Diese Präsentation wurde erfolgreich gemeldet.
Die SlideShare-Präsentation wird heruntergeladen. ×

Ohmic heating

Weitere Verwandte Inhalte

Ähnliche Bücher

Kostenlos mit einer 30-tägigen Testversion von Scribd

Alle anzeigen

Ähnliche Hörbücher

Kostenlos mit einer 30-tägigen Testversion von Scribd

Alle anzeigen

Ohmic heating

  1. 1. What is ohmic heating Ohmic heating is an advanced thermal processing method wherein the food material, which serves as an electrical resistor, is heated by passing electricity through it. Electrical energy is dissipated into heat, which results in rapid and uniform heating. Ohmic heating is also called electrical resistance heating, Joule heating, or electro-heating, and may be used for a variety of applications in the food industry
  2. 2. How is ohmic heating different from conventional thermal processing During conventional thermal processing, either in cans or aseptic processing systems for particulate foods, significant product quality damage may occur due to slow conduction and convection heat transfer. ohmic heating volumetrically heats the entire mass of the food material, thus the resulting product is of far greater quality than its canned counterpart.
  3. 3. How is ohmic heating different from conventional thermal processing It is possible to process large particulate foods (up to 1 inch) that would be difficult to process using conventional heat exchangers. ohmic heater cleaning requirements are comparatively less than those of traditional heat exchangers due to reduced product fouling on the food contact surface.
  4. 4. Products suitable for ohmic heating Ohmic heating can be used for heating liquid foods containing large particulates, such as soups, stews, and fruit slices in syrups and sauces, and heat sensitive liquids The technology is useful for the treatment of proteinaceous foods, which tend to denature and coagulate when thermally processed. liquid egg can be ohmically heated in a fraction of a second without coagulating it.
  5. 5. Products suitable for ohmic heating Juices can be treated to inactivate enzymes without affecting the flavor. Other potential applications of ohmic heating include blanching, thawing, on-line detection of starch gelatinization, fermentation, peeling, dehydration, and extraction.
  6. 6. Microorganisms inactivation by ohmic heating Like thermal processing, ohmic heating inactivates microorganisms by heat Also non-thermal electroporation type effects have been reported at low-frequency (50�60 Hz), when electrical charges can build up and form pores across microbial cells, however, it is not necessary to claim such effects since heating is the main mechanism. Electroporation is a significant increase in the electrical conductivity and permeability of the cell plasma membrane caused by an externally applied electrical field
  7. 7. shelf life of an ohmically processed product The shelf life of ohmically processed foods is comparable to that of canned and sterile, aseptically processed products
  8. 8. ohmically processed commercial products available on the market A number of processing plants currently produce sliced, diced, and whole fruit within sauces in various countries, including Italy, Greece, France, Mexico, and Japan. In the United States, ohmic heating has been used to produce a low-acid particulate product in a can, as well as pasteurized liquid egg.
  9. 9. ohmic heating environmentally friendly This process uses ordinary electricity. No emissions are produced at the point of use. One emerging application of ohmic heating is fruit peeling, which may greatly reduce the use of lye that is common to such operations, and results in environmental benefits. Lye is a corrosive alkaline substance, commonly sodium hydroxide Lye is valued for its use in food preparation, soap making, and household uses, such as oven cleaner and drain opener.

×