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Freeze-drying is acknowledged
worldwide, as the premium drying process for foods, supplements and anything
else containing heat sensitive material: it is the most gentle, the most
thorough and consequently, the most expensive and is Ace Nutrition's preferred
method for its products. It is typically five to seven times more expensive
than spray or air drying. Freeze-drying uses vacuum to remove the moisture:
every other industrial method uses heat which can damage the nutrients. For
example, our Upper Klamath Algae and our Botanicals are freeze-dried to
maintain maximum nutritional quality. Insist on the best - insist on
freeze-dried product: if it isn't on the label, it probable isn't freeze-dried!
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| DANIEL F. FARKAS, ASSOC. 3131 N. W. Norwood Place Corvallis, OR 97330 October 3, 1996 |
| Dear Madelaine Thank you for the opportunity to review the comments of Dr. William T. Barry, dated 9 November 1994, comparing the merits of flash air dried algae vs. freeze dried algae. My comments are based on work in the food processing industry since graduating from the Mass. Inst. of Tech. (MIT) in 1954. I have carried out research on food dehydration, have published results in refereed journals, and hold patents on a novel flash air dehydration system called the centrifugal fluidized bed drier. Examples of publications and patents are cited below. Freeze drying is the usual method of choice for drying heat sensitive biological systems. For example stock microbial cultures are routinely frozen and freeze dried for long term storage at room temperature. Starter cultures for sour dough breads are distributed in this manner. Enzymes used in food processing may be freeze dried in a similar manner with virtually all of their activity retained on rehydration. Proteins are polymers of amino acids and since freeze drying consists of two steps which do not affect the nutritional value of the protein the individual amino acids are not at all changed. The two steps necessary to freeze dry proteins, cells, or any other product are first, freezing to O° F or lower to produce a solid product mass, and second, subjecting the frozen material to a high vacuum such that the ice in the frozen mass evaporates without forming a liquid phase. This process is called sublimation and results in the product retaining its cell structure intact. Freeze dried flowers are a good example of how well cell structure can be retained by freeze drying. Freeze dried flowers have all of their natural appearance, pigments, and delicate fine structures. An active industry has been developed to deliver these flowers for permanent arrangements. Similarly taxidermists use freeze drying to preserve whole animals in lifelike form. The above examples show the unique value of the freeze drying process. By contrast, air drying takes place at temperatures above freezing. Water in the product to be dried must be heated sufficiently to allow it to evaporate through the food structure surrounding it. Flash drying, that is very rapid water evaporation, requires either a very high water temperature or a very small food particle with a lower but still substantial temperature. Small particle size, as in spray drying, means less resistance of the food structure to the evaporation of the water. Flowers and animals obviously cannot be flash dried and still retain details of their cell structure. Because drying above the freezing point of water requires careful temperature control, products flash dried on a commercial basis may be subject to temperatures and other drying conditions which could denature proteins. Other examples contrasting the quality of freeze dried versus air dried products can be found in instant dry soup garnish and instant meals for campers. Freeze dried meats and vegetables rehydrate quickly in cold or warm water while air dried meats and vegetables require soaking and cooking. You are to be commended for selecting the best available drying method for preserving the nutritional quality and integrity of their product. Sincerely,  Daniel F. Farkas Ph. D., P.E. Selected Patents and Publications on Food Drying by Daniel F. Farkas. Farkas, D. F. and M. E. Lazar. Method and apparatus for drying food. U. S. Patent No. 3,586,510. Brown, G. E. and D. F. Farkas. System for treating material with gaseous media. U. S. Patent No. 4,035,925. Carlson, R. A. , R. L. Roberts, and D. F. Farkas. Preparation of quick-cooking rice products. U. S. Patent No. 4,133,898. Lazar, M. E. and D. F. Farkas. The Centrifugal Fluidized Bed. 2. Drying Studies on Piece-form Foods. Journal of Food Science 36 (2) 315-319, 1971. Hanni, P. F., D. F. Farkas and G. E. Brown. Design and operating parameters for a continuous centrifugal fluidized bed drier. Journal of Food Science 41 (5) 1172-1179, 1976. Farkas, D. F. What are the benefits of food dehydration? The Professional Nutritionist. 14 (4) 11, 1982. |
| Last updated - 7th June 2001 |
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