Edible

Modern methods of amino-acid and peptide analysis, have enabled the complete amino-acid sequence of a number of proteins to be worked out. The grosser structure can be determined by X-ray diffraction procedures. Proteins have molecular weights ranging from about 6 000 000 to 5 000 (although the dividing line between a protein and a peptide is ill defined). Edible proteins can be produced from petroleum and nutrients under fermentation. 

Starch can be split into amylose and amylopectin by a commercial process based on selective solubilities. Amylose is used for making edible films, and amylopectin for textile sizing and finishing, and as a thickener in foods. 

Fats can be an important source of lubrication in the preparation and consumption of foods (30). Marble slabs on which hot candy is poured are lubricated with fat to prevent sticking. Also, bread and cake pans are treated with heatstable edible oil. 

W. H. Meyer, Food Fats and Oils, Institute of Shortening and Edible Oils, Washington, D.C., 1982, 22 pp. 

In milk fat, cholesterol is associated with Hpoproteins in the milk fat globule. It is also a component of animal membranes and controls rigidity and permeabihty of the membranes. Cholesterol has interesting surface properties and can occur in Hquid crystalline forms. Plants contain sterols such as P-sitosterol [83-46-5] (4b) or stigmasterol [83-48-7] (4c). Their functions in plant metaboHsm are not yet well understood. Analysis of sterols has proven useful for detection of adulteration of edible fats (9). 

Cmde oils from these processes are often of insufficient quaUty to be used directly, particularly for edible products. Impurities such as pigments, phosphatides, volatile odorous compounds, and certain metals must be removed by further processing. 

Chemical bleaching is never used on oils intended for edible use because it oxidizes unsaturated fatty acids to cause off-flavors. However, it does find wide usage for specialty linseed oil, for the paint industry, and fatty chemicals such as sorbitan esters of fatty acids and sodium stearoyl lactylate. Residual peroxide is destroyed by heating above its decomposition temperature. 

Smoke, Flash, and Fire Points. These thermal properties may be determined under standard test conditions (57). The smoke poiat is defined as the temperature at which smoke begias to evolve continuously from the sample. Flash poiat is the temperature at which a flash is observed whea a test flame is appHed. The fire poiat is defiaed as the temperature at which the fire coatiaues to bum. These values are profouadly affected by minor coastitueats ia the oil, such as fatty acids, moao- and diglycerides, and residual solvents. These factors are of commercial importance where fats or oils are used at high temperatures such as ia lubricants or edible frying fats. 

Technical data, "Typical Composition and Chemical Constants of Common Edible Eats and Oils", Durkee Industrial Eoods, 1992. 

Cake discharge occurs at atmospheric pressure by the action of a toU or a scraper, assisted by blowback. The cloth may be washed by a spray before the cycle starts again. Filtering areas range up to 8 m and dmm diameters up to 2 meters. The necessity for large seals limits the operating pressure to less than 300 kPa, typically. Cake thickness can be from 2 to 150 mm, depending on machine size, and the speed of dmm rotation up to 2 rpm, usually from 0.3 to 1 rpm. Apphcations occur in the manufacture of pharmaceuticals, dyestuffs, edible oils, and various chemicals and minerals. 

A. M. Pearson andT. R. Dutson, eds.. Edible Meat by-Products Advances in Meat Research, Vol. 5, Elsevier Science PubHshing Co., Inc., New York, 1989. 

Withdrawal from anaboHc steroid treatment is not required before slaughter because residue levels in edible tissues are negligible, and are significantly lower than other sources of estradiol such as the normal endogenous production in humans and the phytoestrogens consumed in plant food sources (1). 

The abihty of algiaates to form edible gels by reaction with calcium salts is an important property. Calcium sources are usually calcium carbonate, sulfate, chloride, phosphate, or tartrate (20). The rate of gel formation as well as the quaUty and texture of the resultant gel can be controlled by the solubihty and availabiUty of the calcium source. 

J. A. Duke, Edible Weeds, CRC Press, Boca Raton, Fla, 1992. 

Rotenoids. The use of rotenone-bearing roots as insecticides in the United States was developed as a result of federal laws against residues of lead, arsenic, and fluorine upon edible produce. Rotenone [83-79-4] (5) is harmless to plants, highly toxic to many insects, and relatively innocuous to... 

Rotenone-containing iasecticides have been used as dusts of ground roots, dispersible powders, and emulsive extracts. Their principal uses have been for appHcation to edible produce just prior to harvest and for the control of animal ectoparasites and cattle gmbs. 

---