Future Technologies And Challenges

The world energy consumption, conservation, environmental concerns, worldwide market globalization, frozen, refrigerated, shelf stable processed food products competition and the high manufacturing costs will force the frozen food products industry to increase R&D challenges and to develop new technologies. These new technologies could be based on:

1. Equipment Automation. Improvement in equipment automation, by using sensors and computer control systems to increase equipment efficiency and maintain product consistency, quality and providing, at the same time, low freezing processing costs.

2. Equipment Flexibility. Improvement in equipment flexibility, efficiency and energy consumption. The designing of small self-contained refrigeration units which could be used in food freezing or food products distribution and storage.

3. Better Understanding of Frozen Product and Freezing Processes. Better understanding of freezing processes, food components physico-chemical properties, mathematical modeling, freezing equipment, and cooling heat transfer medium and its effects on food products, (21), will enlighten the path in improving finished frozen product quality, freezing processes and freezing equipment design.

4. Refrigerated Shipping Containers for the Frozen Food Industry. One current technological advance is the use of liquid CO2 as an alternative to CFC's in shipping containers for the frozen food industry. The liquid CO2 is transformed into a solid and it is used as the refrigerant in a system that has no mechanical moving parts. The system reduces the overall shipping costs, is cost competitive to build, efficient, and very economical (22). The system consists of pumping the liquid C02 into a tank located on top of the container where the liquid CO2 is released to atmospheric pressure turning into dry ice snow. The dry ice snow is sublimated and because of its low gas density compared with the high warm air, the tendency is to flow downward thereby maintaining the freezing temperature inside the container.

5. Manipulation of the Freezing Point. The manipulation of the freezing point of food ingredients and raw materials, by using biotechnology principles, ingredients and/or changes in its physical characteristics and chemical structure without affecting its nutritional, quality and flavor values, open new R&D opportunities. Major improvements could be accounted, (in the finished product quality, food product shelf-fife, the savings in energy conservation, and the frozen products price), if the food industry could produce, store, and distribute refrigerated and frozen raw materials, vegetables and processed food products at higher temperatures.

Other freezing opportunities are related to the freezing point depression of the finished product. The food quality improvement, ice crystallization reduction, better texture and flavor would be a few of the results of the depression of the freezing point. Using recombinant DNA techniques, or chemical methods the suppression of ice crystal growth is a reality. Application opportunities of antifreeze protein and polypeptides technology could be used in vegetables, frozen dessert, and frozen dough (23).

6. Other Liquid Nitrogen Freezing Opportunities. Utilization of liquid nitrogen, boiling point -320-F, (-196 9C), to develop small self contained units for home, distribution and food manufacturing industry use. This unit could be manufactured using compression, expansion, heat exchangers, convection heat transfer methods, and other mechanical and thermodynamic principles to freeze food products, or, use similar refrigeration cycle procedures that are currendy used.

7. Improvement in New Freezing Techniques and Processes.

- The freezing of food products involving the application of sound waves (24).

- Food products freezing using a cryogenic cooler with an inclined rotating drum (25).

- The freezing of food products by improving thermal energy storage systems to keep up with increasing capacity or as a backup refrigeration.

8. Low Temperature Thermal Energy Storage System (SECO2). This revolutionary system is a low temperature thermal storage system that uses the latent heat of carbon dioxide, 84 Btu/lb, at its triple point (26).

The system is described as follows: "This thermodynamic state for the CO2 exists at -70^ and 60 psig. In the SECO2, Stored Energy in CO2, the solid is formed with a conventional cascade chiller and it is accumulated in a storage vessel which initially contains all liquid.

The chiller operates at full load and draws CO2 vapor directly from the vessel vapor space as the low stage refrigerant. Cooling is supplied from the vessel by circulating CO2 liquid from the vessel through a process heat exchanger. The vaporized CO2 returns to the vessel and condenses directly against the solid/liquid slush" (26). This versatile and flexible thermal storage refrigeration system could benefit the Chemical, Petrochemical, Food Freezing Pharmaceutical, Gas liquefaction processes and Industries.

9. Freeze Flo Technology. It consists of producing food products that remain soft, firm in texture, high in stability, and ice free, maintaining its integrity, shape and consistency. Free water activity which encourage microbiological concerns is eliminated by the freeze flow process (27). This technology is currently used in developing freeze flow fruits with application in ice cream, desserts, and other frozen food product dishes. This technology could also be used in developing enrobed frozen food products, cakes, pies, pastries, and other added value food products.

10. Microwave use in Freeze Drying Process. This technology consists of using the microwave heating technology in subliming the freezing water as the food product is freeze-dried. Improvements in finished product quality, drying processing times, and organoleptic characteristics are obtained. The U.S. Army Natick RD&E Center, Mass., tests on peas and beans showed reduction in drying processing time that is proportional to the microwave wattage levels (28).

The effectiveness of the process is based on the sublimation of the ice caused by the microwave absorption and conduction and convection heat transfer (28). This new technology could be expanded to other vegetables or food products that require freeze-drying procedures.

11. Freezing Extrusion. The application of extrusion principles and freeze flow technology in generating frozen food products and equipment flexibility to be used in the Frozen Manufacturing Industry.

12. Liquid Concentration by Freezing. This technology is based on the separation of the ice crystal formed from the concentrated liquid during the freezing concentration process. Challenge and success of this technology reside in the optimization of the process and equipment scale-up. This improved technology could be widely applied in concentrating liquids without using thermal evaporators. Better organoleptic attributes, finished product quality, lower handling and transportation costs could be obtained with the application and mastering of this technology (29).

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