Drying in foods

Loncin, M. (1988). Activity of water and its importance in preconcentration and drying of food. In Preconcentration and Drying in Food Materials (S. Bruin, ed.), p. 15. Elsevier. Amsterdam. 

FIGURE 4.4 Hot air dispersers for spray drying in food products (a) rotating distributor, (b) plug flow distributor and (c) central pipe distributor. 

Sandu, C., 1986. Infrared radiative drying in food engineering A process analysis. Biotechnology Progress, 2(3), 109-119. 

In order to avoid the aggregation of isolated RSF, the frozen RSF aqua compound was freeze-dry in Food Science, the University of Termessee, Knoxville, TN, USA. The conditions of freeze drier (Virtis Genesis 12 EL) were -20 °C to + 20 °C over 4 days in 5 °C increments. 

A 0.5113-g sample of dry dog food was ashed to remove organic materials, and the residue dissolved in a small amount of HCl and diluted to volume in a 50-mL volumetric flask. Analysis of the resulting solution gave a fluorescent emission intensity of 5.72. Determine the parts per million of Fe in the sample of dog food. 

The protein fraction is filtered and dried to become high (60%) protein content com gluten meal. The starch slurry can be dewatered and dried to produce regular com starch. Dry starch can be sold as is or heat treated in the presence of acid catalysts to produce dextrins. Or, it is chemically modified before dewatering and drying to produce modified starches used in food and industrial appHcations. Lasdy, it can be hydroly2ed to produce corn sweeteners. 

Sodium Bicarbonate. Many soda ash plants convert a portion of their production to sodium bicarbonate [144-55-8], NaHCO. Soda ash is typically dissolved, carbonated, and cooled to crystallize sodium bicarbonate. The mother Hquor is heated and recycled. The soHd bicarbonate is dried in flash or tray driers, screened, and separated into various particle size ranges. Bicarbonate markets include food, pharmaceuticals, catde feed, and fire extinguishers. U.S. demand was approximately 320,000 t in 1989 world demand was estimated at one million metric tons. 

The first pet food, a baked mixture of meat, vegetables, and wheat flour, was produced in the late 1800s. Early canned dog foods were composed mostly of meat from horses or dead stock. In the 1950s, high quaUty, nutritionally balanced, oven-baked, and pelleted dog foods became popular with dog owners and provided the most economical and satisfactory sources of dog nutrition. The extmsion process for pet foods was developed in 1954 and by 1957 extmded dog food had become the nation s leading dry pet food. 

Pet foods are produced in canned, semimoist, and dry forms. Canned pet foods contain approximately 78 to 82% water and have a strong appeal to both pets and owners. Semimoist foods have moisture contents of 25 to 50%. Dry-type foods contain 10 to 12% moisture and supply about 90% of the nutrition consumed by dogs and 72% of the nutrition eaten by cats. 

Lithium Hypochlorite. Lithium hypochlorite [13840-33-0], LiOCl, is obtained from reaction of chlorine and an aqueous solution of lithium hydroxide. The soHd is usually obtained as a dry stable product containing other alkaH haHdes and sulfates (64). A product containing 35% available chlorine is used for sanitizing appHcations in swimming pools and in food preparation areas where its rapid and complete dissolution is important. The salt can also be obtained in higher purity by reaction of lithium hydroxide and hypochlorous acid (65). 

Supercritical Fluid Extraction. Supercritical fluid (SCF) extraction is a process in which elevated pressure and temperature conditions are used to make a substance exceed a critical point. Once above this critical point, the gas (CO2 is commonly used) exhibits unique solvating properties. The advantages of SCF extraction in foods are that there is no solvent residue in the extracted products, the process can be performed at low temperature, oxygen is excluded, and there is minimal protein degradation (49). One area in which SCF extraction of Hpids from meats maybe appHed is in the production of low fat dried meat ingredients for further processed items. Its apphcation in fresh meat is less successful because the fresh meat contains relatively high levels of moisture (50). 

Potassium bicarbonate is used in foods and medicine. It is approximately twice as effective as NaHC03 in dry-powder fire extinguishers, perhaps because the potassium affects the free-radical mechanism of flame propagation. However, the material does not have good handling characteristics. 

Work in the area of simultaneous heat and mass transfer has centered on the solution of equations such as 1—18 for cases where the stmcture and properties of a soHd phase must also be considered, as in drying (qv) or adsorption (qv), or where a chemical reaction takes place. Drying simulation (45—47) and drying of foods (48,49) have been particularly active subjects. In the adsorption area the separation of multicomponent fluid mixtures is influenced by comparative rates of diffusion and by interface temperatures (50,51). In the area of reactor studies there has been much interest in monolithic and honeycomb catalytic reactions (52,53) (see Exhaust control, industrial). Eor these kinds of appHcations psychrometric charts for systems other than air—water would be useful. The constmction of such has been considered (54). 

Uses. High fmctose symp is used as a partial or complete replacement for sucrose or invert sugar in food appHcations to provide sweetness, flavor enhancement, fermentables, or humectant properties. It is used in beverages, baking, confections, processed foods, dairy products, and other apphcations. Worldwide HES production in the 1994—1995 fiscal year was estimated at about 8.6 x 10 t (dry basis) (18). About 75% of total world production is in the United States. 

Most of the thiamine sold worldwide is used for dietary supplements. Primary market areas include the following appHcations addition to feed formulations, eg, poultry, pigs, catde, and fish (see Feeds and feed additives) fortification of refined foods, eg, flours, rice, and cereal products and incorporation into multivitamins. Small amounts are used in medicine to treat deficiency diseases and other conditions, in agriculture as an additive to ferti1i2ers (qv), and in foods as flavorings. Generally for dry formulations, the less soluble, nonhygroscopic nitrate is preferred. Only the hydrochloride can be used for intravenous purposes. Coated thiamine is used where flavor is a factor. 

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