Applications for Radio Frequency and Microwave Heating in the Food industry

The unique processing benefits achievable with RF technology have been used in food applications for many years. RF Global Solutions are working with leading food companies to develop novel food processes and products. Examples of such equipment include:

Defrosting

The process advantages include:-

  • greater yield as a result of reduced drip loss
  • shorter process time (one hour compared with 48 hours or more)
  • higher quality
  • lower bacteriological contamination

Softening

There are number of food ingredients and products which can benefit from softening either as a part of the main process or for recovery of trim or other in-process waste. The ingredients include a range of fats such as shortening for pastry making, cocoa butter and its substitutes.

Baking and post baking

Using RF “post baking’’ product throughput can be increased by up to 30%. RF assisted baking processes which can operate within ovens operating up to 300oC. The advantages of this combination baking, include:-

  • Reduced baking time.
  • More compact machines.
  • A wider choice of product characteristics arising the separate control of the surface and core heating rates.
  • Choice of full baking or part baking for finishing at point of use.
  • Novel product shapes and textures.
  • Cooking and blanching.

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Radio frequency and microwave heating techniques are useful for a range of continuous cooking operations. Their volumetric heating results in improved product quality. The range of materials which can be cooked include meats and reformed meats, pies and pizzas, vegetables and potato products.

Pasteurisation

RF and microwave techniques offers significant opportunities in extending the period between production runs of particular dishes without compromising the shelf life as seen by the customer.

RF Global Solutions also supply conventional steam heated pasteurizers.

Both microwave (MW) and radio frequency (RF) heating (also referred to as dielectric heating) refer to the application of electromagnetic waves to generate heat at regulated frequencies. The frequencies regulated by the U.S. Federal Communications Commission (FCC) for industrial, medical, and scientific purposes are 13.56, 27.12, and 40.68 MHz for RF, and, 915, 2450, 5800, and 24125 MHz for MW applications. Aside from the frequency range and penetration depth, RF and MW heating differ in the nature of the generators and applicators used. Although RF heating is more appropriate for materials of regular shape, large dimensions, and high loss factor, MW heating is better adapted for compact materials with complex shapes and low loss factor.1 Particularly, RF heating provides uniform heating because of its ability to penetrate into the product with uniform field patterns, rather than the complex nonuniform wave patterns found in the MW oven.

Continued public concerns about food hygiene issues and demand for conveniently packaged foods with enhanced nutritional quality can require rapid heating alternatives with high penetration into the product. This paper reviews published information on: 1) fundamental principles of RF heating in general; 2) relevant applications and key successes in the food industry; and 3) potential food-related applications that need further investigation.

We invite you to contact us directly for more information on RF in food processing.