X-Message-Number: 25152 Date: Wed, 24 Nov 2004 14:29:41 -0800 (PST) From: Jeff Davis <> Subject: Re: Magnetic resonance freezing "leo" offered: Message #25145 From: "leo" <> Subject: Magnetic resonance freezing Date: Wed, 24 Nov 2004 00:26:15 +0100 maybe somting interesting on page 24 of this pdf http://www.flair-flow.com/industry-docs/sme-syn10.pdf you can by the original article overhere http://www.airah.org.au/tec_dow_an_art.asp#archive the article is out of 2001. ********************************* I thought it a valuable submission, so I copied out the page 24 section, and offer it here for all to see. Note that Figure 16 is a graphic and I was not able to copy and reproduce it here. Best, Jeff Davis "Everything's hard till you know how to do it." Ray Charles ********************************* III.3 Magnetic resonance freezing As already discussed, the conventional refrigeration equipment provides freezing rates which, as a rule, are insufficient to eliminate completely undesirable water migration and mass transfer within a food product undergoing freezing. Realising this circumstance, researchers decided that if water could somewhat be retained within the cells while freezing, then the cells would not become dehydrated and foodstuff could keep its original attributes and freshness. A system for Magnetic Resonance Freezing (MRF) preventing such cellular dehydration could be regarded as composed of a common freezer and a special magnetic resonance device. The MRF process (Figure 16) is then effected at the following two steps [Ref. 7]: Step 1: Food undergoes continuos magnetic wave vibrations, which provide for: Impeding the crystallisation; Supercooling below the initial freezing point. Step 2: After a suitable product-specific period of time the magnetic fields are abruptly removed with many resulting quality benefits for the end frozen product, e.g.: Uniform flash freezing of the entire food volume; Quick passing through the critical temperature zone of intense water crystallisation (between 1 and 6 oC); Fine ice structure in foods; No water migration and undesirable mass transfer phenomena; No cellular dehydration; Avoiding cracks and related damages; Protected integrity of food tissues. MRF data are still kept as a confidential know-how of a number of companies. Although strongly boasted [Ref. 7], MRF equipment should also prove its claimed advantages and capabilities through extensive tests within a sufficiently representative industrial environment. Further information on other interesting technology innovations concerning food freezing (e.g. novel cryogenic modes, unique dehydrofreezing techniques, freeze drying, partial freezing, vacuum and heat pipe applications) could be found in Refs 8-10. ****** Here are those "Refs"***** 6. Schl ter O., George S., Heinz V. and Knorr D. (2000) Phase transitions in model foods, induced by pressure-assisted freezing and pressure-assisted thawing. In Advances in the Refrigeration Systems, Food Technologies and Cold Chain, ed.: K. Fikiin, IIR Proceedings Series Refrigeration Science and Technology , 1998/6, pp. 240-248. 7. Mohanty P. (2001) Magnetic resonance freezing system. AIRAH Journal, Vol. 55, No. 6, pp. 28-29. 8. Sun Da-Wen, Ed. (2001) Advances in Food Refrigeration. Leatherhead Publishing, Surrey, 482 p. 9. Magnussen O.M., Nordtvedt T.S. and Torstveit A.K. (2000) Use of partial freezing in the cold chain. In Advances in the Refrigeration Systems, Food Technologies and Cold Chain, ed.: K. Fikiin, IIR Proceedings Series Refrigeration Science and Technology , 1998/6, pp. 363-370. 10. James C., Ketteringham L. and James S.J. (2000) Enhanced heat transfer in food chilling, freezing and thawing using heat pipes. In Advances in the Refrigeration Systems, Food Technologies and Cold Chain, ed.: K. Fikiin, IIR Proceedings Series Refrigeration Science and Technology , 1998/6, pp. 327-333. __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=25152