in a modern food processing industry. With bacteria like listeria, salmonella and E. coli that can be found in meat and poultry, the mono-block design, rounded corners and no joints of the IQF freezing tunnel ensure that bacteria have nowhere to hide.

  The open access and exchangeable bedplates for easy efficient cleaning further boosts the level of food safety.

  Additionally, the Modern IQF tunnel is equipped with a Clean In Place system and a foam system for disinfection and cleaning between production.

• CHEESE

  The uniform and gentle fluidisation in IQF freezing tunnel ensures there is no damage on cheese corners and no formation of fines.

  With five days of production without defrosting and 100% separation you can rest assured of a natural appearance of your cheese, even on sticky products like shredded mozzarella.

  The minimum of fines gives a commercial high-quality IQF frozen product that can be sold at a premium price.

  Food safety is key for customers in a modern dairy processing industry. The mono-block design, rounded corners and no joints ensure that freezer meets the highest requirements on food safety. The open access and exchangeable bedplates for easy efficient cleaning further heighten the level of food safety control.

  The low snow formation and low dehydration level during the freezing process will increase the output of frozen products without spending any money on raw material, manpower or power consumption. 

• PASTA & GRAIN

  Freezing delicate and sensitive pasta is optimal in an IQF tunnel units. The benefits of individual quick freezer is that it is designed with up to five (5) freezing zones that control the circulating, bubbling and fixed bed fluidization. This enables quick freezing of the surface of the products to avoid dehydration and lump formation. The aerodynamics and movement of the bedplates ensure that there will be no belt marks on the product surface, nor damage on the product corners. With low dehydration and no lumps your pasta will keep its natural appearance in volume and shape, and will fill the bags better.

BENEFITS

• NATURAL APPEARANCE

  The unique fluidisation method of the IQF tunnel enhances the products’ natural colour and shape. Floating freely on the freezers powerful circulating or gently bubbling air currents, the products recapture the true beauty of nature.

HIGH VOLUME

  Products which are floating freely on a circulated fluidised bed, release inner tensions and retake their natural volume and shape. Bigger volume of equipment fills bags and boxes better. It is a win-win situation as the customers and consumers will enjoy the intact products with their natural volume maintained.

COLOUR

  The combination of optimal air distribution and minimal dehydration in the freezer preserves the natural colour of the frozen products. The surface of the product is protected by a transparent frozen coat which preserves the products’ appearance as well as prolongs their shelf life. These are just a few of the main advantages achieved by innovative IQF freezing tunnel.

NATURAL APPEARANCE

  Beautiful appearance sells. A product frozen in circulated fluidised airstream preserves its natural form. There are no damages to the product such as freezer feet or belt marks. The thin reglasing of the product protects the colour of the frozen product. All because modern IQF tunnel is designed to ensure reliable food safety and natural appearance.

• FOOD SAFETY

  Latest IQF freezer is designed as an easy accessible hermetic unit with rounded corners and sloping surfaces. The bedplates are removable for easy cleaning, minimising the risk of cross contamination between products. In combination with an effective Clean In Place (CIP) system, helps to maintain high food safety standards.

CLEANABILITY

  When designed individual quick freezing technology, we have to keep in mind two main features: Food safety and cleanability. Unit can be cleaned with impeccable results, even with limited available time. Easily removed and cleaned outside the freezer, the bedplates decrease downtime without compromising food safety.

EASY ACCESS

  Never before has a freezer been easier and faster to clean. In the modern IQF freezer developed has every surface on each detail is easily accessible thanks to the completely open design.

  The bedplates are cleaned outside the freezer and all other parts can be effortlessly accessed for thorough cleaning and bacteria control inspections.

MONOBLOCK DESIGN

  Made of non-hygroscopic material, the IQF freezer features a unique octagonal monoblock design. Designed as one ready to install unit, the freezer has rounded corners and even surfaces which slope towards the drain area.

IMPORTANCE OF FOOD SAFETY

  A Food Safe freezer proves its performance when it can be washed and disinfected in short time during peak season. Totally clean, free from bacteria’s, microbes or listeria that could circulate around when the fans are running full.

• HIGH YIELD

  Higher yield means more kilos of frozen products on invested raw material, man power and energy. A latest technology IQF freezer boosts up yield with at least 1.5–3%, and for many products the figure might be even higher.

  With the vast volumes of products which passes through the freezer every year, a higher yield is without doubt the most efficient way to increase the profit – from day one and for all the years to come.

DEHYDRATION

  The complex air flows and pressure ratios have been combined to reduce product dehydration and prevent snow formation in the freezer. Applied on all application areas, the snow formation is below 0.5%.

REDUCTION OF LUMP FORMATION AND FINES

  With the powerful and controlled circulated fluidisation in the IQF freezer, in combination with its unique bedplates, even sticky products are prevented from lumping together in blocks. Further in the freezing process, the bubbling fluidisation ensures a safe transportation of the product avoiding any damages and reducing the amount of fines.

IMPORTANCE OF HIGH YIELD

  Nothing has more importance to the return of investment than high yields. Each percent of increased yield means one percent of increased yearly incomes without spending money on raw material, man and electrical power.

• ENERGY EFFICIENCY

  The latest unit in IQF technology ensures lower energy consumption and waste for IQF production. The main reason is the compact octagon body with efficient aerodynamics throughout the freezer and especially the fluidising freezing zone. Compact body and less turbulence require less fan power consumption.

BEDPLATES INSTEAD OF CONVEYOR

  The worldwide patented use of OctoFrost bedplates instead of conveyor belt inside the freezer, not only facilitates cleaning and food safety but also allows better adjustment of fluidisation, which keeps the natural shape of the products and allows less fan speed. 

FREQUENCY INVERTER CONTROLLED MOTORS

  Fans and bed drive motors inside the latest individual quick freezing tunnel, are controlled with inverters. This allows lowest energy consumption. Modern motors specialised for running in cold environment are supplied from leading manufacturers.

TIME BETWEEN DEFROST

  PLC operated SRS system keeps the front of the coil clean during production and substantially prolongs the number of production hours between defrost/cleaning. This minimises downtime and water consumption for defrosting.

MINIMISING DEHYDRATION

  The unique design of the individual quick freezing tunnel prevents snow formation. All snow that builds up during production inside a freezer is considered a direct waste of energy.

EFFICIENT PLC OPERATION FOR DEFROST AND CLEANING

  PLC operated coil cleaning system controls the consumption of water needed to de-frost the coil – and eliminates the risk of wasting water.

IMPORTANCE OF ENERGY EFFICIENCY

  With frequency convertors on every energy efficient axial vane fan, the total energy savings are substantial. On top of this, setup requires less refrigeration to cool down the fans. A total energy saving is up to 20 to 30%. 


Reference -
Sun, Da-Wen (2001). Advances in food refrigeration. Leatherhead Food Research Association Publishing. p.318. (Cryogenic refrigeration)
http://www.octofrost.com
www.mpstateagro.nic.in/Global Agri System Pvt. Ltd.
https://en.wikipedia.org/wiki/Frozen_food

Ritesh. J. Mistry
M.E. Cryogenic
Zamil Air Conditioners India Pvt. Ltd., Ahmedabad

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