FOOD & DRINK TECHNOLOGY 43
rinse wheels were the standard for cooling cooked and blanched food products, but they have their drawbacks. Tese chilling methods are only as good as their ability to stop the cooking process. Pasta, rice or other food product is moved along on a conveyor or a rotary wheel while a cold water spray or chilled air is applied to the product stream to reduce its temperature after cooking. Tese systems are not capable of precisely controlling the temperature and time of the cooling process, and do not provide uniform product coverage by the water-spray or airflow. Nor do they have an adequate agitation capability to keep the product separated. Because of these factors, they are limited in their ability to uniformly halt the cooking process cycle. To thoroughly cool product from 200° to 40°F may takes as long as 20 minutes, much of this time while it is in the Bacterial Danger Zone.
A significant improvement over the shaker conveyor and rinse wheel methods is the continuous-flow cooling system which utilizes a completely enclosed rotary drum cylinder for cooling the product, directly following the cook cycle. Te drum has an internal auger to move the product through while submerged in water – a perforated skin sheet is wrapped around the drum and fixed to the auger’s flights. Tese flights gently move the product through the cooler while it is carefully agitated in the water. Consistent process parameters
for temperature, time and recipes automatically control the cooling. Te system provides increased product quality and reduced product damage to less than one percent, with several minutes reduction time in the Bacterial Danger Zone.
Te latest development in coolers for food processors represents a quantum shift in cooling speed, capable of chilling many pastas, rice, vegetables and dry beans with temperature conversion times as fast as from 200°F as the product exits the cooker to 70°F within seven seconds, to 55°F within 14 seconds, and to 40°-50°F in 21 seconds (longer times may be required for specific products). Te new chiller, developed by Lyco Manufacturing and called Easy-Flow, maintains 100 per cent uniform product cooling with less than one percent product damage for many products. But most critical is that food products pass through the Bacterial Danger Zone in seconds, greatly reducing the possibility of contamination.
Te system consists of either one, two of three cooling tanks connected in sequence. Products enter into the system through the top of the first tank, fed through a chute or conveyor from the cooker. Tey then run through the first cooling chamber, exiting through the bottom of the tank, and are then transported to the top of the tank via a pipe and onto a wedgewire- screened dewatering chute. At this point products are chilled from
Liquid dosing of powder suspensions
Handling of ingredients in powder form is often difficult especially in the baking industry. A number of products require the additions of enzymes, spices, salt in very small amounts but in a most precise concentration. Some powders are difficult to dose
in continuous systems because of their flow properties and additional care has to be taken against dust formation up to the extent of applying personal protective measures for the workers.
Oils are known to be used as dust binding agent not only in the food industry – taking this idea a bit further, one comes to the conclusion, that having a suspension of powders in oil could yield several advantages, for example, no dust formation, liquid dosing of a stock solution is more precise and easier than dosing tiny volumes of powder. Adapted to each application, Walter Rau Ag provides a wide range of oil/
fat blends with different viscosities which allow the incorporation of solids in an evenly distributed manner. These special blends do comply with the latest consumer expectations in terms of oils/ fats used and are kosher and halal and are available in different packaging.
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Walter Rau Neusser Öl und Fett AG is based in Neuss, Germany.
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200°F to 70°F in approximately 7 seconds time. Te food products can now be exported to a conveyor for downstream processing, or can immediately continue into a second in-line chamber, repeating the cycle, and converting the temperature from 70°F to 55°F, in approximately another seven seconds. Again, the food products can be exported or continue into a third in-line chill tank where they are cooled from 55° F to 40°-50° F, in approximately an additional 7 seconds. Total cycle time from 200°F to 40°F - 50°F is 21 seconds for many food products.
Each cooling stage is its own section. Additional stages (4 or 5) could be added if there is a need to cool the product even further.
Easy-Flow uses a uniquely-designed, patented plenum technology to achieve its high-speed cooling without damaging the product. Te pasta, rice, vegetables or dry beans are pulled through the cooling plenum at the bottom of each tank by Venturi effect, which increases the velocity of the fluid without pump impeller contact. Te Venturi effect creates a pressure differential that pulls the water and product through at a high speed.
Te plenum acts similar to a jet pump, with the capability of moving 300 gallons of water and product through it per minute. A jet pump, however, typically has a very high velocity jet stream running through the middle of the pipe (plenum)
“To thoroughly cool product from 200° to 40°F may takes as long as 20 minutes, much of this time while it is in the bacterial danger zone.”
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