Cooking vacuum drying

Harris JM (1993) Wood quahty forest management and utilization. In Walker JCF, Primary wood processing principles and practice (1st edit). Chapman and Hall, London, 560-83 Harris PJ (2005) Non-cellulosic polysaccharides in plant cell walls. In Entwistle KM and Walker JCF (eds). The HemiceUuloses Workshop 2005, Wood Technology Research Centre, University of Canterbury, Christchurch, New Zealand, 13-35 Harris RA and Taras MA (1984) Comparison of moisture content distrihution, stress distrihution, and shrinkage of red oak lumber dried by a radio-frequency/vacuum drying process and a conventional kUn. Forest Products Journal, 34 ) 44-54 Hartler N and Stade Y (1962) [Penetration and diffusion in sulphate cooking (in Swedish)]. 

Horizontal-Tank Type This type (Fig. ll-56a) is used to transfer heat for melting or cooking diy powdered solids, rendering lard from meat-scrap solids, and drying divided solids. Heat-transfer coefficients are 17 to 85 W/(m °C) [3 to 15 Btu/(h fF °F)] for drying and 28 to 140 W/(m °C) [5 to 25 Btu/(h fF °F)] for vacuum and/or solvent recovery. 

Animal fats are subjected to deodorization when a very bland or essentially flavorless fat is desired, such as in margarines or cooking fats. The fats are heated at 200°C to 260°C in the absence of air (to prevent oxidation) and treated with dry steam under a vacuum of 5-10 milliatmospheres. Off-flavor compounds are volatile under these conditions and are captured and removed in the steam stream. In addition to flavor components, free fatty acids, which can also contribute undesirable flavors, and other minor constituents such as peroxides, sterols, sterol esters, toco-pherols, and other natural antioxidants are partially or completely removed from the fat by this treatment. 

Potatoes are first cooked, and the pulp is spread by rollers over the surface of large steam heated drying drums. Bituminous coal and all kinds of granular material are handled in tubular dryers. Soap is dried when in pieces in chamber dryers, and soap flakes are handled on ribbon dryers at low temperature. Starch, casein and similar products are handled in tunnel dryers and also in rotary vacuum apparatus. Food products, fruits and vegetables are usually dried by hot air in chamber dryers. Vegetables have also been handled under vacuum, which has given an excellent product. 

Fresh whole milk is drawn into a vacuum pan and. a por its water removed. This condensation is halted while the x still in a fluid condition and before any of the milk albumen hs cooked on to the walls of the vacuum chamber. The milk i drawn from the vacuum pan and sprayed into a current, of fa The moisture in the milk is instantly absorbed by the air a particles of milk solids fall like snow. Upon examination, tb found to contain less than 2 per oent, and sometimes not mor one-half of one per cent of moisture. The hotter the air the mori the drying effect and the less, danger there is of injuring tin solids by heat. ... 

The drum dryer is also extensively used to dry and gelatinize or cook starch slurries, such as potato, rice, - wheat, " maize, com," soybean-banana, and cowpea slurries to produce pregelatinized starch for instant foods. Nonstarch, low-sugar foods, such as tomato puree, milk, skim milk, whey, beef broth, yeast," coffee, and malt extract, have also been successfully dried on a drum dryer. Heat-sensitive products such as pharmaceuticals and vitamin-containing products can be dried in a vacuum drum dryer. 

Osmotic dehydration does not allow a product of low moisture content to be considered shelf stable. Consequently, an osmotically treated product is further processed by air, vacuum, or freeze-drying methods. Osmotic pre-concentration followed by fluidized bed drying of potato pieces to produce dehydrated quick-cooking potato was studied by Ravindra and Chattopadhay [12]. They found that a solution of 50%... 

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